PathologyMD Anderson Residual Cancer Burden Index
Primary Tumor Bed
mm
mm
%
Area of tumor bed with invasive cancer
Lymph Node Status
count
Number of involved nodes
mm
Diameter of largest nodal met
Awaiting Data
Please enter tumor bed measurements and nodal status from the surgical pathology report to calculate the RCB index.
Guidelines & Evidence
Verified
Last Review: 2026
When to Use
When to Use RCB Scoring
Post-neoadjuvant chemotherapy (NACT) breast cancer patients (any subtype: HR+/HER2-, HER2+, triple-negative breast cancer (TNBC)) who underwent surgical resection (mastectomy or lumpectomy)
Predicting long-term outcomes: distant relapse-free survival (DRFS), breast cancer-specific survival (BCSS), and overall survival (OS) based on residual disease burden
Risk-stratifying patients beyond pCR (pathologic complete response) — pCR (RCB-0) vs non-pCR (RCB-I, II, III) — to guide adjuvant therapy escalation
Decision-making for adjuvant therapy: (1) TNBC: RCB-II/III → adjuvant capecitabine or pembrolizumab; (2) HER2+: RCB > 0 (non-pCR) → adjuvant T-DM1 (ado-trastuzumab emtansine); (3) HR+/HER2-: RCB-II/III → consider adjuvant abemaciclib (CDK4/6 inhibitor) or extended endocrine therapy
Clinical trial stratification: RCB class as entry criterion or stratification factor (e.g., CREATE-X, KATHERINE, PENELOPE-B trials used RCB or similar residual disease definitions)
Patient counseling: communicating recurrence risk quantitatively (e.g., "Your RCB score of 3.2 (RCB-III) gives a 5-year distant recurrence risk of approximately 45%, so we recommend adjuvant capecitabine to reduce this risk to 30%")
Comparing surgical pathology between centers: standardized quantification of residual disease for quality assurance
Research endpoint: RCB as continuous variable or categorical class (0, I, II, III) in neoadjuvant therapy trials (more sensitive than pCR alone)
RCB vs pCR (Pathologic Complete Response) — Why RCB Is Superior
| Parameter | pCR (ypT0/is ypN0) | RCB Class (0-III) | Advantage of RCB |
|---|---|---|---|
| Definition | No residual invasive cancer in breast or lymph nodes (in situ allowed). Binary (yes/no). | Continuous score (0-5) with 4 classes (0, I, II, III) based on primary tumor dimensions, cellularity, nodal burden. | Continuous index captures gradations of residual disease (e.g., minimal vs extensive), not just binary. |
| Prognostic discrimination | pCR vs non-pCR (poor vs good, but non-pCR heterogeneous). 5-year DRFS: pCR 85-90%, non-pCR 55-75% (varies widely by subtype and burden). | 5-year DRFS: RCB-0 86-92%, RCB-I 75-85%, RCB-II 55-70%, RCB-III 25-45% (stepwise gradient). | RCB-III identifies ultra-high-risk patients (45% recurrence at 5 years) who benefit most from adjuvant escalation; RCB-I identifies good-prognosis non-pCR (similar to pCR for some subtypes). |
| Treatment escalation guidance | Non-pCR (any burden) often receives escalation (e.g., capecitabine for TNBC, T-DM1 for HER2+). May overtreat low-burden non-pCR. | RCB-I (minimal residual) may NOT need escalation (e.g., TNBC RCB-I: 5-year DRFS 82% without capecitabine, similar to pCR 86%). RCB-II/III (moderate-extensive) benefit from escalation. | RCB-I avoids overtreatment (capecitabine toxicity: hand-foot syndrome, diarrhea, fatigue). |
| Subtype interaction | pCR predicts better outcomes across all subtypes, but magnitude varies (TNBC/HER2+ pCR more prognostic than HR+/HER2- pCR). | RCB class prognostic within each subtype, but thresholds differ (e.g., RCB-II for TNBC worse than RCB-II for HR+/HER2-). | Subtype-specific RCB cutoffs (see below). |
When RCB Is Not Applicable (Limitations)
No neoadjuvant therapy (surgery first) — RCB defined only after NACT. For surgery-first, use standard pathologic staging (ypTNM not applicable, use pTNM).
Neoadjuvant endocrine therapy alone (not chemotherapy) — RCB validated in chemotherapy ± targeted therapy, not endocrine therapy (different biology).
Incomplete surgical resection (positive margins) — RCB requires complete resection; positive margins complicate interpretation (residual disease at margin = RCB-III? not validated).
Metastatic disease at presentation (stage IV) — RCB for early-stage (I-III) only; metastatic disease managed differently (systemic therapy indefinitely).
Lack of pathological assessment of primary tumor bed (e.g., grossing error, no tumor bed identified) — RCB requires careful macroscopic and microscopic exam by breast pathologist.
Neoadjuvant radiation therapy (rare) — RCB not validated after radiation (alters cellularity and fibrosis).
Related Scores in Practice
In clinical practice, this assessment is frequently evaluated alongside other validated measures. Depending on the patient's presentation and specific diagnostic requirements, you may also need to utilize the Tnm 8th Ed Breast Prognostic, PREDICT v3.0 or the Oncotype DX Recurrence to formulate a comprehensive care plan.
Last Comprehensive Review: 2026