The following article features coverage from the 2019 San Antonio Breast Cancer Symposium. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Residual cancer burden (RCB) index after neoadjuvant therapy was prognostic in the long-term for event-free survival (EFS) and distant recurrence-free survival (DRFS) across 4 breast cancer subtypes, according to a multicenter pooled analysis. The results were presented at the 2019 San Antonio Breast Cancer Symposium (SABCS) in San Antonio, Texas.

For the analysis, patient-level data for 5161 patients with breast cancer were pooled from 12 clinical trials, which included centers throughout the world.

Patients with hormone receptor (HR)-negative, HER2-negative disease who achieved a pathologic complete response (pCR) had an 86% 10-year EFS rate, which decreased as RCB index increased: 75% (RCB-I), 61% (RCB-II), and 25% (RCB-III).

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A similar prognostic trend for RCB index was seen among the remaining 3 breast cancer subtypes: HR-negative, HER2-positive disease; HR-positive, HER2-positive disease; and HR-positive, HER2-negative disease.


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Patients with HR-negative, HER2-positive disease who achieved a pCR had a 93% 10-year EFS rate, which decreased as RCB index increased: 85% (RCB-I), 63% (RCB-II), and 60% (RCB-III).

Patients with HR-positive, HER2-positive disease who achieved a pCR had a 91% 10-year EFS rate, which decreased as RCB index increased: 83% (RCB-I), 64% (RCB-II), and 45% (RCB-III).

Patients with HR-positive, HER2-negative disease who achieved a pCR had an 81% 10-year EFS rate, which decreased as RCB index increased: 86% (RCB-I), 69% (RCB-II), and 52% (RCB-III).

Using a mixed effect Cox model, the researchers found that RCB index was prognostic for EFS (hazard ratio [HR], 1.82; 1.73-1.91) and DDFS (HR, 1.86; 1.76-1.97) for the study population overall, and the RCB index continued to be prognostically significant for all breast cancer subtypes. 

“RCB was prognostic in each phenotypic subtype of breast cancer and was independent of pretreatment and clinical pathologic information,” concluded study presenter W. Fraser Symmans, MD, professor and director of research operations in the department of pathology, at the University of Texas MD Anderson Cancer Center in Houston.

“Perhaps most importantly going forward, there is strong potential to calibrate an individual’s RCB index to his or her residual prognostic risk,” Dr Symmans said. 

Read more of Cancer Therapy Advisor‘s coverage of SABCS by visiting the conference page.

Reference

  1. Yau C, van der Noordaa M, Wei J, et al. Residual cancer burden after neoadjuvant therapy and long-term survival outcomes in breast cancer: A multi-center pooled analysis. Oral presentation at: 2019 San Antonio Breast Cancer Symposium; December 10-14, 2019; San Antonio, TX. Abstract GS5-01.