The prognostic and predictive effect of body mass index in hormone receptor-positive breast cancer
Menée à partir de données portant sur 1 781 patientes ménopausées atteintes d'un cancer du sein HR+ et incluses dans un essai évaluant l'efficacité de l'anastrozole (6 versus 3 ans) après un traitement par tamoxifène d'une durée de 2 ou 3 ans (durée médiane de suivi : 13,1 ans), cette étude évalue, en fonction de l'âge des patientes, l'association entre l'indice de masse corporelle et la survie sans maladie
Background : Obesity has been associated with an adverse prognosis and reduced efficacy of endocrine therapy in patients with hormone receptor-positive (HR+) breast cancer (BC). This study determines the prognostic and predictive effect of body mass index (BMI) on the disease-free survival (DFS) of postmenopausal HR+ BC patients.
Methods : Patients were identified from the DATA study (NCT00301457), a randomised controlled trial evaluating the efficacy of six vs three years of anastrozole after two to three years of adjuvant tamoxifen in postmenopausal women with HR+ BC. Patients were classified as normal weight (BMI: 18.5–24.9 kg/m2), overweight (25–29.9 kg/m2), or obese (
≥
30 kg/m2). The primary endpoint was DFS, evaluated from randomisation (prognostic analyses) or three years after randomisation onwards (predictive analyses; aDFS) using multivariable Cox regression analyses. P-values were two-sided.
Results : This study included 678 normal weight, 712 overweight, and 391 obese patients. After a median follow-up of 13.1 years, overweight and obesity were identified as negative prognostic factors for DFS (hazard ratio (HR)=1.16; 95% confidence interval (CI): 0.97-1.38 and HR = 1.26; 95% CI 1.03-1.54, respectively). The adverse prognostic effect of BMI was observed in women aged <60 years, but not in women aged
≥
60 years (p-interaction = 0.009). The effect of extended anastrozole on aDFS was similar in normal weight (HR = 1.00; 95% CI 0.74-1.35), overweight (HR = 0.74; 95% CI 0.56-0.98), and obese patients (HR = 0.97; 95% CI 0.69-1.36)(p-interaction = 0.24).
Conclusion : In this study among 1,781 HR+ BC patients, overweight and obesity were adverse prognostic factors for DFS. BMI did not impact the efficacy of extended anastrozole.
JNCI Cancer Spectrum , article en libre accès, 2022