Cervical cancer

Each year, 15,000 women in the United States develop cancer of the cervix.  African American women are twice as likely to die from this cancer as the national average.  Hispanics and American Indians also have higher rates than the national average.  Although cervical cancer can affect young women, the average age of women who develop cervical cancer is between 50 and 55 years.  It is important for older women to continue to have Pap tests.

The cervix is the lower, narrow part of the uterus (womb). The cervix forms a canal that opens into the vagina, which leads to the outside of the body.

Cancer of the cervix also may be called cervical cancer. Like most cancers, it is named for the part of the body in which it begins.  Cancers of the cervix also are named for the type of cell in which they begin. Most cervical cancers are squamous cell carcinomas.  Squamous cells are thin, flat cells that form the surface of the cervix.  (NOTE: Cancer of the cervix is different from cancer that begins in other parts of the uterus and requires different treatment. The most common type of cancer of the uterus begins in the endometrium, the lining of the organ.)

Precancerous Conditions and Cancer of the Cervix

Cells on the surface of the cervix sometimes appear abnormal but not cancerous. Scientists believe that some abnormal changes in cells on the cervix are the first step in a series of slow changes that can lead to cancer years later. That is, some abnormal changes are precancerous; they may become cancerous with time.

One term now used to refer to abnormal changes in the cells on the surface of the cervix is squamous intraepithelial lesion (SIL). (The word lesion refers to an area of abnormal tissue; intraepithelial means that the abnormal cells are present only in the surface layer of cells.) Changes in these cells can be divided into two categories.  Low-grade SIL refers to early changes in the size, shape, and number of cells that form the surface of the cervix. Some low-grade lesions go away on their own. However, with time, others may grow larger or become more abnormal, forming a high-grade lesion.  High-grade SIL means there are a large number of precancerous cells; they look very different from normal cells. Like low-grade SIL, these precancerous changes involve only cells on the surface of the cervix.

If abnormal cells spread deeper into the cervix or to other tissues or organs, the disease is then called cervical cancer, or invasive cervical cancer. It occurs most often in women over the age of 40.

Early Detection

If all women had pelvic exams and Pap tests regularly, most precancerous conditions would be detected and treated before cancer develops. That way, most invasive cancers could be prevented. Any invasive cancer that does occur would likely be found at an early, curable stage.

In a pelvic exam, the doctor checks the uterus, vagina, ovaries, fallopian tubes, bladder, and rectum for any abnormality in their shape or size.

The Pap test is a simple, painless test to detect abnormal cells in and around the cervix. A woman should have this test when she is not menstruating; the best time is between 10 and 20 days after the first day of her menstrual period. For about 2 days before a Pap test, she should avoid douching or using spermicidal foams, creams, or jellies or vaginal medicines (except as directed by a physician), which may wash away or hide any abnormal cells.

Women should have regular checkups, including a pelvic exam and a Pap test, if they are age 18 or older, or earlier if they are sexually active.

Symptoms

Precancerous changes of the cervix usually do not cause pain. In fact, they generally do not cause any symptoms and are not detected unless a woman has a pelvic exam and a Pap test.

Symptoms usually do not appear until abnormal cervical cells become cancerous and invade nearby tissue. When this happens, the most common symptom is abnormal bleeding. Bleeding may start and stop between regular menstrual periods, or it may occur after sexual intercourse, douching, or a pelvic exam. Menstrual bleeding may last longer and be heavier than usual. Bleeding after menopause also may be a symptom of cervical cancer. Increased vaginal discharge is another symptom of cervical cancer.  These symptoms may be caused by cancer or by other health problems. Only a doctor can tell for sure. It is important for a woman to see her doctor if she is having any of these symptoms.

Cause and Prevention

Several factors have been shown to increase the risk of cervical cancer.  However, many women with these “risk factors” will not develop cancer.  Having a risk factor should be a signal to have regular Pap tests.

Research has shown that women who began having sexual intercourse before age 18 and women who have had many sexual partners have an increased risk of developing cervical cancer. Women also are at increased risk if their partners began having sexual intercourse at a young age, have had many sexual partners, or were previously married to women who had cervical cancer.

Scientists do not know exactly why the sexual practices of women and their partners affect the risk of developing cervical cancer.  However, research suggests that some sexually transmitted viruses can cause cells in the cervix to begin the series of changes that can lead to cancer.  Scientists are studying the effects of sexually transmitted human papillomaviruses (HPVs). Some sexually transmitted HPVs cause genital warts (condylomata acuminata). In addition, scientists believe that some of these viruses may cause the growth of abnormal cells in the cervix and may play a role in cancer development. They have found that women who have HPV or whose partners have HPV have a higher-than-average risk of developing cervical cancer. However, most women who are infected with HPV do not develop cervical cancer, and the virus is not present in all women who have this disease. For these reasons, scientists believe that other factors act together with HPVs. For example, the genital herpes virus also may play a role.

Smoking also increases the risk of cancer of the cervix, although it is not clear exactly how or why. The risk appears to increase with the number of cigarettes a woman smokes each day and with the number of years she has smoked.

Some researchers believe that there is an increased risk of cervical cancer in women who use oral contraceptives (the pill).  However, scientists have not found that the pill directly causes cancer of the cervix. This relationship is hard to prove because the two main risk factors for cervical cancer--intercourse at an early age and multiple sex partners--may be more common among women who use the pill than among those who do not. Still, oral contraceptive labels warn of this possible risk and advise women who use them to have yearly Pap tests.

At present, early detection and treatment of precancerous tissue remain the most effective ways of preventing cervical cancer.

However, risk can be markedly reduced with a diet high in fruit and vegetables.