Breslow Depth (Melanoma)

Breslow Depth Analyzer

Melanoma Management Matrix

Pathology Parameters

Breslow Thickness0 mm

In Situ5.0 mm10.0 mm

Depth Logic

Adjust the Breslow thickness and ulceration status to resolve surgical recommendations.

Guidelines & Evidence

Verified

Last Review: 2026-07-17

When to Use

What is Breslow Depth?

Breslow depth (also called Breslow thickness) is the single most important prognostic factor for primary cutaneous melanoma. It measures the vertical thickness of the tumor from the top of the granular layer of the epidermis (or from the base of the ulcer if the tumor is ulcerated) to the deepest point of tumor invasion in the dermis or subcutaneous fat. The measurement is expressed in millimeters (mm) to two decimal places and is used to determine the T category (tumor stage) in the AJCC (American Joint Committee on Cancer) staging system. Breslow depth directly correlates with the risk of lymph node metastasis, distant metastasis, and overall survival.

Primary Clinical Applications

Melanoma staging (AJCC 8th Edition) – Breslow depth determines T category (Tis, T1a, T1b, T2a, T2b, T3a, T3b, T4a, T4b), which combines with nodal status (N) and metastatic status (M) for overall stage grouping (0-IV)

Sentinel lymph node biopsy (SLNB) decision-making – Breslow depth ≥0.8 mm (or ≥0.8 mm with ulceration, mitotic rate ≥1/mm², or other high-risk features) is an indication for discussion of SLNB

Surgical margin determination – Breslow depth determines the required wide local excision (WLE) margin (0.5 cm for in situ, 1.0 cm for ≤1.0 mm, 1.0-2.0 cm for 1.01-2.0 mm, 2.0 cm for >2.0 mm)

Prognostic counseling – Provides quantitative estimate of recurrence and survival risk (e.g., T1a ≤0.8 mm, no ulceration: 5-year survival 99%; T4b >4.0 mm with ulceration: 5-year survival ~50-60%)

Adjuvant therapy decisions – For resected stage III melanoma (positive SLNB), Breslow depth of primary is one factor in recurrence risk assessment (along with number of positive nodes, ulceration, and nodal burden)

Clinical trial eligibility – Many adjuvant therapy trials (immunotherapy, targeted therapy) use Breslow depth and SLNB status as inclusion criteria

Research and quality measurement – Standardized reporting across institutions enables meta-analyses, guideline development, and benchmarking

Anatomical Principles: How Breslow Depth is Measured

Key measurement rules (AJCC 8th Edition, CAP protocol): • Start point: Top of the granular layer of the epidermis (the stratum granulosum, just below the stratum corneum). If the epidermis is ulcerated (loss of epithelium), measure from the base of the ulcer (the tumor-air interface), not from the presumed original granular layer. • End point: The deepest continuous or non-continuous tumor cell at the leading invasive front. Include satellite tumor nests, single cells, and tumor cells tracking along adnexal structures (hair follicles, sweat glands, sebaceous glands). Do NOT include inflammatory cells, fibrosis, or non-tumoral melanin-laden macrophages. • Measurement tool: Ocular micrometer calibrated to the objective lens (typically 0.5 mm increments for scanning power, 0.1 mm for high power). Measure perpendicular (vertical) from the start point to the deepest invasive cell using a line perpendicular to the epidermal surface. • Multiple measurements: For tumors with irregular contours, measure from the highest point of the granular layer (or ulcer base) to the deepest invasive cell. In some cases (large desmoplastic melanoma), multiple measurements may be taken; report the greatest thickness. • Microscopic satellites: Tumor nests separated from the main mass by normal tissue (not fibrosis) should be included in the measurement if they are within 0.5 mm of the main invasive front. If beyond 0.5 mm, they are counted separately as microsatellitosis (upstages to N stage, not T).

Comparison with Clark Level

Feature	Breslow Depth	Clark Level
Definition	Vertical tumor thickness in millimeters from granular layer (or ulcer base) to deepest invasive cell	Anatomic level of invasion (I-V) based on dermal layers
Levels/Categories	Continuous variable (0.1 to 20+ mm), categorized into AJCC T categories (T1-T4)	5 ordinal levels: I (intraepidermal), II (papillary dermis), III (papillary-reticular interface), IV (reticular dermis), V (subcutaneous fat)
Inter-observer reliability	High (0.85-0.95 correlation coefficient, precise measurement)	Low to moderate (kappa 0.45-0.65, subjective boundaries of dermal layers)
Prognostic power	Superior (single most important prognostic factor per AJCC)	Inferior (no longer used in AJCC 8th Edition for T staging, but may be reported for historical completeness)
Use in AJCC 8th Edition	Primary determinant of T category (T1-T4 based on thickness and ulceration)	Not used in formal staging (dropped after AJCC 5th Edition in 2001)
Correlation with SLNB positivity	Continuous: 5% (≤0.8 mm), 10-15% (0.8-1.0 mm), 15-25% (1.01-2.0 mm), 30-45% (2.01-4.0 mm), >50% (>4.0 mm)	Clark IV/ V higher risk than Clark II/III, but does not add independent prognostic information after adjusting for Breslow
Clinical utility (2024)	Essential for staging, margins, SLNB decision, and adjuvant therapy	Historical; rarely used in modern clinical decision-making except for T1a classification (≤0.8 mm AND no ulceration AND Clark level IV may upstage to T1b? Controversial; NCCN does not recommend)

AJCC 8th Edition T Categories (2018, updated with data from 13,000+ patients)

T Category	Breslow Depth (mm)	Ulceration Status	Estimated 5-year Survival (Stage I-II)	SLNB Positivity Rate	Management Implications
Tis (in situ)	N/A (no invasion; melanoma confined to epidermis)	Not applicable	~99-100%	<1% (rarely positive)	Wide local excision with 0.5-1.0 cm margins, no SLNB, no adjuvant therapy. Complete excision is curative.
T1a	≤0.8 mm	No ulceration	~99% (similar to Tis)	~5-7% (low, but not zero)	WLE with 1.0 cm margins. SLNB may be considered if mitotic rate ≥1/mm², lymphovascular invasion, or patient young age (but NCCN: discussion for T1b only). Controversial; most guidelines do NOT recommend routine SLNB for T1a.
T1b	≤1.0 mm	Yes (ulceration) OR 0.8-1.0 mm regardless of ulceration	~97-98%	~10-15% (higher if ulcerated)	WLE with 1.0 cm margins. SLNB recommended for discussion (NCCN: consider SLNB for T1b, especially if ulcerated or high mitotic rate). Adjuvant therapy not standard (unless SLNB positive).
T2a	1.01 - 2.0 mm	No ulceration	~93-96%	~15-20%	WLE with 1.0-2.0 cm margins (1 cm acceptable, 2 cm preferred by some). SLNB indicated (NCCN Category 1 recommendation). If SLNB negative, observation. If SLNB positive, complete lymph node dissection or nodal observation (MSLT-II trial), consider adjuvant immunotherapy.
T2b	1.01 - 2.0 mm	Yes (ulceration)	~90-93%	~25-30%	Same as T2a but higher risk; SLNB mandatory. Adjuvant therapy if SLNB positive. Consider baseline imaging (CXR, LDH) due to higher risk.
T3a	2.01 - 4.0 mm	No ulceration	~85-90%	~30-40%	WLE with 2.0 cm margins. SLNB indicated (Category 1). Baseline imaging (CXR, LDH, CT chest/abdomen/pelvis if high-risk symptoms or for clinical trial). Adjuvant therapy if SLNB positive.
T3b	2.01 - 4.0 mm	Yes (ulceration)	~75-85%	~40-50%	Same as T3a but higher risk. Baseline imaging recommended (CT or PET-CT) even if SLNB negative (due to higher distant metastasis risk).
T4a	>4.0 mm	No ulceration	~70-80%	~50-65%	WLE with 2.0 cm margins. SLNB indicated. Baseline imaging required (CT chest/abdomen/pelvis or PET-CT). Consider adjuvant immunotherapy even if SLNB negative? NCCN: For T4 (≥4 mm), consider adjuvant therapy discussion if high risk (ulcerated, positive SLNB, multiple primaries).
T4b	>4.0 mm	Yes (ulceration)	~50-60%	~65-75%	Same as T4a. Very high risk. SLNB mandatory. Baseline imaging required. Strongly consider adjuvant immunotherapy (anti-PD-1, e.g., pembrolizumab, nivolumab) even if SLNB negative (based on extrapolation from stage III trials and high recurrence risk). Clinical trial if available.

How it Works

Step-by-Step Measurement Guidelines (AJCC 8th / CAP Protocol)

Special Measurement Scenarios

Scenario	Measurement Rule	Example	Impact on Staging
Ulcerated melanoma	Measure from the base of the ulcer (tumor-air interface) to the deepest invasive cell	Breslow depth from granular layer would be 2.5 mm, but ulcer base is 0.3 mm lower, so measured depth = 2.8 mm	Higher T category (e.g., T2a → T2b if 1.01-2.0 mm with ulceration; T2b to T3a if crosses 2.0 mm threshold). Higher risk of SLNB positivity.
Satellite tumor nests (within 0.5 mm of main tumor)	Include satellite nests in measurement if within 0.5 mm of deepest invasive front	Main tumor depth 1.5 mm, but separate nest at 2.0 mm within 0.5 mm of main front? Include: measured depth = 2.0 mm	Higher T category (upstages from T2a to T3a if crosses 2.0 mm threshold). Microsatellites beyond 0.5 mm counted separately in N category, not T.
Tumor cells tracking along hair follicle or sweat gland	Include depth of tumor cells along adnexal structures, even if deep	Melanoma cells extend 3.5 mm down a hair follicle (continuous with superficial tumor)	Measured depth = 3.5 mm (T3 if 2.01-4.0 mm). These are not "microsatellites" (they are contiguous).
Desmoplastic melanoma	Measure from granular layer to deepest spindle cell (desmoplastic component)	Superficial epithelioid component 0.8 mm, deep desmoplastic component 4.5 mm	Measured depth = 4.5 mm (T4). Desmoplastic melanoma often underestimated on punch biopsy; need complete excision for accurate measurement.
Thin melanoma with regression	If invasive component is destroyed by regression, measure from granular layer to deepest remaining tumor. If no invasive tumor remains, report as "no measurable Breslow depth; regression only"	Original invasion depth unknown due to lymphocytic infiltrate destroying tumor	Cannot stage accurately; consider complete excision and close clinical follow-up. May be upstaged based on regression thickness? Controversial. AJCC recommends measuring residual tumor only.
Subungual melanoma (nail bed)	Measure from the base of the nail plate (if ulcerated) or from the granular layer of the nail bed epithelium	Subungual melanoma with Breslow depth 2.5 mm	Same T staging as cutaneous melanoma. No specific nail adjustments. Important to report depth for surgical margin decisions (amputation vs wide local excision).

Sentinel Lymph Node Biopsy (SLNB) Indications by Breslow Depth (NCCN v3.2023)

Breslow Depth	Ulceration	Mitotic Rate	SLNB Recommendation	Level of Evidence	Notes
<0.8 mm (T1a)	No	Any (including 0/mm²)	Not recommended (low yield, <5% positivity)	NCCN Category 3 (no benefit), but some centers discuss for mitotic rate ≥2/mm² or young age	False-negative rate low, but risk of complications (lymphedema, seroma, nerve injury). Observation recommended.
0.8 - 1.0 mm (T1b)	Any (including no ulceration)	Any	Discuss SLNB (NCCN Category 2B)	Positivity rate 10-15%. Consider if patient fit for surgery, high mitotic rate (>2/mm²), young age (<40 years), or patient desires prognostic information.
1.01 - 2.0 mm (T2a/T2b)	Either	Any	SLNB indicated (NCCN Category 1)	Positivity rate 15-30%. Standard of care. If SLNB positive, complete lymph node dissection (CLND) or nodal observation (MSLT-II trial showed no survival benefit for CLND but improved regional control).
2.01 - 4.0 mm (T3a/T3b)	Either	Any	SLNB indicated (NCCN Category 1)	Positivity rate 30-50%. Mandatory. Baseline imaging recommended. Adjuvant therapy (pembrolizumab, nivolumab, dabrafenib/trametinib if BRAF mutant) if SLNB positive.
>4.0 mm (T4a/T4b)	Either	Any	SLNB indicated (NCCN Category 1)	Positivity rate 50-75%. Mandatory. Baseline imaging required. Adjuvant therapy strongly recommended (even if SLNB negative? Controversial; some guidelines recommend for T4b regardless of nodal status due to high recurrence risk).

