The Association of Local-Regional Control with High Body Mass Index in Women Undergoing Breast Conservation Therapy for Early Stage Breast Cancer
Menée à partir de données portant sur 154 patientes atteintes d'un cancer invasif du sein de stade précoce ou d'un carcinome canalaire in situ traité par radiothérapie entre 1998 et 2010 (âge médian : 60 ans ; durée médiane de suvi : 73 mois), cette étude évalue l'association entre l'indice de masse corporelle des patientes et le contrôle loco-régional de la maladie
Purpose : Obesity, as measured by body mass index (BMI), is a risk factor for distant recurrence and decreased survival in breast cancer. We sought to determine whether BMI correlated with local recurrence and reduced survival in a cohort of predominantly obese women treated with breast conservation therapy.
Methods and Materials : From 1998-2010, 154 women with early stage invasive breast cancer and 39 patients with ductal carcinoma in situ (DCIS) underwent prone whole breast irradiation. Cox proportional hazards regression, Kaplan-Meier methods with log-rank test, and multivariate analysis were used to explore the association of outcomes with BMI.
Results : The median patient age was 60 years, and the median follow-up was 73 months. The median BMI was 33.2 kg/m2; 91% of patients were overweight (BMI≥25 kg/m2) and 69% of patients were clinically obese (BMI≥30 kg/m2). BMI was significantly associated with local-regional recurrence-free interval for invasive and DCIS patients (hazard ratio 1.09, p=0.047), and there was a trend for increased local-regional recurrence with higher BMI (p=0.09) for patients with invasive disease, which was significant when examining BMI above and below the median value of 33.2 (p=0.008). BMI was also significantly associated with decreased distant recurrence-free interval (DRFI; (HR 1.09, p=0.011) and OS overall survival (HR 1.09, p=0.004); this association remained on multivariate analysis (DRFI, p=0.034; overall survival, p=0.0007).
Conclusions : These data suggest that BMI may impact the rate of local-regional recurrence in breast cancer patients. Higher BMI predicted worse distant recurrence-free interval and overall survival. This investigation adds to growing evidence that BMI is an important prognostic factor in early stage breast cancer treated with breast conservation therapy.
International Journal of Radiation Oncology • Biology • Physics , résumé, 2015