Endometrial cancer is the most common gynecologic malignancy, with approximately 59,000 cases diagnosed annually,1 and a lifetime risk of approximately 3.1% in the United States.2 Type I endometrial cancer includes tumors with endometrioid histology that are grade 1 or 2. Type II endometrial cancer includes tumors that have grade 3 endometrioid or nonendometrioid histology, including serous, clear cell, mucinous, squamous transitional cell, mesonephric, and undifferentiated tumors.3 Type I endometrial cancer is hormone sensitive, generally stimulated by estrogen and suppressed by progestins.
Endometrial cancer is diagnosed at a mean age of 63 years,4 and only 15% of cases occur before age 50.5 Women with an elevated body mass index (BMI) have a markedly increased risk of both Types I and II endometrial cancer (TABLE).6 Hence, endometrial cancer is highly prevalent in obese postmenopausal women. For these women health interventions that may reduce the risk of developing endometrial cancer include dieting, physical activity, bariatric surgery, and progestin therapy.
Educating patients is a priority
Many women do not know that postmenopausal bleeding is a sign of endometrial cancer. All postmenopausal women should be advised that if they develop vaginal bleeding they need to be evaluated by a clinician.7 Women who are knowledgeable about the link between postmenopausal vaginal bleeding and endometrial cancer can be encouraged to share this information with their postmenopausal friends in order to reach more people with this important information. All obese postmenopausal women should be advised that weight loss and increased physical activity can reduce the risk of developing endometrial cancer.
How weight loss and physical activity affect risk
Intentional weight loss has been reported to reduce the risk of endometrial cancer in postmenopausal women. As part of the Women’s Health Initiative observational study, 36,794 postmenopausal women aged 50 to 79 years with a uterus had their body weight and height measured at entry into the study and after 3 years of follow-up.8 During the 11 years following study entry, there were 566 incident cases of endometrial cancer. Compared with women who had a stable weight, intentional weight loss of ≥5% was associated with a 40% reduction in the risk of endometrial cancer (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.42–0.86). Compared with women who had a stable weight, women who had weight gain ≥10% had an increased risk of endometrial cancer (HR, 1.26; 95% CI, 1.00–1.57).
High levels of physical activity may be associated with a decreased risk of endometrial cancer. In one study, compared with a sedentary lifestyle, higher levels of physical activity were reported to be associated with a decreased risk of endometrial cancer.9
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