Intentional Weight Loss Linked to Lowered Endometrial Cancer Risk

Intentional weight loss can lower the risk of endometrial cancer in postmenopausal women, according to a new study. This was especially true of obese women who lost weight.

“Although endometrial cancer is the cancer most strongly associated with obesity, information about the effects of weight loss in postmenopausal women on subsequent endometrial cancer incidence is limited,” wrote study authors led by Juhua Luo, PhD, of Indiana University in Bloomington. Previous work has suggested that unintentional weight loss can be associated with increased morbidity, but most studies have not looked into the influence of intentionality.

The new study included 36,794 women included in the Women’s Health Initiative; all were aged 50 to 79 years at enrollment, and body weight and body mass index (BMI) were calculated at baseline and at year 3. Stable weight indicated no more than 5% gain or loss, while loss and gain referred to 5% or more from baseline; a self-report at year 3 determined intentionality of weight change, and this was correlated with risk of endometrial cancer diagnosis. The results were published online ahead of print in the Journal of Clinical Oncology.

Over a mean follow-up period of 11.4 years, 566 women were diagnosed with endometrial cancer. After adjustment for baseline BMI and other factors, women who had weight loss of 5% or greater had significantly lower risk for endometrial cancer than women with stable weight, with a hazard ratio of 0.71 (95% CI, 0.54–0.95). This was more pronounced among women whose weight loss was deemed intentional; in those women, the HR for endometrial cancer was 0.60 (95% CI, 0.42–0.86).

The effect was strongest in women who were obese (BMI ≥ 30 kg/m²) at baseline. In those women who intentionally lost at least 5% of their body weight the HR for endometrial cancer was 0.44 (95% CI, 0.25–0.78). There was no significant effect seen in normal weight or overweight individuals.

There was an increased risk for the malignancy in women with a weight gain of at least 10 pounds who had not received hormone therapy, but not in those who had.

“These findings should motivate programs for weight loss in obese postmenopausal women,” the authors concluded.

Jennifer Ligibel, MD, an American Society of Clinical Oncology (ASCO) expert at Dana-Farber Cancer Institute who was not involved in the study, agreed in a press release that this would support the development of weight loss programs as part of a cancer prevention strategy. “There have been more than a thousand studies linking obesity to an increased risk of endometrial and other cancers, but almost none that look at the relationship between weight loss and cancer risk,” she said. “This study tells us that weight loss, even later in life, is linked to a lower risk of endometrial cancer.”