Surgical Margins by Breslow Depth (NCCN, AAD, ASDS Guidelines)

T Category	Breslow Depth	Recommended Margin (cm)	Evidence Base	Surgical Technique Considerations
In situ (Tis)	N/A	0.5 - 1.0 cm	5-year local recurrence rate <2% with 0.5 cm margin	Standard excision or Mohs micrographic surgery for lentigo maligna (face, scalp, other cosmetically sensitive areas)
T1a (≤0.8 mm, no ulceration)	≤0.8 mm	1.0 cm	1.0 cm margin vs 2.0 cm: no difference in local recurrence (RCT, 1 cm non-inferior)	1 cm margin recommended (less morbidity than 2 cm). Can be performed with primary closure in most anatomic sites.
T1b (≤1.0 mm with ulceration OR 0.8-1.0 mm regardless)	≤1.0 mm	1.0 cm	Same as T1a (extrapolated)	1 cm margin standard. SLNB discussion as above.
T2a/T2b (1.01-2.0 mm)	1.01-2.0 mm	1.0 - 2.0 cm	1 cm margin may be adequate per some trials (Swedish Melanoma Study Group, 1 cm vs 2 cm RCT for 0.8-2.0 mm). NCCN accepts 1 cm or 2 cm.	Many surgeons prefer 2 cm for 1.01-2.0 mm due to lower local recurrence (1-2% vs 3-4% with 1 cm), but no survival difference. 1 cm acceptable for cosmetically sensitive areas (face, scalp, hands, feet).
T3a/T3b (2.01-4.0 mm)	2.01-4.0 mm	2.0 cm	2 cm margin standard (Intergroup Melanoma Surgical Trial, 2 cm vs 4 cm: no difference in survival, lower morbidity with 2 cm)	2 cm margin. May require skin graft or flap for closure. Consult plastic surgery for complex sites.
T4a/T4b (>4.0 mm)	>4.0 mm	2.0 cm	Same as T3 (2 cm vs 4 cm trials included some >4 mm patients, no benefit to wider margins)	2 cm margin. Skin graft often required. Consider preoperative imaging to rule out distant metastasis before surgery (if not already done).

Clinical Pearls

Critical Pearl #1: T1a (≤0.8 mm, no ulceration) Has Excellent Prognosis but NOT Zero Risk

T1a melanoma (≤0.8 mm, no ulceration) has 5-year survival ~99% and SLNB positivity rate ~5-7%. However, the risk is not zero. Factors that increase risk in thin melanoma: • Mitotic rate ≥1/mm²: Increases SLNB positivity risk from ~5% to ~10-15% in T1a. Some guidelines consider SLNB for T1a with mitotic rate ≥1/mm² (controversial, not in NCCN but used in Europe/Australia). • Young age (<40 years): Higher SLNB positivity in thin melanoma (possibly due to more robust immune response or biologic differences). • Lymphovascular invasion (LVI): Rare in T1a but if present, increases metastasis risk. • Tumor-infiltrating lymphocytes (TILs): Brisk TILs in thin melanoma associated with better prognosis (protective). Absent TILs → higher risk. Clinical approach: For patients with T1a melanoma, do NOT reassure them that "risk is zero." Instead: "Your risk of the melanoma spreading to lymph nodes is low, about 5 in 100. We don't routinely recommend a sentinel lymph node biopsy because the chance of finding a positive node is small, and the procedure has side effects. We will monitor you closely with regular skin exams." If patient has high-risk features (mitotic rate ≥2/mm², age <30, LVI present), some centers offer SLNB (off-label but acceptable per shared decision-making).

Critical Pearl #2: Ulceration Automatically Upstages T Category

Ulceration (loss of epidermis overlying the melanoma) is a powerful adverse prognostic factor that upstages the T category. For example: • T1a: ≤0.8 mm, no ulceration (5-year survival ~99%) • T1b: ≤1.0 mm WITH ulceration (or 0.8-1.0 mm regardless of ulceration) (5-year survival ~97-98%) • T2a: 1.01-2.0 mm, no ulceration (5-year survival ~93-96%) • T2b: 1.01-2.0 mm WITH ulceration (5-year survival ~90-93%) Why ulceration matters: Ulceration is a marker of rapid tumor growth outpacing blood supply, leading to ischemia and necrosis. It correlates with higher mitotic rate, lymphovascular invasion, and genomic instability. Clinical implication: A patient with a 1.2 mm melanoma but ulceration (T2b) has worse prognosis than a patient with 1.8 mm melanoma without ulceration (T2a). Always check the pathology report for ulceration status. When discussing prognosis, incorporate ulceration: "Your melanoma is 1.2 mm thick, but because it is ulcerated, your risk is similar to someone with a 2 mm thick non-ulcerated melanoma."

Critical Pearl #3: Microsatellitosis Upstages N Category, NOT T Category

Microsatellitosis refers to small nests of tumor cells >0.5 mm from the main invasive front but within the dermis or subcutaneous fat. Crucial distinction: Microsatellites are NOT included in Breslow depth (only satellites within 0.5 mm of the main tumor are included). Microsatellites beyond 0.5 mm are recorded separately and upstage the N category (nodal stage) to N2c or N3c, even if the sentinel lymph node is negative. Example: Primary melanoma Breslow depth 1.5 mm (T2a), no ulceration, but pathology identifies a 0.3 mm satellite nest 1.2 mm from the main tumor. SLNB negative. Stage: T2a (Breslow 1.5 mm), N2c (microsatellites without nodal metastases), M0 → Overall stage IIIB (not IIA). Management implication: Patients with microsatellitosis (even with negative SLNB) are staged as IIIB/IIIC and are eligible for adjuvant immunotherapy (pembrolizumab, nivolumab) based on the KEYNOTE-054 and CheckMate 238 trials, which included stage III patients with microsatellites. Clinical action: If your pathology report mentions "microsatellitosis" or "satellites," calculate stage carefully. Stage III patients should be referred to medical oncology for adjuvant therapy discussion.

Critical Pearl #4: Breslow Depth on Shave vs Punch vs Excisional Biopsy

Excisional biopsy (full-thickness, with 1-2 mm margin) is preferred for suspected melanoma. However, in practice, many are diagnosed on shave or punch biopsy. • Shave biopsy (superficial): May transect the deep margin, making Breslow measurement impossible (reported as "Breslow depth cannot be accurately determined due to transection"). Up to 20-30% of shave biopsies transect the deep margin, underestimating thickness. - Action: If shave biopsy shows melanoma but depth cannot be measured, perform a completion excision (wide local excision) and submit the excision specimen for definitive Breslow measurement. - Exception: If shave biopsy shows in situ melanoma only, but deeper margin may have invasive cells (sampling error). Still require excision. • Punch biopsy (3-6 mm): May sample only part of the tumor; may miss the thickest portion (sampling error). Up to 10-15% of punch biopsies underestimate Breslow depth. - Action: For punch biopsy with invasive melanoma, complete excision is required for accurate staging. Use the punch biopsy depth as a minimum (e.g., "at least 0.8 mm" pending excision). • Excisional biopsy (preferred): Complete removal with 1-2 mm margins. Provides accurate Breslow depth, margin assessment, and diagnosis in one procedure. Clinical pearl: When you receive a shave or punch biopsy result, do NOT assume the Breslow depth is final. Complete excision may reveal deeper invasion. Conversely, shave biopsy may fragment the specimen, making measurement impossible. Always recommend complete excision for staging if biopsy technique was suboptimal.

