Tamirisa, Nina

Neoadjuvant chemotherapy (NAC) increases rates of successful breast-conserving surgery (BCS) in patients with breast cancer. However, some studies suggest that BCS after NAC may confer an increased risk of locoregional recurrence (LRR). We assessed LRR rates and locoregional recurrence-free survival (LRFS) in patients enrolled on I-SPY2 (NCT01042379), a prospective NAC trial for patients with clinical stage II to III, molecularly high-risk breast cancer. Cox proportional hazards models were used to evaluate associations between surgical procedure (BCS vs mastectomy) and LRFS adjusted for age, tumor receptor subtype, clinical T category, clinical nodal status, and residual cancer burden (RCB). In 1462 patients, surgical procedure was not associated with LRR or LRFS on either univariate or multivariate analysis. The unadjusted incidence of LRR was 5.4% after BCS and 7.0% after mastectomy, at a median follow-up time of 3.5 years. The strongest predictor of LRR was RCB class, with each increasing RCB class having a significantly higher hazard ratio for LRR compared with RCB 0 on multivariate analysis. Triple-negative receptor subtype was also associated with an increased risk of LRR (hazard ratio: 2.91, 95% CI: 1.8–4.6, P < 0.0001), regardless of the type of operation. In this large multi-institutional prospective trial of patients completing NAC, we found no increased risk of LRR or differences in LRFS after BCS compared with mastectomy. Tumor receptor subtype and extent of residual disease after NAC were significantly associated with recurrence. These data demonstrate that BCS can be an excellent surgical option after NAC for appropriately selected patients.

Objective: To determine whether the association between overall survival (OS) and response to neoadjuvant chemotherapy (NACT) in breast cancer patients varies with tumor subtype and anatomic extent of pathologic complete response (pCR). Background: pCR after NACT predicts improved OS in breast cancer, but it is unclear whether pCR limited to the breast or axilla is also associated with OS. Methods: Women with cT1-3/cN0-1 breast cancer diagnosed in 2010 to 2014 who underwent surgery following NACT were identified in the NCDB and divided into 4 subtypes based on reported hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status. Kaplan-Meier curves and Cox proportional hazards models were used to estimate OS. Multivariate logistic regression was used to identify factors associated with post-NACT response, defined as upstage (yp stage>clinical stage); no change (clinical stage = yp stage); overall (breast+axilla, ypT0N0), breast-only (ypT0N1/N1mic), or node-only (ypT1-3N0) pCR. Results: Of 33,162 identified patients, 20,265 experienced overall pCR (n = 6370, 19.2%), breast-only pCR (n = 494, 1.5%), node-only pCR (n = 1133, 3.4%), no stage change (n = 9641, 29.1%), or upstage (n = 2627, 7.9%). Compared with no stage change, breast-only pCR was associated with improved OS in triple-negative disease [hazard ratio = 0.58, 95% confidence interval (95% CI) = 0.37–0.89], and node-only pCR was associated with improved OS in both triple-negative (hazard ratio = 0.55,95% CI = 0.39–0.76) and HR+/HER2− disease (hazard ratio = 0.54, 95% CI = 0.33–0.89). For patients achieving overall (breast+axilla) pCR, unadjusted 5-year OS was 0.94 (95% CI = 0.93–0.95), with no difference between patients who were cN0 (hazard ratio = 0.95, 95% CI = 0.93–0.96) or cN1 (hazard ratio = 0.94, 95% CI = 0.92–0.96) at diagnosis. Conclusions: In node-positive patients, pCR limited to either the breast or axilla predicts survival for select receptor subtypes. In patients achieving pCR in both the breast and axilla, survival is driven by response to NACT rather than presenting cN stage.