Association of Obesity With Breast Cancer Outcome in Relation to Cancer Subtypes: A Meta-Analysis

Abstract

Background Obesity at breast cancer (BC) diagnosis has been associated with poor outcome, although the magnitude of effect in different BC subtypes is uncertain. We report on the association of obesity/overweight at diagnosis of non-metastatic BC with disease-free (DFS) and overall survival (OS) in the following defined subtypes: hormone receptor positive/HER2 negative (HR+HER2-), HER2 positive (HER2+), and triple negative (TNBC). Methods We searched MEDLINE, EMBASE and COCHRANE databases until January 1, 2019. Study eligibility were performed independently by two authors. Studies reporting hazard ratios (HR) of OS and/or DFS for obesity/overweight in BC subtypes were included. Pooled HR were computed and weighted using generic inverse variance and random effects models. Results 27 studies were included. Obese, compared to non-obese, women, had worse DFS in all subtypes: the hazard ratios were 1.26 (95% confidence interval [CI] = 1.13 to 1.41, P < .001) for HR+HER2-BC, 1.16 (95%CI = 1.06 to 1.26, P < .001) for HER2+ BC, and 1.17 (95%CI = 1.06 to 1.29, P = .001) for TNBC. OS was also worse in obese vs non-obese women (HR+HER2-BC HR = 1.39, 95%CI = 1.20 to 1.62, P < .001; HER2+BC HR = 1.18, 95%CI = 1.05 to 1.33, P = .006 and TNBC HR = 1.32, 95%CI = 1.13 to 1.53, P < .001). As opposed to obesity, overweight was not associated with either DFS or OS in HER2+BC (HR = 1.02, 95%CI = 0.81 to 1.28, P = .85; and HR = 0.96, 95%CI = 0.76 to 1.21, P = .99, respectively) or TNBC (HR = 1.04, 95%CI = 0.93 to 1.18, P = .49; and HR = 1.08, 95%CI = 0.81 to 1.44, P = .17), respectively. In HR+HER2-BC, being overweight was associated with worse OS (HR = 1.14, 95%CI = 1.07 to 1.22, P < .001). Conclusions Obesity was associated with modestly worse DFS and OS in all BC subtypes.

Overweight and prognosis in triple-negative breast cancer patients: a systematic review and meta-analysis

“…However, this needs to be further addressed in future studies and the results from Ballinger et al, should be interpreted with caution as they are limited by the small population of 172 chemoresistant TNBC patients with residual disease and the short follow-up time (primary endpoint is two year DFS). Furthermore, in a recent metaanalysis evaluating all breast cancer subtypes, obesity (BMI ≥ 30 kg/m 2 ), however not overweight (BMI 25-30 kg/m 2 ), was reported to influence prognosis in TNBC patients 43 . Compared to this meta-analysis, the partly different results by Lohmann, et al, may be explained by their inclusion of observational studies with heterogeneous BMI comparator groups, heterogeneous endpoints and interventional cohorts.…”

Harnessing Nutrition and Physical Activity for Breast Cancer Prevention and Control to Reduce Racial/Ethnic Cancer Health Disparities

“…Although the evidence tends to be stronger for hormone receptor + breast cancer, a recent metaanalysis found that obesity was associated with worse diseasefree survival and overall survival for all subtypes, including HER2 + and triple-negative breast cancer. 51 The effect of central adiposity, measured as waist-to-hip ratio or waist circumference, on breast cancer mortality has received little attention, but a meta-analysis based on four studies found elevated mortality for those with high waist-to-hip ratio. 11 Weight changes after diagnosis are particularly important among survivors.…”

A Precision Medicine Approach to Metabolic Therapy for Breast Cancer in Mice

“…These data suggest that precision medicine approaches to neoadjuvant treatment are of pressing importance. Indeed, a recent meta-analysis hinted at a differing effect of obesity on outcomes based on cancer subtype: Lohmann and colleagues observed a larger magnitude of the deleterious effect of excess body weight in triple-negative and hormone receptor-positive, HER2-negative breast cancer as compared to hormone receptorpositive, HER2-positive breast cancer (39). However, these data stop short of suggesting specific breast cancer driver mutations that may be more or less responsive to therapies aiming to reduce circulating insulin concentrations.…”