Common Pitfalls and Errors in Breslow Interpretation

Measuring from the wrong start point (ulcerated melanoma) – Failure to measure from the ulcer base (instead measuring from the granular layer of adjacent non-ulcerated skin) underestimates Breslow depth, downstaging the tumor. Ensure pathology report states "ulcerated" and measurement is from ulcer base.

Including inflammatory cells or melanophages in measurement – Deep inflammation (lymphocytes, macrophages) may mimic tumor cells. Only measure tumor cells with malignant cytology (nuclear atypia, mitoses, pleomorphism).

Excluding deep tumor cells along adnexal structures – Melanoma cells often track down hair follicles or sweat glands. These cells are contiguous with the main tumor and MUST be included in Breslow depth. Failure to include them underestimates thickness.

Misclassifying microsatellites as part of Breslow depth – Microsatellites beyond 0.5 mm should NOT be included in Breslow depth; they upstage N category, not T. Some pathologists incorrectly add microsatellite depth to Breslow, leading to overstaging (e.g., reporting T4 when actual T2, but microsatellites present).

Assuming thicker always equals worse prognosis (ignoring ulceration) – A 2.5 mm non-ulcerated melanoma (T3a) has better prognosis than a 1.5 mm ulcerated melanoma (T2b). Compare T categories, not thickness alone.

Applying adult Breslow thresholds to pediatric melanoma – Pediatric melanomas (age <18 years) have different biology; thin melanomas (T1a/T1b) in children may have higher SLNB positivity rates than adults (up to 15-20% for T1a vs 5% in adults). Thresholds for SLNB may be lower. Consult pediatric oncology guidelines.

Ignoring mitotic rate in T1b decision-making – For T1b (≤1.0 mm with ulceration or 0.8-1.0 mm regardless), mitotic rate ≥2/mm² may increase risk of SLNB positivity further. Use clinical judgment, not just Breslow.

Failing to adjust management for desmoplastic melanoma – Desmoplastic melanoma often has deeper Breslow depth (requires wide excision) but lower SLNB positivity (20-30% less than non-desmoplastic). Some guidelines recommend SLNB still, but recurrence patterns differ (more local recurrence, less nodal).

Integrated Risk Calculator (Melanoma Recurrence, SLNB Positivity)

Online tools (e.g., Melanoma Risk Calculator from MIA (Melanoma Institute Australia), MSKCC Nomogram) combine Breslow depth, ulceration, age, site, and mitotic rate to estimate SLNB positivity risk and melanoma-specific survival. For a 50-year-old patient with 0.9 mm (T1b) melanoma on the trunk, no ulceration, mitotic rate 1/mm²: • SLNB positivity risk predicted: 11% (95% CI: 8-15%) • 5-year melanoma-specific survival (SLNB negative): 98% • 5-year melanoma-specific survival (SLNB positive): 85% Use these tools for shared decision-making, especially for T1b melanomas where SLNB is optional. Always document the discussion.

Next Steps

Step-by-Step Clinical Action by Breslow Depth

Surveillance Schedule by Stage (NCCN v3.2023)

Stage (Based on Breslow and SLNB)	History and Skin Exam Frequency	Imaging Recommendations	Duration of Follow-up
Stage IA (T1a, N0)	Every 6-12 months for 1-2 years, then annually	None routinely (CXR, LDH only if symptoms or high risk)	At least 3-5 years; consider longer for patients <40 years
Stage IB-IIA (T1b-T2a, N0)	Every 6-12 months	None routinely; consider baseline CXR and LDH (optional)	5 years minimum; some guidelines recommend 10 years for high-risk (T2a, young age)
Stage IIB-IIC (T2b-T4, N0)	Every 3-6 months for 2 years, then every 6-12 months for years 3-5	Baseline CT chest/abdomen/pelvis or PET-CT recommended; consider surveillance imaging q6-12 months for 3 years (controversial, no survival benefit proven)	5 years minimum; many patients followed for 10 years or longer due to late recurrence risk (5-10% recur after 5 years)
Stage IIIA-IIID (SLNB positive, any T, N1-N3)	Every 3-6 months for 3 years, then every 6-12 months for years 4-5	Baseline CT or PET-CT recommended; surveillance imaging q6-12 months for 3-5 years (depending on nodal burden, adjuvant therapy receipt)	5-10 years (late recurrences common in stage III)
Stage IV (distant metastasis)	Per medical oncology (varies by therapy, response status)	CT, PET-CT, or MRI every 3-6 months during active treatment; then as clinically indicated	Lifelong (but depends on response to therapy and patient goals)

Sample Clinical Documentation for Melanoma by Breslow Depth

Example 1: T1a melanoma (≤0.8 mm, no ulceration): "Patient is a 45-year-old female with a 0.6 mm Breslow depth melanoma on the left upper back (shave biopsy, subsequently excised). Pathology: Breslow depth 0.6 mm, Clark level II, no ulceration, mitotic rate 0/mm², lymphovascular invasion absent, margins negative. Stage IA (T1aN0M0). Discussed: No sentinel lymph node biopsy recommended (NCCN Category 3, risk of positivity <5%). Wide local excision with 1 cm margins performed (final pathology confirms negative margins). Plan: Clinical skin exam in 6 months, then annually. No imaging. Educated on self-skin exams (ABCDE criteria) and sun protection (SPF 50, avoid tanning beds)." Example 2: T2b melanoma (1.5 mm, ulcerated): "Patient is a 62-year-old male with a 1.5 mm Breslow depth melanoma on the right forearm (excisional biopsy). Pathology: Breslow depth 1.5 mm, ulceration present, mitotic rate 4/mm², Clark level IV, lymphovascular invasion absent, margins negative. Stage T2bN0M0 (stage IIB pending SLNB). Discussed: Sentinel lymph node biopsy is indicated (NCCN Category 1). Patient consents to SLNB. Wide local excision with 2 cm margins scheduled concurrently with SLNB (procedure date [date]). Plan: 1. SLNB with lymphoscintigraphy (right axilla). 2. Wide local excision with 2 cm margins (likely requires skin graft). 3. Post-op: If SLNB negative → stage IIB, annual surveillance. If SLNB positive → stage III, medical oncology referral for adjuvant immunotherapy. 4. Baseline CXR and LDH drawn (normal)." Example 3: T4b melanoma (6.0 mm, ulcerated) with SLNB positive: "Patient is a 70-year-old male with a 6.0 mm Breslow depth melanoma on the left calf (excisional biopsy). Pathology: Breslow depth 6.0 mm, ulceration present, mitotic rate 8/mm², lymphovascular invasion present, microsatellitosis present. Wide local excision with 2 cm margins performed (negative margins). SLNB: 2 of 3 left inguinal lymph nodes positive for metastatic melanoma (largest deposit 3.5 mm). Stage IIIB (T4bN2aM0). Completed staging: CT chest/abdomen/pelvis negative for distant metastasis. Discussed with patient: Adjuvant immunotherapy (pembrolizumab or nivolumab) for 12 months reduces recurrence risk by ~45% (KEYNOTE-054, CheckMate 238). Patient has BRAF wild-type (no targeted therapy). Patient elects to start pembrolizumab. Completion lymph node dissection deferred per patient preference (MSLT-II trial). Plan: 1. Start pembrolizumab 200 mg IV q3 weeks x 12 months. 2. Surveillance: skin exam and LDH q3 months, CT chest/abdomen/pelvis q6 months x 2 years. 3. Refer to physical therapy for lymphedema prevention (left leg)."

