Endometrial cancer is the most common type of uterine cancer accounting fro about 95 percent of cases. It starts in the endometrium, the inner lining of a woman's uterus (womb). Almost all cancers of the uterus start in the epithelial cells that line the endometrium and are called endometrial carcinomas. A small number of endometrial cancers are sarcomas, meaning they start in tissues such as muscle, fat, bone, and fibrous tissue. Carcinomas that start in the cervix – the bottom part of the uterus – are called cervical carcinomas.
Endometrial cancer is slow to develop and rare in women under the age of 40. Most cases are found in women aged 50 and over, with more than half diagnosed in women aged 50 to 69. The average chance of a woman being diagnosed with this cancer during her lifetime is about one in 40.
Hormonal imbalance may be the biggest risk factor. A healthy endometrium depends on the right balance between estrogen and progesterone. A shift in that balance toward more estrogen increases a woman's risk for developing endometrial cancer.
Factors that may affect hormonal balance are: aging; using estrogen therapy to treat menopausal symptoms; having a higher than average number of lifetime menstrual cycles; never becoming pregnant; eating a high-fat diet, and being obese and/or diabetic (because fat tissue can change some other hormones into estrogens); and taking Tamoxifen (because it acts like an estrogen in the uterus).
Some inherited traits also increase the risk for endometrial cancer, including: certain ovarian tumors or polycystic ovarian syndrome (PCOS); hereditary nonpolyposis colon cancer (HNPCC or Lynch syndrome); endometrial hyperplasia; and having had previous breast or ovarian cancer along with radiation.
About 90 percent of endometrial cancer patients have abnormal vaginal bleeding or other discharge. Any abnormal discharge should be checked by a doctor. Pain in the pelvis, a palpable mass (tumor), and unanticipated weight loss can also be symptoms of endometrial cancer.
Most cases of endometrial cancer cannot be prevented, although getting regular exercise and maintaining a healthy diet are always helpful. There are no screening tests or early detection methods for women who are at average endometrial cancer risk and have no symptoms. Routine pelvic exams rarely find this disease. The Pap smear, which is very effective in finding early cancers of the cervix, is not a good screening test for endometrial cancer.
However, regulating hormone balance through the use of oral contraceptives or Intrauterine devices (IUDs), balancing estrogen therapy with Progesterone-like drugs, and having several pregnancies (to take advantage of increased progesterone levels) are helpful to some women. Any hormone therapy can have side effects – some serious – and should be monitored by a doctor. Women with inherited conditions that increase the risk of endometrial cancer can benefit from genetic counseling.
A hysterectomy (removal of the uterus and cervix), often accompanied by removal of the fallopian tubes and ovaries (bilateral salpingo-oophorectomy), is the most typical treatment for endometrial cancer (but is sometimes modified in women who wish to be able to have future pregnancies). Lymph nodes are usually dissected to determine the stage of the cancer. Laparoscopic surgery is being used increasingly for these operations to reduce recovery time. A combination of surgery, radiation therapy, hormonal therapy, and chemotherapy may be used, depending on the type and stage of the cancer and other factors.