Residual Cancer Burden (RCB)
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
* Primary Tumor Bed
* Primary Tumor Bed area (measured in millimeters)
* Includes the largest two dimensions
* Overall Cancer Cellularity (as percentage of area)
* Percentage of cancer that is invasive disease
* Percentage of cancer that is in situ disease
* Lymph nodes
* Number of positive lymph nodes
* 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.
Additional Info
**Source documents:** pathology report, CAP synoptic report
For further information, refer to the **Breast Resection cancer protocol** published by the College of American Pathologists for the AJCC Staging System *Breast*.
Notes
***Any questions regarding this SSDI are to be posted in the AJCC CAnswer Forum***
**Note 1:** **Effective years**
* This SSDI is effective for diagnosis years 2026+.
* For cases diagnosed 2018-2025, this SSDI must be blank.
**Note 2:** **Criteria for coding**
* A surgical resection **must be done** after the completion of Neoadjuvant Therapy to assign codes 0.000-9.999
**Note 3:** **CAP Protocol or Synoptic Pathology Report**
* Only record the information from the CAP Protocol or synoptic pathology report.
Coding Guidelines
1. **Codes 0.000-9.999: Recording the RCB Score**
* Record the Residual Cancer Burden (RCB) score as stated in the synoptic pathology report to the nearest one thousandth.
* **All three digits beyond the decimal point must be filled in.**
* ***Example 1:*** CAP synoptic report states RCB score 3.151
* Code 3.151
* ***Example 2:*** CAP synoptic reports states RCB score is 3.
* Code 3.000
2. **Code X.555: RCB Score not documented**
* Surgical resection is performed, but the RCB Score is not documented in the **post-neoadjuvant surgical pathology report.**
3. **Code X.666: Planned surgical resection is cancelled/not done**
* Patient had complete response to neoadjuvant therapy, and the surgical resection was cancelled.
* Patient had neoadjuvant therapy, didn't complete it and then refused the surgical resection.
* ***Excludes***: Unknown if surgical resection done (see code X.999)
4. **Code X.777: No neoadjuvant therapy**
* ***Excludes***: surgical resection cancelled (code X.666) or unknown if planned surgical resection was performed (code X.999)
* Non-invasive neoplasm (behaviors /0, /1, /2)
* Autopsy only
5. **Code X.999: Unknown**
* Unknown if neoadjuvant therapy administered
* Unknown if planned surgical resection performed after neoadjuvant therapy
* ***Excludes***: surgical resection done, RCB score unknown (code X.555), surgical resection cancelled (code X.666)
Default
X.888
Metadata
SSDI 2026–
| Code |
Description |
| 0.000-9.999 |
0.000 – 9.999 score |
| X.555 |
Neoadjuvant therapy administered and surgical resection performed, RCB Score not documented or unknown
* Results cannot be determined |
| X.666 |
Neoadjuvant therapy administered and planned surgical resection not done |
| X.777 |
No neoadjuvant therapy
Non-invasive neoplasm (behaviors /0, /1, /2)
Autopsy only |
| X.888 |
Not applicable: information not collected for this case
(If this item is required by your standard setter, use of code X.888 will result in an edit error). |
| X.999 |
Unknown if neoadjuvant therapy administered
Unknown if surgical resection performed after neoadjuvant therapy |
| <BLANK> |
Must be blank if diagnosis year is before 2026 |