Origins & History

Alexander Breslow (1928–1980): The Pathologist Who Revolutionized Melanoma Staging

Dr. Alexander Breslow was born in 1928 in New York City. He earned his medical degree from the University of Geneva School of Medicine (Switzerland) in 1954. He completed his pathology residency at the Massachusetts General Hospital and later joined the faculty at George Washington University in Washington, D.C., where he spent most of his career. In the late 1960s, Breslow recognized that the existing staging system for melanoma—based on Clark's levels of invasion (I-V, describing the anatomical layer of invasion)—had poor inter-observer reliability and did not adequately predict outcomes. Breslow hypothesized that a simple, quantitative measurement of vertical tumor thickness would be more reproducible and prognostic. He studied 98 patients with cutaneous melanoma, measured the thickness in millimeters from the granular layer of the epidermis to the deepest tumor cell, and correlated thickness with 5-year survival. His landmark 1970 paper in *Annals of Surgery* demonstrated that lesions <0.76 mm had 100% 5-year survival, while lesions >2.25 mm had only 25% survival. This simple measurement revolutionized melanoma staging, and within two decades, Breslow depth replaced Clark level as the primary prognostic factor. The AJCC adopted Breslow depth as the T category determinant in the 5th Edition (2001). Dr. Breslow died in 1980 at age 52, but his name remains synonymous with melanoma prognosis.

Key Contributors and Timeline

Year	Contributor(s)	Institution	Contribution
1966	Clark WH, From L, Bernardino EA, Mihm MC	Harvard Medical School / Massachusetts General Hospital	Publication of Clark levels of invasion (I-V) for melanoma. Became the standard prognostic system for the next decade.
1970	Breslow A	George Washington University, Washington, D.C.	Landmark publication demonstrating Breslow thickness (vertical measurement in mm) is superior to Clark level for melanoma prognosis.
1983	Balch CM, Murad TM, Soong SJ, et al.	University of Alabama at Birmingham	AJCC first incorporated Breslow depth (≤0.75 mm, 0.76-1.50 mm, 1.51-3.00 mm, >3.00 mm) in melanoma staging (AJCC 2nd Edition).
2001	AJCC Melanoma Staging Committee (Balch CM, Buzaid AC, Soong SJ, et al.)	Multiple institutions	AJCC 5th Edition: Breslow depth fully replaces Clark level as primary T category determinant. Clark level retained only for T1 melanomas (≤1.0 mm). T categories refined: T1 (≤1.0 mm), T2 (1.01-2.0 mm), T3 (2.01-4.0 mm), T4 (>4.0 mm). Ulceration introduced as upstaging factor.
2006	Morton DL, Thompson JF, Cochran AJ, et al. (MSLT-I)	John Wayne Cancer Institute, Melanoma Institute Australia	MSLT-I validates SLNB for melanoma staging; SLNB positivity rates by Breslow depth established.
2009	AJCC Melanoma Committee (Balch CM, Gershenwald JE, Soong SJ, et al.)	Multiple institutions	AJCC 6th Edition: Mitotic rate introduced as T1 category modifier; T1a (≤1.0 mm, no ulceration, mitotic rate 0/mm²), T1b (≤1.0 mm, ulceration OR mitotic rate ≥1/mm²).
2016-2017	Nikiforov YE, Seethala RR, Tallini G, et al. (for NIFTP)	University of Pittsburgh, Yale University, University of Bologna	NIFTP reclassification (non-invasive follicular thyroid neoplasm with papillary-like nuclear features) — though not melanoma, its principles influenced AJCC's decision to reclassify microsatellites.
2017	AJCC Melanoma Committee (Gershenwald JE, Scolyer RA, Hess KR, et al.)	MD Anderson, University of Sydney, other institutions	AJCC 8th Edition: T1a cutoff reduced to ≤0.8 mm (from ≤1.0 mm). T1b defined as ≤1.0 mm with ulceration OR 0.8-1.0 mm regardless. Mitotic rate removed from T staging (still prognostic). Microsatellites moved from T to N category.
2017	Faries MB, Thompson JF, Cochran AJ, et al. (MSLT-II)	John Wayne Cancer Institute, Melanoma Institute Australia	MSLT-II: Completion lymph node dissection (CLND) does not improve survival for SLNB-positive patients; observation with nodal ultrasound acceptable.
2017-2018	Weber J, Mandala M, Del Vecchio M, et al. (CheckMate 238); Eggermont AM, et al. (KEYNOTE-054)	Multiple international centers	Adjuvant immunotherapy (nivolumab, pembrolizumab) improves recurrence-free survival for stage III melanoma (including T4, any N+). Became standard of care.
2023	NCCN Melanoma Panel (Swetter SM, et al.)	National Comprehensive Cancer Network	NCCN v3.2023 guidelines: SLNB indicated for T1b-T4 (≥0.8 mm); T1a optional with high-risk features. Adjuvant therapy recommended for stage III. Imaging guidelines for stage IIB-IIC updated (baseline, surveillance optional).

Future Directions: Genomics and Precision Medicine

While Breslow depth remains the cornerstone of melanoma staging, genomic profiling is increasingly used for risk stratification. Gene expression profiling (GEP) tests (e.g., DecisionDx-Melanoma, 31-gene expression signature) can classify T1-T2 melanomas as Class 1 (low risk) or Class 2 (high risk) independent of Breslow depth and ulceration. For T1a melanomas (≤0.8 mm, no ulceration), GEP Class 2 identifies a subgroup with higher SLNB positivity risk (~15-20% vs 5% average) who may benefit from SLNB despite guidelines not recommending it. Conversely, GEP Class 1 for T2-T3 melanomas may support less aggressive surveillance. However, GEP is not yet incorporated into AJCC staging or NCCN guidelines (Category 2B evidence, moderate). Other advances: artificial intelligence (AI) for automated Breslow measurement (digital pathology algorithms), circulating tumor DNA (ctDNA) for minimal residual disease detection post-WLE, and multi-omics integration (mRNA, miRNA, proteomics) for recurrence risk prediction. Breslow depth will remain essential, but integrated clinical-molecular models will refine prognostic accuracy.

Last Comprehensive Review: 2026-07-17

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Scanning Medical Journals

No new significant updates or guidelines matching this topic were found today. We will check again soon.

