What is vaginal cancer?
Related conditions: Cancers of the vulva, cervical cancer, uterine cancers, ovarian cancers, colon cancer, and rectal cancer.
Definition: The vagina is a muscular, tubelike structure that extends from the vulva, or the visible external genitalia, to the uterus. Cancer of the vagina involves a tumor that arises within the vagina rather than as an extension, metastasis, or recurrence from the cervix or vulva.
Risk factors: Risk factors for vaginal cancer include age over sixty years, human papillomavirus (HPV) infection, exposure to diethylstilbestrol (DES, banned in the United States in 1971) in utero, a history of cervical cancer, vaginal adenosis, uterine prolapse, cigarette smoking, chronic vaginal irritation, low socioeconomic status, hysterectomy at an early age, and vaginal trauma.
Etiology and the disease process: Precancerous changes involving the vagina are much less common than precancerous changes affecting the cervix or vulva. Although not proven, it is thought that the lack of glands in the vagina is the basis for the rarity. Most vaginal cancers are metastatic, originating from cancers of the cervix or vulva with spread to the vagina, although metastases have been reported to occur from the uterus, ovaries, colon, rectum, breast, and even the kidney. Metastasis to the vagina occurs by spread from the lymphatics or blood.
Incidence: There are approximately 2,420 new cases of vaginal cancer in the United States each year. The estimated incidence of vaginal cancer is 0.42 case per 100,000 women. Vaginal cancer accounts for 1 to 3 percent of malignancies involving the female reproductive tract. Over 90 percent of vaginal cancers are classified as squamous cell carcinomas.
Symptoms: The most common symptoms associated with cancers of the vagina are abnormal bleeding or an excessive, nonodorous, watery discharge; less frequent symptoms include pelvic pain, an increased frequency of urination or pain with urination, pain during sexual intercourse, and constipation. Occasionally a lump or mass may be felt in the vagina.
Screening and diagnosis: Screening for vaginal cancer should be performed in the context of a woman’s annual physical examination, sometimes called a well-woman examination. During the examination, the gynecologist inspects the vaginal walls for lesions, areas of discoloration, or abnormal discharge. Proper inspection of the vagina requires rotation of the speculum during the examination so that all areas of the vaginal wall are visualized, with continued inspection during removal of the speculum.
A diagnosis of vaginal cancer is made, based on a tissue biopsy, Pap test, or colposcopy, after an abnormality is seen on physical examination. Because symptoms of vaginal cancer are often absent or nonspecific, its diagnosis is often missed or delayed. Although useful in determining the extent of disease, computed tomography (CT) and magnetic resonance imaging (MRI) are not used to make the initial diagnosis of cancer of the vagina.
The most common types of vaginal cancer are squamous cell carcinoma, adenocarcinoma, and melanoma. Squamous cell carcinomas usually occur high in the vagina and have the appearance of ulcerating masses that look like large warts or fleshy lesions.
Adenocarcinomas of the vagina have peak occurrences in women over fifty years old, but the subtype clear cell adenocarcinoma occurs in younger women with known exposure to DES as a fetus (in utero exposure) due to maternal use of the drug. It is known that DES exposure does not affect all such women; in fact, only one in one thousand women exposed to DES in utero will develop clear cell adenocarcinoma. Nevertheless, women so exposed should undergo more frequent screening at the discretion of the physician and patient. It is generally recommended that women with exposure to DES as a fetus should undergo their initial gynecologic examination at the time of menarche (onset of menstrual activity) and have increased lifelong surveillance at the discretion of their physician. Vaginal melanomas are rare and usually affect women older than sixty.
Cancer of the vagina is staged according to the International Federation of Gynecology and Obstetrics (FIGO).
- Stage 0: Carcinoma in situ; the cancer is localized without apparent spread.
- Stage I: Cancer is limited to the vaginal wall.
- Stage II: Cancer has extended to the subvaginal tissues but not to the pelvic wall.
- Stage III: Cancer involves the pelvic wall.
- Stage IV: Cancer has spread beyond the pelvis or has extended to the bladder or rectum.
Treatment and therapy: Although both surgery and radiation therapy have been used to treat squamous cell carcinomas of the vagina depending on the cancer's stage, radiation therapy is most common. Initially, external radiation is used to shrink the tumor mass; this is followed by internal radiation therapy to maximize the toxic effect. Surgical treatment of squamous cell carcinoma can range from local procedures (such as destruction of lesions with laser treatment or surgical excision of the lesions) to more radical procedures (such as removal of part or all of the vagina (vaginectomy); hysterectomy; pelvic exenteration; and hysterectomy with removal of the bladder, bowel, or both).
Because most patients with clear cell adenocarcinoma are young, removal of the uterus (hysterectomy) and partial or complete vaginectomy, followed by creation of a new vagina (neovagina) with skin grafts, is the standard treatment.
Vaginal melanomas are best treated with complete excision and dissection of the lymph nodes. Because of the depth of invasion, vaginal melanomas do not respond well to radiation or chemotherapy, and the goal is complete excision with clear surgical margins (in other words, the excised specimen has a central tumor with normal tissue completely surrounding the tumor).
Prognosis, prevention, and outcomes: The prognosis for vaginal cancer is directly related to the stage at the time of diagnosis as well as the type. The overall relative five-year survival rate is near 50 percent. The five-year survival rates for squamous cell carcinoma of the vagina range from over 70 percent for Stage I to around 50 percent for more advanced tumors. The larger the area of the vagina affected the worse the prognosis becomes. The average five-year survival rate for adenocarcinoma of the vagina is about 60 percent. Vaginal melanomas frequently recur, and the five-year survival rate is about 13 percent.
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