AACR Obesity and Cancer Conference: Breast Cancer Risk in Postmenopausal Women With Normal BMI
Posted: Tuesday, January 30, 2018
New research shows that higher body fat levels in postmenopausal women with a normal body mass index (BMI) may be associated with an increased risk for invasive breast cancer. This finding, which may be surprising to both physicians and patients, was presented by Neil Iyengar, MD, of Memorial Sloan Kettering Cancer Center, at the 2018 American Association for Cancer Research (AACR) Special Conference on Obesity and Cancer: Mechanisms Underlying Etiology and Outcomes (Abstract PR06) in Austin, Texas.
“While BMI may be a convenient method to estimate body fat, it is not an exact way to determine whole-body fat levels, as muscle mass and bone density cannot be distinguished from fat mass,” stated coauthor Thomas Rohan, MBBS, PhD, DHSc, of the Albert Einstein College of Medicine in Bronx, New York, in a press release.
The study focused on 3,460 postmenopausal women with a normal BMI (18.5 to < 25.0 kg/m2) from the Women’s Health Initiative with baseline dual energy x-ray absorptiometry and no history of breast cancer. A total of 182 participants developed invasive breast cancer during the median 16 years of follow-up; of these women, 146 had estrogen receptor–positive disease.
The investigators found that the risk of estrogen receptor–positive breast cancer increased by 35% for each 5-kg increase in whole-body fat despite a normal BMI. The multivariable-adjusted hazard ratio for invasive breast cancer in the highest versus lowest quartile of whole-body fat mass and trunk fat mass was 1.70 and 1.75, respectively. The adjusted hazard ratio for estrogen receptor–positive breast cancer in the highest versus lowest quartiles of whole-body fat mass and trunk fat mass was 2.10 and 1.91, respectively.