Feature

Breslow Depth

Clark Level

Definition

Vertical tumor thickness in millimeters from granular layer (or ulcer base) to deepest invasive cell

Anatomic level of invasion (I-V) based on dermal layers

Levels/Categories

Continuous variable (0.1 to 20+ mm), categorized into AJCC T categories (T1-T4)

5 ordinal levels: I (intraepidermal), II (papillary dermis), III (papillary-reticular interface), IV (reticular dermis), V (subcutaneous fat)

Inter-observer reliability

High (0.85-0.95 correlation coefficient, precise measurement)

Low to moderate (kappa 0.45-0.65, subjective boundaries of dermal layers)

Prognostic power

Superior (single most important prognostic factor per AJCC)

Inferior (no longer used in AJCC 8th Edition for T staging, but may be reported for historical completeness)

Use in AJCC 8th Edition

Primary determinant of T category (T1-T4 based on thickness and ulceration)

Not used in formal staging (dropped after AJCC 5th Edition in 2001)

Correlation with SLNB positivity

Continuous: 5% (≤0.8 mm), 10-15% (0.8-1.0 mm), 15-25% (1.01-2.0 mm), 30-45% (2.01-4.0 mm), >50% (>4.0 mm)

Clark IV/ V higher risk than Clark II/III, but does not add independent prognostic information after adjusting for Breslow

Clinical utility (2024)

Essential for staging, margins, SLNB decision, and adjuvant therapy

Historical; rarely used in modern clinical decision-making except for T1a classification (≤0.8 mm AND no ulceration AND Clark level IV may upstage to T1b? Controversial; NCCN does not recommend)

T Category

Breslow Depth (mm)

Ulceration Status

Estimated 5-year Survival (Stage I-II)

SLNB Positivity Rate

Management Implications

Tis (in situ)

N/A (no invasion; melanoma confined to epidermis)

Not applicable

~99-100%

<1% (rarely positive)

Wide local excision with 0.5-1.0 cm margins, no SLNB, no adjuvant therapy. Complete excision is curative.

T1a

≤0.8 mm

No ulceration

~99% (similar to Tis)

~5-7% (low, but not zero)

WLE with 1.0 cm margins. SLNB may be considered if mitotic rate ≥1/mm², lymphovascular invasion, or patient young age (but NCCN: discussion for T1b only). Controversial; most guidelines do NOT recommend routine SLNB for T1a.

T1b

≤1.0 mm

Yes (ulceration) OR 0.8-1.0 mm regardless of ulceration

~97-98%

~10-15% (higher if ulcerated)

WLE with 1.0 cm margins. SLNB recommended for discussion (NCCN: consider SLNB for T1b, especially if ulcerated or high mitotic rate). Adjuvant therapy not standard (unless SLNB positive).

T2a

1.01 - 2.0 mm

No ulceration

~93-96%

~15-20%

WLE with 1.0-2.0 cm margins (1 cm acceptable, 2 cm preferred by some). SLNB indicated (NCCN Category 1 recommendation). If SLNB negative, observation. If SLNB positive, complete lymph node dissection or nodal observation (MSLT-II trial), consider adjuvant immunotherapy.

T2b

1.01 - 2.0 mm

Yes (ulceration)

~90-93%

~25-30%

Same as T2a but higher risk; SLNB mandatory. Adjuvant therapy if SLNB positive. Consider baseline imaging (CXR, LDH) due to higher risk.

T3a

2.01 - 4.0 mm

No ulceration

~85-90%

~30-40%

WLE with 2.0 cm margins. SLNB indicated (Category 1). Baseline imaging (CXR, LDH, CT chest/abdomen/pelvis if high-risk symptoms or for clinical trial). Adjuvant therapy if SLNB positive.

T3b

2.01 - 4.0 mm

Yes (ulceration)

~75-85%

~40-50%

Same as T3a but higher risk. Baseline imaging recommended (CT or PET-CT) even if SLNB negative (due to higher distant metastasis risk).

T4a

>4.0 mm

No ulceration

~70-80%

~50-65%

WLE with 2.0 cm margins. SLNB indicated. Baseline imaging required (CT chest/abdomen/pelvis or PET-CT). Consider adjuvant immunotherapy even if SLNB negative? NCCN: For T4 (≥4 mm), consider adjuvant therapy discussion if high risk (ulcerated, positive SLNB, multiple primaries).

T4b

>4.0 mm

Yes (ulceration)

~50-60%

~65-75%

Same as T4a. Very high risk. SLNB mandatory. Baseline imaging required. Strongly consider adjuvant immunotherapy (anti-PD-1, e.g., pembrolizumab, nivolumab) even if SLNB negative (based on extrapolation from stage III trials and high recurrence risk). Clinical trial if available.

Scenario

Measurement Rule

Example

Impact on Staging

Ulcerated melanoma

Measure from the base of the ulcer (tumor-air interface) to the deepest invasive cell

Breslow depth from granular layer would be 2.5 mm, but ulcer base is 0.3 mm lower, so measured depth = 2.8 mm

Higher T category (e.g., T2a → T2b if 1.01-2.0 mm with ulceration; T2b to T3a if crosses 2.0 mm threshold). Higher risk of SLNB positivity.

Satellite tumor nests (within 0.5 mm of main tumor)

Include satellite nests in measurement if within 0.5 mm of deepest invasive front

Main tumor depth 1.5 mm, but separate nest at 2.0 mm within 0.5 mm of main front? Include: measured depth = 2.0 mm

Higher T category (upstages from T2a to T3a if crosses 2.0 mm threshold). Microsatellites beyond 0.5 mm counted separately in N category, not T.

Tumor cells tracking along hair follicle or sweat gland

Include depth of tumor cells along adnexal structures, even if deep

Melanoma cells extend 3.5 mm down a hair follicle (continuous with superficial tumor)

Measured depth = 3.5 mm (T3 if 2.01-4.0 mm). These are not "microsatellites" (they are contiguous).

Desmoplastic melanoma

Measure from granular layer to deepest spindle cell (desmoplastic component)

Superficial epithelioid component 0.8 mm, deep desmoplastic component 4.5 mm

Measured depth = 4.5 mm (T4). Desmoplastic melanoma often underestimated on punch biopsy; need complete excision for accurate measurement.

Thin melanoma with regression

If invasive component is destroyed by regression, measure from granular layer to deepest remaining tumor. If no invasive tumor remains, report as "no measurable Breslow depth; regression only"

Original invasion depth unknown due to lymphocytic infiltrate destroying tumor

Cannot stage accurately; consider complete excision and close clinical follow-up. May be upstaged based on regression thickness? Controversial. AJCC recommends measuring residual tumor only.

