The neoadjuvant chemotherapy responses and survival rates of patients with different molecular subtypes of breast cancer.

Objective: The purpose of this study was to evaluate the effect of neoadjuvant chemotherapy (NAC) on the responses and survival rates of patients with different molecular subtypes of breast cancer.

Methods: A retrospective analysis was conducted on 284 breast cancer patients who underwent NAC in our hospital from January 2017 to January 2019. The patients were classified into the Luminal A (n=87), Luminal B (n=78), human epidermal growth factor receptor 2 positive (HER-2, n=66), and triple-negative (TN, n=53) breast cancer subtypes. The Ki67 expressions and clinical prognoses were compared among the patients in the four subtypes.

Results: The complete response (CR) rates were significantly higher in the HER-2 and TN patients than they were in the Luminal A and Luminal B subtype patients (P<0.05). The HER-2 and TN breast cancer patients had significantly higher response rates (RR) than the Luminal B patients (P<0.05). The Ki67 expressions decreased significantly in the patients with the Luminal B, HER-2, and TN subtypes after NAC (P<0.05), with a greater decrease in the Ki67 expressions in the HER-2 and TN subtypes than in the Luminal B subtypes (P<0.05). The Ki67 levels decreased significantly in the patients with CR or PR compared to the stable disease (SD) and progressive disease (PD) patients (P<0.05). The HER-2 patients had remarkably higher distant metastasis rates, compared to the patients with the Luminal A and B subtypes (P<0.05).

Conclusion: Statistical differences were found in the pathological responses and survival rates in the patients with the different molecular subtypes of breast cancer after the NAC treatment. The HER-2 or TN breast cancer patients had higher pathological response rates, which may be closely related to their decreased Ki67 expressions. Interestingly, the HER-2 breast cancer patients also showed a higher distant metastasis rate, which warrants further analysis.