The inner lining of the uterus is known as the endometrium. Cancer of the endometrium makes up about 90 percent of uterine cancers. It is the most common gynecologic cancer in the United States, accounting for approximately 40,000 cases annually.
The most common symptom is abnormal vaginal bleeding. In fact, vaginal bleeding in any postmenopausal woman should be considered to be due to endometrial cancer until proven otherwise. Other symptoms include abdominal pain, pain during urination, and pain during intercourse.
Although there is no known cause for this disease, many cases are associated with excess levels of estrogen.
The five-year survival rate for endometrial cancer is high, particularly with early detection and treatment.
Although endometrial cancer is more common in Caucasians, African-Americans often have worse outcomes with the disease.
The following factors are also associated with risk:
- Obesity: The majority of people diagnosed with endometrial cancer at a young age are obese, and some studies have found that being overweight and having low levels of physical activity were strong risk factors for endometrial cancer. The relationship between obesity and cancer may be explained by increased estrogen levels in obese persons.
- Age: Endometrial cancer risk increases with age. It most commonly affects women over 50 years old.
- Estrogen Replacement Therapy: Estrogen therapy in menopausal women increases the risk for endometrial cancer. However, the combined use of estrogen and progestin is not associated with an increased risk.
- Polycystic ovary syndrome
- Prolonged exposure to estrogen: Early onset of menstrual periods, late onset of menopause, and an absence of pregnancies all result in increased estrogen exposure over the course of adult life. This may increase the risk for endometrial cancer.
- Estrogen-secreting tumors or history of an estrogen-responsive cancer (e.g., breast cancer) increase the risk.
Use of birth control pills, multiparity (multiple pregnancies), and exercise are considered protective.
- A medical history and physical examination, including a Pap smear, are the first steps.
- An endometrial biopsy is necessary if there is any possibility of endometrial cancer.
- Further testing, including hysteroscopy, dilation and curettage, or transvaginal ultrasound, may be necessary in some cases when the diagnosis is in doubt.
Surgery, radiation therapy, chemotherapy, and hormone therapy may all be a part of the treatment regimen. Ultimately, a hysterectomy with removal of the entire uterus and ovaries is required in nearly all cases.
Endometrial Cancer: Nutritional Considerations
As with many cancers, the risk for endometrial cancer appears to be associated with greater intakes of foods found in Western diets, including animal products and refined carbohydrates. Risk seems to be lower among women whose diets are high in fruits, vegetables, whole grains, and legumes. The lower risk in persons eating plant-based diets may be related to a reduced amount of free hormones circulating in the blood or to a protective effect of micronutrients found in these diets.
The following factors are under study for possible protective effects:
- Eating less meat and fat: Studies found a 50 percent greater risk for endometrial cancer among women who consumed the greatest amount of processed meat and fish. Consumption of red meat and eggs is also associated with greater risk.
Higher intake of fat, particularly saturated fat, is associated with a 60 to 80 percent increased risk. Some evidence indicates that this association is due to the influence of dietary fat on weight gain and estrogens.
- Fruits, vegetables, whole grains, and legumes: Although findings are limited, evidence suggests that vegetables, fruits, and the nutrients these foods contain (e.g., vitamin C, various carotenoids, folate, and phytosterols) are associated with reduced risk for endometrial cancer - perhaps as much as a 50 to 60 percent lower risk.
An inverse association between whole grain intake and endometrial cancer has been observed. Individuals with the highest intakes of whole grains appear to have the lowest risk, and vice versa. Higher intakes of soy and other legumes are associated with a reduced risk.
Most beans, vegetables, and fruits, and some whole grains have a low glycemic index (a ranking of how carbohydrate-containing foods affect blood sugar; foods with a low glycemic index raise blood sugar only moderately, compared with foods with a high glycemic index). Studies have shown that women whose diets had more low-glycemic-index foods had a lower risk for endometrial cancer, compared with those whose diets had the more high-glycemic-index foods (e.g., sugar and white bread).
- Moderation of alcohol consumption: Outcomes of studies on alcohol intake and risk for uterine cancers are conflicting, with various studies finding no association, a protective effect, or increased risk. Consistently high alcohol intake is associated with an increased risk in young women (under age 50) and in African-American women. Regular alcohol consumption is also associated with higher breast cancer risk.