45P - Demographic determinants of pathological complete response after neoadjuvant chemotherapy in breast cancer

Background

Pathologic complete response (pCR) is often utilized as a surrogate marker for overall survival in breast cancer. Significant differences in pCR rates are reported in many studies depending on the biological tumor profile and molecular classification. Based on our observations we hypothesize that few breast cancer patients are less likely to achieve pCR after neoadjuvant chemotherapy (NACT). The role of demographic variables in predicting pCR is still not clear. The aim of this study was to evaluate various demographic factors which could impact pCR rates.

Methods

A prospective analysis of 1246 patients with breast carcinoma who had undergone neoadjuvant chemotherapy (NACT) followed by surgery was done from June 2020 to December 2022. Demographic, surgical, and pathological data were collected on completion of therapy. Categorical variables were analyzed using χ2 or Fisher’s exact test and continuous data were analyzed using t-tests. Multiple linear regressions were used to study interactions between various demographic factors and pCR. Statistical analysis was done using SPSS v25.

Results

A total of 1324 patients were offered NACT, of which 1246 (94.1%) who underwent resection post-NACT were included in the analysis. Overall, 275 (22.1%) patients had pCR. 39 (14.2%) in ER+/HER2- group, 131 (47.6%) in HER2+ group; and 105 (38.2%) in ER-/HER2- group had pCR. Univariate analysis showed significant association between age <50 years, low body-mass index, and ability to achieve pCR. However, women with obesity had higher odds of residual disease (OR = 0.191 [0.029-1.157]; p=0.076). The results were consistent even after controlling for confounding variables such as grade, receptor status, and clinical T and N stages.

Conclusions

Younger age can predict a pCR and is an independent prognostic factor for locoregional recurrence in locally advanced breast cancer patients after NACT. Obesity is a risk factor for failure to achieve PCR in women undergoing NACT. The contrary was observed in non-obese patients as they had higher odds of achieving PCR. Studies with larger groups are needed to validate this observation. Further studies evaluating the role of BMI in drug resistance would be valuable.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

The author has declared no conflicts of interest.