Subungual melanoma (nail bed)

Measure from the base of the nail plate (if ulcerated) or from the granular layer of the nail bed epithelium

Subungual melanoma with Breslow depth 2.5 mm

Same T staging as cutaneous melanoma. No specific nail adjustments. Important to report depth for surgical margin decisions (amputation vs wide local excision).

Breslow Depth

Ulceration

Mitotic Rate

SLNB Recommendation

Level of Evidence

Notes

<0.8 mm (T1a)

Any (including 0/mm²)

Not recommended (low yield, <5% positivity)

NCCN Category 3 (no benefit), but some centers discuss for mitotic rate ≥2/mm² or young age

False-negative rate low, but risk of complications (lymphedema, seroma, nerve injury). Observation recommended.

0.8 - 1.0 mm (T1b)

Any (including no ulceration)

Any

Discuss SLNB (NCCN Category 2B)

Positivity rate 10-15%. Consider if patient fit for surgery, high mitotic rate (>2/mm²), young age (<40 years), or patient desires prognostic information.

1.01 - 2.0 mm (T2a/T2b)

Either

Any

SLNB indicated (NCCN Category 1)

Positivity rate 15-30%. Standard of care. If SLNB positive, complete lymph node dissection (CLND) or nodal observation (MSLT-II trial showed no survival benefit for CLND but improved regional control).

2.01 - 4.0 mm (T3a/T3b)

Either

Any

SLNB indicated (NCCN Category 1)

Positivity rate 30-50%. Mandatory. Baseline imaging recommended. Adjuvant therapy (pembrolizumab, nivolumab, dabrafenib/trametinib if BRAF mutant) if SLNB positive.

>4.0 mm (T4a/T4b)

Either

Any

SLNB indicated (NCCN Category 1)

Positivity rate 50-75%. Mandatory. Baseline imaging required. Adjuvant therapy strongly recommended (even if SLNB negative? Controversial; some guidelines recommend for T4b regardless of nodal status due to high recurrence risk).

T Category

Breslow Depth

Recommended Margin (cm)

Evidence Base

Surgical Technique Considerations

In situ (Tis)

N/A

0.5 - 1.0 cm

5-year local recurrence rate <2% with 0.5 cm margin

Standard excision or Mohs micrographic surgery for lentigo maligna (face, scalp, other cosmetically sensitive areas)

T1a (≤0.8 mm, no ulceration)

≤0.8 mm

1.0 cm

1.0 cm margin vs 2.0 cm: no difference in local recurrence (RCT, 1 cm non-inferior)

1 cm margin recommended (less morbidity than 2 cm). Can be performed with primary closure in most anatomic sites.

T1b (≤1.0 mm with ulceration OR 0.8-1.0 mm regardless)

≤1.0 mm

1.0 cm

Same as T1a (extrapolated)

1 cm margin standard. SLNB discussion as above.

T2a/T2b (1.01-2.0 mm)

1.01-2.0 mm

1.0 - 2.0 cm

1 cm margin may be adequate per some trials (Swedish Melanoma Study Group, 1 cm vs 2 cm RCT for 0.8-2.0 mm). NCCN accepts 1 cm or 2 cm.

Many surgeons prefer 2 cm for 1.01-2.0 mm due to lower local recurrence (1-2% vs 3-4% with 1 cm), but no survival difference. 1 cm acceptable for cosmetically sensitive areas (face, scalp, hands, feet).

T3a/T3b (2.01-4.0 mm)

2.01-4.0 mm

2.0 cm

2 cm margin standard (Intergroup Melanoma Surgical Trial, 2 cm vs 4 cm: no difference in survival, lower morbidity with 2 cm)

2 cm margin. May require skin graft or flap for closure. Consult plastic surgery for complex sites.

T4a/T4b (>4.0 mm)

>4.0 mm

2.0 cm

Same as T3 (2 cm vs 4 cm trials included some >4 mm patients, no benefit to wider margins)

2 cm margin. Skin graft often required. Consider preoperative imaging to rule out distant metastasis before surgery (if not already done).

Stage (Based on Breslow and SLNB)

History and Skin Exam Frequency

Imaging Recommendations

Duration of Follow-up

Stage IA (T1a, N0)

Every 6-12 months for 1-2 years, then annually

None routinely (CXR, LDH only if symptoms or high risk)

At least 3-5 years; consider longer for patients <40 years

Stage IB-IIA (T1b-T2a, N0)

Every 6-12 months

None routinely; consider baseline CXR and LDH (optional)

5 years minimum; some guidelines recommend 10 years for high-risk (T2a, young age)

Stage IIB-IIC (T2b-T4, N0)

Every 3-6 months for 2 years, then every 6-12 months for years 3-5

Baseline CT chest/abdomen/pelvis or PET-CT recommended; consider surveillance imaging q6-12 months for 3 years (controversial, no survival benefit proven)

5 years minimum; many patients followed for 10 years or longer due to late recurrence risk (5-10% recur after 5 years)

Stage IIIA-IIID (SLNB positive, any T, N1-N3)

Every 3-6 months for 3 years, then every 6-12 months for years 4-5

Baseline CT or PET-CT recommended; surveillance imaging q6-12 months for 3-5 years (depending on nodal burden, adjuvant therapy receipt)

5-10 years (late recurrences common in stage III)

Stage IV (distant metastasis)

Per medical oncology (varies by therapy, response status)

CT, PET-CT, or MRI every 3-6 months during active treatment; then as clinically indicated

Lifelong (but depends on response to therapy and patient goals)

Year

Contributor(s)

Institution

Contribution

1966

Clark WH, From L, Bernardino EA, Mihm MC

Harvard Medical School / Massachusetts General Hospital

Publication of Clark levels of invasion (I-V) for melanoma. Became the standard prognostic system for the next decade.

1970

Breslow A

George Washington University, Washington, D.C.

Landmark publication demonstrating Breslow thickness (vertical measurement in mm) is superior to Clark level for melanoma prognosis.

1983

Balch CM, Murad TM, Soong SJ, et al.

University of Alabama at Birmingham

AJCC first incorporated Breslow depth (≤0.75 mm, 0.76-1.50 mm, 1.51-3.00 mm, >3.00 mm) in melanoma staging (AJCC 2nd Edition).

2001

AJCC Melanoma Staging Committee (Balch CM, Buzaid AC, Soong SJ, et al.)

Multiple institutions

AJCC 5th Edition: Breslow depth fully replaces Clark level as primary T category determinant. Clark level retained only for T1 melanomas (≤1.0 mm). T categories refined: T1 (≤1.0 mm), T2 (1.01-2.0 mm), T3 (2.01-4.0 mm), T4 (>4.0 mm). Ulceration introduced as upstaging factor.

2006

Morton DL, Thompson JF, Cochran AJ, et al. (MSLT-I)

John Wayne Cancer Institute, Melanoma Institute Australia

MSLT-I validates SLNB for melanoma staging; SLNB positivity rates by Breslow depth established.

