Overweight: Is It a Prognostic Factor in Women with Triple-Negative Breast Cancer?

Background: Obesity is associated with poor outcomes in patients with breast cancer expressing hormone receptors, but this association is not well established for triple-negative breast cancer. In this study, we investigated the influence of body mass index (BMI) in triple-negative breast cancer outcomes. Methods: This is a descriptive and analytical retrospective cohort study at the Regional Oncology Center Hassan II-Oujda. We identified 115 patients with triple-negative breast cancer, met the criteria for inclusion, treated between January 2009 and December 2011. The clinicopathological characteristics were collected to assess the association between BMI and overall survival and disease-free survival at 5 years, using the Kaplan-Meier and Cox model. Results: Data analysis focused on 115 patients, 34 patients (28.7%) were normal weight (BMI < 25) and 82 patients (71.3%) were overweight (BMI ≥ 25). The rates of overall mortality and progression at 5 years were 37.4% and 69.6% respectively. After adjusting for clinicopathological variables and menopausal status, overweight was associated with OS (HR: 2.903, 95% CI: 1.551- 5.432, p = 0.001) and DFS (HR:1.899, 95% IC: 1.05 – 3.433, p=0.034) in all patients with triple-negative breast cancer. When stratified by menopausal status, overweight was associated with DFS and OS (HR : 3.242, 95% CI: 1.249 to 8.412, p = 0.016) and (HR : 2.752, 95% CI: 1.267 to 5.978, p = 0.011) respectively in pre-menopausal women. By cons, BMI was not associated with DFS or OS in postmenopausal women. Conclusions: Overweight is an independent prognostic factor for OS and DFS at 5 years in all patients with triple-negative breast cancer, and menopausal status may be a mitigating factor. Premenopausal women with overweight are at greater risk of death and progression than women with normal weight. Once validated, these results should be considered in the development of prevention programs.