Neoadjuvant chemotherapy for breast cancer: Pathologic response rates but not tumor size, has an independent prognostic impact on survival.

AIM: We investigated the pathologic complete response rates (pCR) and survival outcomes of early breast cancer patients who underwent neoadjuvant chemotherapy (NAC) over 14 years at a French comprehensive cancer center and reported pCR and survival outcomes by tumor subtypes and size. METHODS: From January 2005 to December 2018, 1150 patients receiving NAC were identified. Correlations between cT stage, breast tumor response, axillary lymph node response, pCR, surgery, and outcomes were assessed. pCR was defined as (ypT0/ypTis) and (ypN0/pN0sn). RESULTS: A pCR was reached in 31.7% (365/1150) of patients and was strongly associated with tumor subtypes, but not with tumor size (pretreatment cT category). Luminal-B Her2-negative and triple-negative (TN) subtypes, cN1 status, older age, and no-pCR had an independent negative prognostic value. Overall survival (OS), relapse-free survival (RFS), and metastasis-free survival (MFS) were not significantly different for cT0-1 compared to cT2 stages. In Cox-model adjusted on in-breast pCR and pN status, ypN1 had a strong negative impact (OS, RFS, and MFS: HR = 3.153, 4.677, and 6.133, respectively), higher than no in-breast pCR (HR = 2.369, 2.252, and 2.323). A negative impact of no pCR on OS was observed for cN0 patients and TN tumors (HR = 4.972) or HER2-positive tumors (HR = 11.706), as well as in Luminal-B Her2-negative tumors on MFS (HR = 2.223) and for Luminal-A on RFS (HR = 4.465) and MFS (HR = 4.185). CONCLUSION: Achievement of pCR, but not tumor size (pretreatment cT category), has an independent prognostic impact on survival. These results suggest potential NAC benefits in patients with small tumors (<2 cm), even in absence of clinically suspicious lymph nodes. Residual lymph node disease after NAC is the most powerful adverse prognostic factor.

Neoadjuvant Chemotherapy for Breast Cancer: Evolution of Clinical Practice in a French Cancer Center Over 16 Years and Pathologic Response Rates According to Tumor Subtypes and Clinical Tumor Size: Retrospective Cohort Study.

We examined characteristics trends in early breast cancer patients receiving neoadjuvant chemotherapy (NAC) over a 16-year period. Our primary objective was to analyze variations in tumor stage and subtype over time. Secondary objectives included analyses of type of surgery and pathological response, from January 2005 to May 2021, 1623 patients receiving NAC were identified. Three periods were determined: 2005-2009 (P1), 2010-2014 (P2), 2015-2021 (P3). Correlations between periods and patient features with cT stage, pathological breast and axillary node response, pathological complete response (pCR), and type of surgery were assessed in univariate and multivariate analyses. We observed a significant increase in cT0-1 and N0 stages with periods (from 6.8% at P1 to 21.2% at P3, and from 43.2% at P1 to 55.9% at P3, respectively) and in the proportion of HER2+ and triple negative (TN) subtypes. In a multivariate analysis, a decrease of cT2-3-4 tumors during P3 was observed for HER2+ (OR:0.174; p=0.004) and TN tumors (OR:0.287; p=0.042). In-breast pCR and pCR were observed in 40.8% and 34.4% of all patients, respectively, with strong association with tumor subtypes, but not with tumor size in multivariate analysis (37.0% pCR for cT0-1 tumors, 36.4% for cT2 tumors, 29.1% for cT3 tumors (cT0-1 versus cT≥2; p=0.222)). pCR was negatively associated with cN1 stage (OR:1.499; p<0.001 for cN1 patients compared to cN0). We observed an increase in the proportion of small cT0-1 and N0 stages treated with NAC, especially in HER2+ and TN subtypes. No significant impact of tumor size on pCR rates was found.