Major pathologic response and long-term clinical benefit in hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer after neoadjuvant chemotherapy.

BACKGROUND

The majority of HR+/HER2-breast cancer patients can also achieve long-term survival despite not attaining pCR, indicating limited prognostic value of pCR in this population. This study aimed to identify novel pathologic end points for predicting long-term outcomes in HR+/HER2-breast cancer after neoadjuvant chemotherapy.

METHODS

We analyzed HR+/HER2-breast cancer patients with stage II-III tumors who underwent curative surgery after neoadjuvant chemotherapy from three hospitals. Major pathologic response (MPR), defined as the presence of Miller-Payne grades 3-5 and positive lymph node ratio of ≤10 %, was used as a pathological evaluation indicator. We assessed the association between MPR and event-free survival (EFS) and performed Multivariable Cox regression to identify independent factors associated with EFS.

RESULTS

From January 2010 to December 2020, 386 patients were included in the final analysis. 28 patients (7.3 %) achieved pCR and 118 patients (30.6 %) achieved MPR. The median duration of follow-up was 54.4 months,5-year EFS was 87 % in the MPR group vs. 68 % in the non-MPR group. Multivariate analysis showed that low PR expression, high clinical stage, lower Miller-Payne grades and Positive lymph node ratio were independent poor prognostic factors for EFS (all P values < 0.05). The prognostic effect of MPR remained in multivariable models (hazard ratio (HR), 0.45; 95 % confidence interval (CI), 0.26-0.76; P = 0.008), In non-pCR patients, those who achieved MPR exhibited a similar EFS compared with pCR patients (HR, 2.25; 95 % CI, 0.51-9.84; P = 0.28).

CONCLUSION

MPR may be a novel pathologic end point in HR+/HER2-breast cancer after neoadjuvant chemotherapy, holding greater applicability in the prognosis evaluation than pCR.