BOSTON — Postmenopausal women who gained weight during adulthood had an increased risk for endometrial cancer compared with women who maintained a stable weight, according to data from the American Cancer Society’s Cancer Prevention Study II Nutrition Cohort.
Victoria L. Stevens, Ph.D., strategic director of laboratory services at the National Home Office of the American Cancer Society in Atlanta, presented the data at the 10th AACR International Conference on Frontiers in Cancer Prevention Research, held Oct. 22-25, 2011.
Stevens and colleagues investigated whether adulthood weight gain and/or weight cycling, defined as the number of times a woman purposefully lost 10 pounds or more and then later regained the weight, increased the risk for endometrial cancer in postmenopausal women, independent of body mass index (BMI). Weight cycling, commonly referred to as “yo-yo” dieting, had previously been suggested to increase the amount of fat mass relative to lean body mass, according to Stevens.
“Fat tissue is the major source of circulating estrogen in postmenopausal women, and estrogen promotes the development of endometrial cancer,” Stevens said. “Therefore, we hypothesized that weight cycling could be associated with risk for this cancer because women who engage in this behavior may have a higher proportion of fat than noncyclers.”
The researchers collected data from 38,152 women with an intact uterus and who provided information on weight history and weight cycling on a 1992 questionnaire. Between 1992 and 2007, 560 women reported a diagnosis of endometrial cancer.
Overall, the results indicated that there was an almost fourfold increased risk for endometrial cancer in women who had gained 61 pounds or more in that timeframe, compared with women who maintained a stable weight. After adjustment for baseline BMI, the researchers found a twofold increased risk for endometrial cancer.
In addition, after adjustment, the researchers found no association between weight cycling, or yo-yo dieting, and endometrial cancer risk. “Weight gain during adulthood may increase risk for endometrial cancer in postmenopausal women, but weight cycling, which results from unsuccessful attempts to lose weight, does not increase risk for this cancer,” Stevens said.
Future research should address whether the timing of weight gain and weight cycling during specific parts of adulthood, such as early adulthood versus middle age, influences the risk for endometrial cancer and whether weight loss decreases this risk, Stevens said.
“Weight gain during adulthood should be avoided to minimize risk for endometrial cancer,” she said. “Women who have gained weight and are overweight or obese should continue to attempt to lose weight even though most weight loss will not be maintained.”
The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, the AACR is the world’s oldest and largest professional organization dedicated to advancing cancer research. The membership includes 33,000 laboratory, translational and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 90 other countries. The AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants, research fellowships and career development awards to young investigators, and it also funds cutting-edge research projects conducted by senior researchers. The AACR has numerous fruitful collaborations with organizations and foundations in the U.S. and abroad, and functions as the Scientific Partner of Stand Up To Cancer, a charitable initiative that supports groundbreaking research aimed at getting new cancer treatments to patients in an accelerated time frame. The AACR Annual Meeting attracts more than 17,000 participants who share the latest discoveries and developments in the field. Special Conferences throughout the year present novel data across a wide variety of topics in cancer research, treatment and patient care, and Educational Workshops are held for the training of young cancer investigators. The AACR publishes seven major peer-reviewed journals: Cancer Discovery; Cancer Research; Clinical Cancer Research; Cancer Epidemiology, Biomarkers & Prevention; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Prevention Research. In 2010, AACR journals received 20 percent of the total number of citations given to oncology journals. The AACR also publishes Cancer Today, a magazine for cancer patients, survivors and their caregivers, which provides practical knowledge and new hope for cancer survivors. A major goal of the AACR is to educate the general public and policymakers about the value of cancer research in improving public health, the vital importance of increases in sustained funding for cancer research and biomedical science, and the need for national policies that foster innovation and the acceleration of progress against the 200 diseases we call cancer.
In Boston, Oct. 22-25, 2011: