Cancer of the Cervix
The cervix is the lower part of the uterus. It extends into the vagina. Of gynecologic cancers, cervical cancer (cervical carcinoma) is the third most common among all women and the most common among younger women. It usually affects women aged 35 to 55, but it can affect women as young as 20.
This cancer is caused by the human papillomavirus which is transmitted during sexual intercourse. This virus also causes genital warts (see Section 17, Chapter 200). The younger a woman was the first time she had sexual intercourse and the more sex partners she has had, the higher her risk of cervical cancer.
About 85% of cervical cancers are squamous cell carcinomas, which develop in the scaly, flat, skinlike cells covering the cervix. Most other cervical cancers are adenocarcinomas, which develop from gland cells, or adenosquamous carcinomas, which develop from a combination of cell types.
Cervical cancer begins on the surface of the cervix and can penetrate deep beneath the surface. The cancer can spread directly to nearby tissues, including the vagina. Or it can enter the rich network of small blood and lymphatic vessels inside the cervix, then spread to other parts of the body.
Symptoms and Diagnosis
In the early stages, cervical cancer usually causes no symptoms. It may cause spotting or heavier bleeding between periods, bleeding after intercourse, or unusually heavy periods. In later stages, such abnormal bleeding is common. Other symptoms may include a foul-smelling discharge from the vagina, pain in the pelvic area or lower back, and swelling of the legs. The urinary tract may be blocked; without treatment, kidney failure and death can result.
Routine Papanicolaou (Pap) tests or other similar tests can detect the beginnings of cervical cancer (see Section 22, Chapter 242). Cervical cancer begins with slow, progressive changes in normal cells on the surface of the cervix. These changes are called dysplasia. Untreated, these cells may become cancerous with time, sometimes after years. When performing a Pap test, doctors look for these changes as well as for cancer. Women with dysplasia should be checked again in 3 to 4 months.
A Pap test can accurately and inexpensively detect up to 90% of cervical cancers, even before symptoms develop. Consequently, the number of deaths due to cervical cancer has been reduced by more than 50% since Pap tests were introduced. Doctors often recommend that women have their first Pap test when they become sexually active or reach the age of 18 and that a Pap test be performed annually. If test results are normal for 3 consecutive years, women may schedule Pap tests every 2 or 3 years as long as they do not change their sexual lifestyle. Any woman who has had cervical cancer or dysplasia should continue to have Pap tests at least annually. If all women had Pap tests on a regular basis, deaths from this cancer could be virtually eliminated. However, about 50% of American women are not tested regularly.
If a growth, a sore, or another abnormal area is seen on the cervix during a pelvic examination or if a Pap test detects an abnormality or cancer, a biopsy is performed. Usually, doctors use an instrument with a binocular magnifying lens (colposcope) to examine the cervix and to choose the best biopsy site. Two different types of biopsy are performed. In a punch biopsy, a tiny piece of the cervix, selected using the colposcope, is removed. In endocervical curettage, tissue that cannot be viewed is scraped from inside the cervix. These biopsies cause little pain and a small amount of bleeding. The two together usually provide enough tissue for pathologists to make a diagnosis.
If the diagnosis is not clear, doctors perform a cone biopsy to remove a larger cone-shaped piece of tissue. Usually, a thin wire loop with an electrical current running through it is used. This procedure is called the loop electrosurgical excision procedure (LEEP). Alternatively, a laser (using a highly focused beam of light) can be used. Either procedure requires only a local anesthetic and can be performed in the doctor's office. A cold (nonelectric) knife is sometimes used, but this procedure requires an operating room and an anesthetic.
If cervical cancer is diagnosed, its exact size and locations (its stage) are determined. Staging begins with a physical examination of the pelvis and various procedures (such as cystoscopy, a chest x-ray, intravenous urography, and sigmoidoscopy) to determine whether the cancer has spread to nearby tissues or to distant parts of the body. Other procedures, such as computed tomography (CT), magnetic resonance imaging (MRI), a barium enema, and bone and liver scans, may be performed.
Prognosis and Treatment
Prognosis depends on the stage of the cancer (see Section 22, Chapter 252). With treatment, 80 to 90% of women with stage I cancer and 50 to 65% of those with stage II cancer are alive 5 years after diagnosis. Only 25 to 35% of women with stage III cancer and 15% or fewer of those with stage IV cancer are alive after 5 years.
Treatment also depends on the stage. If only the surface of the cervix is involved, doctors can often completely remove the cancer by removing part of the cervix using the loop electrosurgical excision procedure, a laser, or a cold knife. Or cryotherapy may be used to destroy the cancer by freezing it. These treatments preserve a woman's ability to have children. Because cancer can recur, doctors advise women to return for examinations and Pap tests every 3 months for the first year and every 6 months after that. Rarely, removal of the uterus (hysterectomy) is necessary.
If the cancer has begun to spread within the pelvic area, hysterectomy plus removal of surrounding tissues, ligaments, and lymph nodes (radical hysterectomy) is necessary. The ovaries may be removed. Normal, functioning ovaries in younger women are not removed. Alternatively, radiation therapy may be used. It usually causes few or no immediate side effects, but it may irritate the bladder or rectum. Later, as a result, the intestine may become blocked, and the bladder and rectum may be damaged. Also, the ovaries usually stop functioning. With either radical hysterectomy or radiation therapy, about 85 to 90% of women are cured.
If the cancer has spread further within the pelvis or to other organs, radiation therapy is preferred. This treatment is ineffective in about 40% of women with large or extensive cancers.
When the cancer has spread extensively or recurs, chemotherapy, usually with cisplatin and ifosfamide, is sometimes recommended. However, chemotherapy reduces the cancer's size and controls its spread in only 25 to 30% of women treated, and this effect is usually temporary.
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