Body mass index and weight change in relation to triple-negative breast cancer survival
Menée en Chine auprès de 518 patientes atteintes d'un cancer du sein triplement négatif, cette étude de cohorte prospective évalue l'association entre l'indice de masse corporelle, des changements de poids, mesurés avant et après le diagnostic, et la survie des patientes
The aim of this study was to evaluate the influence of body mass index (BMI), weight change on triple-negative breast cancer (TNBC) prognosis in a population-based prospective cohort study. The current analysis included 518 participants diagnosed with TNBC in Shanghai Breast Cancer Survival Study. Weight at 1 year prior to cancer diagnosis, at diagnosis, and at 6, 18 and 36 months after cancer diagnosis and height at 6 months after cancer diagnosis were assessed. Disease-free survival (DFS) and overall survival (OS) were evaluated in relation to BMI and weight change using Cox proportional hazard models. Obesity (BMI ≥ 28.0 kg/m2) at 1-year pre-diagnosis was associated with higher risk of total mortality and recurrence/disease-specific mortality, with multivariate hazard ratios (HRs) of 1.79 (95 % CI 1.06–3.03) and 1.83 (95 % CI 1.05–3.21), respectively. The associations between BMI and TNBC prognosis attenuated over time from pre-diagnosis to post-diagnosis. Compared with stable weight (change within 5 %), weight loss ≥5 % at 18- or 36-month post-diagnosis was related with higher risk of total mortality and recurrence/disease-specific mortality. Respective multivariate HRs were 2.08 (95 % CI 1.25–3.46) and 1.42 (95 % CI 0.77–2.63) for OS, and 2.50 (95 % CI 1.45–4.30) and 2.17 (95 % CI 1.14–4.12) for DFS. However, the association of weight loss and OS/DFS attenuated after excluding patients whose weight was measured after recurrence. Weight gain ≥5 % at 18- or 36-month post-diagnosis was associated with a non-significant increased risk of death. The results showed that obesity pre-diagnosis and weight loss post-diagnosis was inversely associated with TNBC prognosis. Emphasis on maintaining stable weight after cancer diagnosis for TNBC patients may be considered.