A large meta-analysis of breast cancer patients showed that residual cancer burden after neoadjuvant chemotherapy is an accurate long-term predictor of recurrence and survival across all breast cancer subtypes, according to data presented at the 2019 San Antonio Breast Cancer Symposium (SABCS), held Dec. 10–14.
“In recent years, many single-institution studies have shown that residual cancer burden after neoadjuvant chemotherapy can tell us a great deal about a patient’s prognosis after surgery,” said the study’s lead author, W. Fraser Symmans, MD, professor and director of research operations, Department of Pathology, at The University of Texas MD Anderson Cancer Center in Houston. “We undertook this meta-analysis to help determine whether this is true for all subtypes, and how generalizable previous findings might be.”
Symmans explained that residual cancer burden is assessed through several factors, including the size of the primary tumor, the percentage of the tumor that is invasive versus in situ, and the involvement of lymph nodes. A calculator hosted by MD Anderson calculates residual cancer burden index and assigns a classification of pathologic complete response, RCB-I (minimal burden), RCB-II (moderate burden), or RCB-III (extensive burden).
In this study, Symmans and colleagues from the I-SPY Clinical Trials Consortium compiled and analyzed data from 12 cancer centers or clinical trials, representing approximately 5,100 patients. Using mixed effect models, they examined associations between the RCB index and event-free survival (EFS) and distant recurrence-free survival (DRFS).