Abstract: Objective To evaluate the impact of the prognostic nutritional index (PNI) on the prognosis of the breast cancer patients receiving neoadjuvant chemotherapy (NAC). Methods A single-center, retrospective cohort study was performed on the breast cancer patients, who underwent NAC and surgical resection in Internal Medicine-Oncology Beijing Shijitan Hospital Affiliated to Capital Medical University from January 2008 to December 2017, were selected as the research subjects, and the follow-up was as of December 2020. The main study endpoint was the disease-free survival. The cut-off values of PNI before NAC (pre-PNI), PNI after NAC (post-PNI), and PNI before and after NAC (ΔPNI) were calculated by the time-dependent ROC curve. The association between PNI and disease-free survival was analyzed by Cox proportional hazard regression. Results A total of 131 patients met the criteria. The post-PNI was lower than pre-PNI (46.4±4.5 vs 52.5±4.2, P<0.001). The cut-off value of ΔPNI was 5.26. The disease-free survival rate of the high ΔPNI group was significantly lower than that of the low ΔPNI group (P<0.001). Further multivariable Cox proportional hazard regression showed that ΔPNI, pre-NAC clinical stage, and HER-2 were independent influencing factors of the disease-free survival (all P<0.05). Conclusions The decrease in PNI during NAC indicates a poor prognosis. Maintaining a nutritional status during NAC may yield better treatment results for the breast cancer patients.

Key words: Breast cancer, Prognostic nutritional index, Neoadjuvant chemotherapy, Disease-free survival