NAACCR Item #1178: Residual Cancer Burden (RCB)

Item # Length Source of Standard Year Implemented Version Implemented Year Retired Version Retired
1178 5 NAACCR 2026 26
NAACCR XML: Tumor.residualCancerBurdenRCB
Description
Residual Cancer Burden (RCB) is a score that measures the amount of cancer remaining in the breast and the regional lymph nodes after neoadjuvant therapy and surgical resection. The RCB score is based on 4 independent prognostic factors measuring the primary tumor bed and 2 independent factors measuring the lymph nodes.  The RCB score combines these 6 independently prognostic factors from the surgical specimen after neoadjuvant therapy into a single continuous score. This score is prognostic across breast cancer subtypes, different treatments, and within existing stage groups.  The independent prognostic factors include 1. Primary Tumor Bed 1. Primary Tumor Bed area (measured in millimeters) 1. Includes the largest two dimensions 2. Overall Cancer Cellularity (as percentage of area) 3. Percentage of cancer that is invasive disease 4. Percentage of cancer that is in situ disease 2. Lymph nodes 1. Number of positive lymph nodes 2. Diameter of largest metastasis
Rationale
Neoadjuvant therapy is now standard of care for HER2+ and triple negative breast carcinoma. Quantification of residual disease after neoadjuvant therapy determines further patient management in this setting. The Residual Cancer Burden (RCB) is the most validated measure of volume of residual disease post neoadjuvant for breast cancer and has prognostic value.
Codes
0.000-9.999 0.000 – 9.999 score
X.777 Patient had neoadjuvant therapy, but not a post neoadjuvant surgical resection. Patient did not have neoadjuvant therapy.
X.888 Not applicable: information not collected for this case (If this item is required by your standard setter, use of code X.8 will result in an edit error).
X.999 Post neoadjuvant surgery completed and RCB burden not documented in CAP Protocol or synoptic pathology report. Post neoadjuvant surgery completed and surgical pathology report not available.
Blank Must be blank if diagnosis year is before 2026.