An Overview of the Impact of Body Mass Index on Pathological Complete Response Following Neoadjuvant Chemotherapy in Operable Breast Cancer in a Tertiary Care Centre in South India

Objective: The incidence of female breast cancer in the world is 11.7% with a mortality rate of 6.9%. According to Globocon 2020, breast cancer is the most commonly diagnosed cancer (24.5%) and the leading cause of cancer-related death amongst women worldwide. The purpose of this study was to analyze the impact of Body Mass Index (BMI) on pathological complete response (pCR) rates for operable breast cancer after neoadjuvant chemotherapy (NACT). The primary endpoint was to assess histopathological features of the surgical specimen in response to NACT and to investigate the relationship with pre-chemotherapy BMI taking into account the various molecular subtypes of breast cancer. Materials and Methods: Patients with biopsy-proven breast carcinoma who underwent surgery after NACT between January 2017 and May 2021 were included. All patients were initially divided into three groups depending on their pre-chemotherapy BMI. With BMI <22.9 as normal or underweight category, BMI of 23-27.4, was taken as overweight category and BMI >= 27.5 as obese category. Results: The study included 184 patients. Normal weight patients had the highest rate of pCR (75%) and the lowest was seen in the obese category (33.75%). Furthermore, the subtype most likely to achieve pCR was HER2+/ER negative followed by triple negative BC with odds ratios of 3.46 and 2.21, respectively. Conclusion: This retrospective study established that overweight and obese patients suffering from breast carcinoma had a lessened pCR rare following NACT in comparison with those who were under-/normal weight.