2009

AJCC Melanoma Committee (Balch CM, Gershenwald JE, Soong SJ, et al.)

Multiple institutions

AJCC 6th Edition: Mitotic rate introduced as T1 category modifier; T1a (≤1.0 mm, no ulceration, mitotic rate 0/mm²), T1b (≤1.0 mm, ulceration OR mitotic rate ≥1/mm²).

2016-2017

Nikiforov YE, Seethala RR, Tallini G, et al. (for NIFTP)

University of Pittsburgh, Yale University, University of Bologna

NIFTP reclassification (non-invasive follicular thyroid neoplasm with papillary-like nuclear features) — though not melanoma, its principles influenced AJCC's decision to reclassify microsatellites.

2017

AJCC Melanoma Committee (Gershenwald JE, Scolyer RA, Hess KR, et al.)

MD Anderson, University of Sydney, other institutions

AJCC 8th Edition: T1a cutoff reduced to ≤0.8 mm (from ≤1.0 mm). T1b defined as ≤1.0 mm with ulceration OR 0.8-1.0 mm regardless. Mitotic rate removed from T staging (still prognostic). Microsatellites moved from T to N category.

2017

Faries MB, Thompson JF, Cochran AJ, et al. (MSLT-II)

John Wayne Cancer Institute, Melanoma Institute Australia

MSLT-II: Completion lymph node dissection (CLND) does not improve survival for SLNB-positive patients; observation with nodal ultrasound acceptable.

2017-2018

Weber J, Mandala M, Del Vecchio M, et al. (CheckMate 238); Eggermont AM, et al. (KEYNOTE-054)

Multiple international centers

Adjuvant immunotherapy (nivolumab, pembrolizumab) improves recurrence-free survival for stage III melanoma (including T4, any N+). Became standard of care.

2023

NCCN Melanoma Panel (Swetter SM, et al.)

National Comprehensive Cancer Network

NCCN v3.2023 guidelines: SLNB indicated for T1b-T4 (≥0.8 mm); T1a optional with high-risk features. Adjuvant therapy recommended for stage III. Imaging guidelines for stage IIB-IIC updated (baseline, surveillance optional).

Breslow Depth (Melanoma)

When to Use

What is Breslow Depth?

Primary Clinical Applications

Anatomical Principles: How Breslow Depth is Measured

Comparison with Clark Level

AJCC 8th Edition T Categories (2018, updated with data from 13,000+ patients)

How it Works

Step-by-Step Measurement Guidelines (AJCC 8th / CAP Protocol)

Special Measurement Scenarios

Sentinel Lymph Node Biopsy (SLNB) Indications by Breslow Depth (NCCN v3.2023)

Surgical Margins by Breslow Depth (NCCN, AAD, ASDS Guidelines)

Clinical Pearls

Critical Pearl #1: T1a (≤0.8 mm, no ulceration) Has Excellent Prognosis but NOT Zero Risk

Critical Pearl #2: Ulceration Automatically Upstages T Category

Critical Pearl #3: Microsatellitosis Upstages N Category, NOT T Category

Critical Pearl #4: Breslow Depth on Shave vs Punch vs Excisional Biopsy

Common Pitfalls and Errors in Breslow Interpretation

Integrated Risk Calculator (Melanoma Recurrence, SLNB Positivity)

Next Steps

Step-by-Step Clinical Action by Breslow Depth

Surveillance Schedule by Stage (NCCN v3.2023)

Sample Clinical Documentation for Melanoma by Breslow Depth

The Evidence

Original Breslow Publication (1970)

Thickness, cross-sectional areas and depth of invasion in the prognosis of cutaneous melanoma

AJCC 8th Edition Melanoma Staging (2018)

Melanoma staging: Evidence-based changes in the American Joint Committee on Cancer eighth edition cancer staging manual

Sentinel Lymph Node Biopsy Trials

Sentinel-node biopsy or nodal observation in melanoma

Completion dissection or observation for sentinel-node metastasis in melanoma

Adjuvant Therapy Trials for Stage III Melanoma

Adjuvant ipilimumab versus placebo after complete resection of high-risk stage III melanoma (EORTC 18071): a randomised, double-blind, phase 3 trial

Adjuvant nivolumab versus ipilimumab in resected stage III or IV melanoma (CheckMate 238)

Origins & History

Alexander Breslow (1928–1980): The Pathologist Who Revolutionized Melanoma Staging

Key Contributors and Timeline

Future Directions: Genomics and Precision Medicine

In Recent Clinical News

Breslow Depth (Melanoma)

When to Use

What is Breslow Depth?

Primary Clinical Applications

Anatomical Principles: How Breslow Depth is Measured

Comparison with Clark Level

AJCC 8th Edition T Categories (2018, updated with data from 13,000+ patients)

How it Works

Step-by-Step Measurement Guidelines (AJCC 8th / CAP Protocol)

Special Measurement Scenarios

Sentinel Lymph Node Biopsy (SLNB) Indications by Breslow Depth (NCCN v3.2023)

Surgical Margins by Breslow Depth (NCCN, AAD, ASDS Guidelines)

Clinical Pearls

Critical Pearl #1: T1a (≤0.8 mm, no ulceration) Has Excellent Prognosis but NOT Zero Risk

Critical Pearl #2: Ulceration Automatically Upstages T Category

Critical Pearl #3: Microsatellitosis Upstages N Category, NOT T Category

Critical Pearl #4: Breslow Depth on Shave vs Punch vs Excisional Biopsy

Common Pitfalls and Errors in Breslow Interpretation

Integrated Risk Calculator (Melanoma Recurrence, SLNB Positivity)

Next Steps

Step-by-Step Clinical Action by Breslow Depth

Surveillance Schedule by Stage (NCCN v3.2023)

Sample Clinical Documentation for Melanoma by Breslow Depth

The Evidence

Original Breslow Publication (1970)

Thickness, cross-sectional areas and depth of invasion in the prognosis of cutaneous melanoma

AJCC 8th Edition Melanoma Staging (2018)

Melanoma staging: Evidence-based changes in the American Joint Committee on Cancer eighth edition cancer staging manual

Sentinel Lymph Node Biopsy Trials

Sentinel-node biopsy or nodal observation in melanoma

Completion dissection or observation for sentinel-node metastasis in melanoma

Adjuvant Therapy Trials for Stage III Melanoma

Adjuvant ipilimumab versus placebo after complete resection of high-risk stage III melanoma (EORTC 18071): a randomised, double-blind, phase 3 trial

Adjuvant nivolumab versus ipilimumab in resected stage III or IV melanoma (CheckMate 238)

Origins & History

Alexander Breslow (1928–1980): The Pathologist Who Revolutionized Melanoma Staging

Key Contributors and Timeline

Future Directions: Genomics and Precision Medicine

In Recent Clinical News