Effect of obesity on the survival outcomes among Indian women with breast cancer.

Abstract

e12558 Background: Studies have reported increased risk of breast cancer (BC) with obesity in Indian population and few studies also highlighted the association of Body Mass Index (BMI) with BC types and chemotherapy response. However, no study till date has reported the effect of obesity on the survival outcomes among Indian women with BC. Methods: We retrospectively analyzed the medical records of women registered at our institute with a diagnosis of BC between years 2013-2024. Along with demographic, clinical and tumor characteristics, baseline weight and height were retrieved from the medical records. Primary outcomes were disease-free survival (DFS) and overall survivals (OS). Cox-regression and Kaplan-Meier survival analysis were used to examine the association of BMI with survival outcomes. Results: Study sample consisted of 1303 women with BC. Median age of the study cohort is 46years and 42% were postmenopausal. Fifty-one percent of the cases were Hormone receptor (HR) positive and Her2Neu negative, followed by 29.4% (HR+ and Her2Neu+), 14.5% (TNBC) and 5.3% (HR- and Her2Neu+). AJCC-Stage I & II tumors consisted of 42.6%, followed by 41.1% Stage-III and 16.3% Stage IV tumors. Forty-one percent were obese (BMI>27.5kg/m 2 ) and 35% were overweight (BMI: 23-27.5kg/m 2 ). Fifty percent of postmenopausal women were obese at time of presentation compared to 34.5% of premenopausal women (p<0.001). Proportions of those with ECOG score ≥2 and with one or more comorbidity were significantly high among obese group compared to other BMI categories (p<0.05). Family history of cancer, clinical stage, HR/Her2Neu receptor status and type of surgery received did not vary across the BMI categories. Median DFS for overweight (110 months) and obese (107.2 months) individuals was significantly lower compared to normal/underweight individuals (194 months). After adjusting for menopausal status, comorbidity, clinical stage and receptor status; BMI≥27.5 was significantly associated with poor DFS [aHR(95%CI):1.78(1.25-2.55), p=0.002]. Premenopausal status, Stage>II and ECOG score≥2 were associated with poor DFS. Among those with non-metastatic breast cancer at time of presentation, BMI≥27.5 was associated with poor overall survival [aHR(95%CI):1.91(1.01-3.63), p=0.047], however, BMI was not associated with overall survival among those who with metastatic breast cancer. The effect of BMI on the survival outcomes didn’t vary by menopausal status and receptor status. Conclusions: BMI is independent predictor of survival among Indian women with BC. Clinical trials with multimodal therapeutic approaches including nutritional and lifestyle interventions are required to improve the survival outcomes among obese women with BC.