Among the three most common gynecologic cancers of the female reproductive system, uterine cancer is the most common in the United States. Approximately 37,000 women will be diagnosed with uterine cancer each year. Fortunately, the overall cure rate for uterine cancer is high with greater than 80% of women developing uterine cancer being cured. The uterus, situated in the female pelvis, is comprised of a muscular wall surrounding the uterine cavity, which is also known as the endometrial cavity. Cancers of the uterus can arise from either the lining of the uterine cavity or from the muscular wall of the uterus. Uterine cancers arising from the lining of the cavity, termed the endometrium, are commonly referred to as endometrial cancers. Uterine cancers arising from the muscular wall are referred to as uterine sarcomas. Because over 95% of uterine cancers are endometrial cancers, these terms are often used synonymously. Since the great majority of uterine cancers are endometrial cancers, most of the discussion in this section will focus on endometrial cancers, although in general, uterine sarcomas are managed similarly to endometrial cancers.
Although younger women may develop uterine cancers, as in many other cancers, uterine cancer tends to arise in older women with an average of diagnosis at approximately 60 years of age. One important risk factor in developing uterine cancer is increased estrogen hormone exposure. Estrogens are a class of female hormones that are a potent growth stimulator of the endometrium. Estrogens are sometimes administered as hormone replacement therapy to treat conditions associated with perimenopause and menopause. When administered alone for hormone replacement therapy, estrogen increases a woman’s risk of developing endometrial cancer. The progestins, another class of female hormones, counteract the proliferative effects of estrogen on the endometrium and are therefore often given along with estrogens in women on hormone replacement therapy for the main purpose of reducing the increased risk of developing endometrial cancer due to estrogen.
Several other risk factors for developing endome-trial cancer are related to the principle of increased estrogen exposure. One such risk factor is obesity. This is because one area of production of estrogens other than the ovary is in adipose tissue or fat cells. Women who are obese, therefore, have higher endogenous production of estrogens. Women who have had a history of using oral contraceptives (birth control pills) have a reduced lifetime risk of developing uterine cancers.
Most women who have uterine cancers will have symptoms of some type of abnormal vaginal bleeding. This can range from minimal vaginal spotting or a bloody vaginal discharge to heavy bleeding in between periods or during periods. Any woman with irregular vaginal bleeding, and especially menopausal women who have any type of vaginal bleeding should see a physician for further evaluation. A physician will then decide, based on history and examination, whether such symptoms need to be further evaluated for cancer. As part of the evaluation, additional tests may include an endometrial biopsy, uterine dilation and curettage, hysteroscopy, or a pelvic ultrasound.
An endometrial biopsy is commonly done in the office in which a small narrow tube (thinner than a pencil) made of either plastic or metal is inserted through the entrance of the cervix (the lower portion of the uterus that extends into the vagina) into the uterine cavity followed by aspiration of a small amount of tissue from the uterine cavity. This procedure can cause cramping and pain very briefly. Most women are able to tolerate this office procedure very well. Potential problems associated with this procedure include an inability to successfully insert the biopsy tube into the uterine cavity due to a cervical stenosis (excessive narrowing of the opening of the cervix). Other problems that may occur from endometrial biopsies but are rare may include infection or uterine perforation (creating a hole in the uterus).
A dilation and curettage (commonly referred to as D&C) is another method a physician may select to evaluate for the possibility of uterine cancer. This is a procedure usually performed in the operating room under anesthesia in which the entrance to the cervix is opened (dilated) followed by a scraping (curettage) of the
uterine cavity. Both the endometrial biopsy and D&C provide tissue from the endometrial cavity for submission to the pathologist (a physician who examines the tissue under a microscope to determine whether there is cancer). Risks of a D&C include the same as for an endome-trial biopsy; however, because the D&C is a more invasive procedure, there are additional risks including the risk of anesthesia. Despite being a more invasive procedure, a physician may select a D&C over an endome-trial biopsy for several reasons including the following:
- Women may not be able to tolerate an endometrial biopsy in the office.
- A significant narrowing of the entrance of the cervix may prevent successful sampling of the endometrial cavity.
- Women who have heavy uterine bleeding may require a D&C as not only a diagnostic procedure, but also as a therapeutic procedure to stop the heavy bleeding.
- There may be situations in which a physician may need a greater sampling of tissue and a D&C may be able to provide this better than an endometrial biopsy.
At the time of the endometrial biopsy or D&C, a hysteroscopy may also be performed as part of the evaluation. Hysteroscopy is a procedure in which a “telescope” is inserted into the uterine cavity allowing direct visualization of the cavity. In addition to these tests that are available, a physician may also select pelvic ultrasound to evaluate uterine bleeding. Pelvic ultrasonog-raphy is a radiologic evaluation in which sound waves are used to visualize the pelvic organs including the uterus. Current technology allows visualization of the thickness of the endometrial cavity, which is almost always thickened in endometrial cancers. However, many other noncancerous conditions may cause an increased thickness in the endometrial cavity.
TREATMENT AND PROGNOSIS
The primary treatment of uterine cancer is surgery. The surgery that is performed includes a hysterectomy (removal of the uterus) and bilateral salpingo-oophorectomy (removal of the attached ovaries and fallopian tubes). In addition, other biopsies including removal of lymph nodes in the pelvis and in the abdomen may be performed during surgery to determine if there is spread of the cancer. Radiation therapy may be offered as an alternative to surgery in women who are unable or unwilling to have surgery. Nevertheless, surgery is the preferred method of treatment as it results in a higher cure rate when compared with radiation therapy. Cure rates for surgery have been reported to be between 80% and 94% compared with 60% and 80% for radiation therapy.
After surgery, the woman may, however, be offered radiation therapy as adjuvant therapy. This is sometimes done for women with spread of uterine cancer to the lymph nodes or who have other high-risk features portending a higher risk for cancer recurrence. Rarely, for young women who wish to maintain the ability to get pregnant, hormonal therapy with progestins may be a consideration, but only if the cancer is considered a very early cancer.
During the consultation regarding endometrial cancer, a physician may use terms such as stage and grade to characterize the cancer. The stage of a cancer ranging from Stage I to Stage IV refers to the extent of spread of the cancer with Stage I being a cancer confined to the uterus and Stage IV indicating spread beyond lymph nodes and uterus, usually advanced spread. The grade of the cancer refers to the degree of differentiation of the cancer cells or how aggressive the cancer cells appear under the microscope. Pathologists currently grade endometrial cancers from 1 to 3 with grade 1 indicating a well-differentiated or not so aggressive appearing cancer, a grade 3 indicating a poorly differentiated or aggressive-appearing cancer, and a grade 2 in between. Important prognostic factors of endometrial cancer, meaning factors that indicate how well the cancer will respond to treatment, include the stage, grade, and status of lymph node involvement. Fortunately, uterine cancer has a high cure rate because most women with uterine cancer are diagnosed at an early stage, confined to the uterus. The overall cure rate of uterine cancer is greater than 80%. For the majority of women who are diagnosed with cancer confined to the uterus, the cure rate is greater than 90%.