Assessment of the prognostic role of body mass index on breast cancer survivors: A Moroccan center experience

Abstract

Positive association between elevated body mass index (BMI) and reduced survival in breast cancer (BC) women was demonstrated in previous meta-analyses of published data. Meanwhile, recent studies have reported that low BMI was associated with BC recurrence and overall mortality, which is paradoxical. The aim of our study was to evaluate the impact of BMI on mortality risk in a population of BC survivors. This retrospective study included 2284 female BC survivors recruited from the registry of the cardio-oncology unit of Casablanca between 2014 and 2021. BMI defined by the WHO criteria as follow: underweight (UW; BMI < 18.5 kg/m 2 ), normal weight (NW; BMI = 18.5–24.9 kg/m 2 ) and overweight or obese (OW; BMI ≥ 25 kg/m 2 ). We performed to evaluate the association between low BMI and clinical outcome in BC patients. The clinicopathological characteristics and clinical outcomes of patients after BC diagnosis were analyzed. In our study, 9.2% patients were UW and 23.9% were OW. OW group was associated with older age, larger size tumors, and higher cardiotoxicity ( P = 0.032, 0.025, P < 0.001, respectively). The overall survival (OS) decreased in OW patients ( P = 0.014), and both OW and obesity were independent predictors for increased risks of BC relapse and death ( P = 0.028). On the other hand, UW was more prominent in young women ( P = 0.018) and no significant association was found between BC recurrence rate and the UW group ( P = 0.082 and 0.056, respectively). However, multivariate regression analysis found that low BMI was an independent OS prognostic factor in young patients [HR: 1.72 (95% CI: 1.18–2.32), P = 0.029]. Our results demonstrate the prognostic role of BMI on BC survivors that might depend on patients’ age and clinical stage. Both overweight and underweight might be independently associated with poorer prognosis in BC patients. Efforts should be made to maintain BC patients in normal weight in order to improve survival.