Category: Diseases and conditions
Anatomy or system affected: Cervix, reproductive system, uterus
Definition
Cervical cancer is a disease in which cancer cells grow in the cervix. The cervix is the lower, narrow part of the uterus that connects the uterus with the vagina. It is the outlet of the uterus through which menses flow and infants are delivered.
Causes
Normally, the cells of the cervix divide in a regulated manner. If cells keep dividing in an unregulated manner, a mass of tissue forms. This mass is called a tumor, and it can be benign or malignant. Squamous cell carcinoma (cancer) can arise either from the squamous cells that line the outer surface of the cervix or, in the case of adenocarcinoma, the glandular cells that are found in the channel that connects to the rest of the womb.
Staging System Used to Classify Cancer of the Cervix
Stage 0: The abnormal cells are found only in the first layer of cells lining the uterus.
Stage I: The cancer involves the cervix but remains in the uterus. This stage has six levels, depending on the size of the cancer: levels IA, IA1, IA2, IB, IB1, and IB2.
Stage II: The cancer has spread to nearby areas but is still inside the pelvic area. This stage has two levels, depending on whether the cancer has spread to the upper two-thirds of the vagina (IIA) or into the pelvis (IIB).
Stage III: The cancer has spread throughout the pelvic area. This stage has two levels, depending on whether the cancer has spread to the lower-third of the vagina (IIIA) or more broadly into the pelvic sidewall (IIIB).
Stage IV: The cancer has spread to other parts of the body. This stage has two levels, depending on what organs the cancer has spread to: level IVA (involving the bladder, rectum, or both) and level IVB, involving more distant organs.
A benign tumor is not cancerous. It will not spread to other parts of the body. A malignant tumor is cancerous, and its cells divide and damage tissue around them. The cells can enter the bloodstream and spread to other parts of the body to become a life-threatening condition.
Pap tests (or smears) are largely responsible for the significant decline in deaths from cervical cancer. Despite this success, more than eleven thousand women in the United States each year are diagnosed with cervical cancer.
Squamous cell carcinoma is more common than adenocarcinoma. Many cases of squamous cancer are associated with a viral infection (such as with the human papillomavirus, or HPV), which, in addition to increasing the risk for cervical cancer, causes tell-tale changes in the cells of the cervix. These changes can be detected by a Pap test and indicate an increased risk for developing cervical cancer. A vaccine has been developed to protect against infection by some (but not all)of the HPV strains associated with cervical cancer.
Risk Factors
It is possible to develop cervical cancer with or without the risk factors of HPV infection, sexual history, history of not having Pap tests, history of diethylstilbestrol (hormone) use by one’s mother, a weakened immune system, and poor nutrition. Other persons at high risk in the United States are African Americans, Hispanics, and American Indians; those without ready access to adequate health care services; smokers; and women age twenty-five years and older. However, the more risk factors, the greater the likelihood of developing cervical cancer.
Risk factors include HPV infection of the cervix. HPV infection is a sexually transmitted disease (STD) and is the primary risk factor for cervical cancer. There are more than seventy types of papillomaviruses. Certain HPV types can cause warts on the female and male genital organs and on the anus. HPV is passed from one person to another during sexual contact. Large studies have found a particular type of HPV (HPV C, with types HPV 16, 18, 31, and 45C) in more than 93 percent of cervical cancer cases. A vaccine has been developed to protect against infection by the most common types of HPV associated with cervical cancer, but the vaccine must be given before infection to be effective.
After age twenty-five years, the risk of developing cervical cancer begins to increase, but this cancer, or its precancerous changes, can be diagnosed in young women in their early twenties and their teenage years. After the age of forty years, the risk of developing cervical cancer remains stable. The risk of dying from cervical cancer increases as women get older.
Women who had sexual intercourse at an early age or women who have had many sexual partners are at an increased risk of cervical cancer. If a woman is with a partner who has had many sexual partners, this also increases her risk.
Women who have never had a Pap test or who have not had one for several years have a higher-than-average risk of developing cervical cancer. This screening tool is quite effective for catching abnormal cell growth early, before it progresses to cancer.
By smoking, a person exposes her or his body to many cancer-causing chemicals. Tobacco by-products have been found in the cervical mucus in women who smoke. The risk appears to increase with the number of cigarettes smoked per day and the number of years a woman has smoked. Smokers are about twice as likely as nonsmokers to get cervical cancer.
Between 1940 and 1971, doctors prescribed diethylstilbestrol (DES), a hormone, to pregnant women who were thought to be at an increased risk for miscarriage. About 1 of every 1,000 women whose mother took DES when pregnant with them will develop cancer of the cervix or vagina. Almost all these women who develop cervical cancer because of DES have an early cellular pattern change in the cervix that can be detected. Women born between 1940 and 1972 who have been exposed to DES, or who are uncertain about their exposure history, should discuss with their doctor how to determine their risk and the best screening measures.
Several reports have shown that women with weakened immune systems, such as those with human immunodeficiency virus (HIV) infection or those taking immune-suppressing drugs after a transplant, are more likely to develop cervical cancer. HIV damages the body’s immune system; this makes a woman more susceptible to HPV infection, which may increase the risk of cervical cancer. In someone with a weakened immune system a cervical precancer may develop into an invasive cancer faster than it normally would in a woman without a weakened immune system.
Poor nutrition is also a factor in the development of cervical cancer. For example, diets low in fruits and vegetables are associated with an increased risk.
In the United States, several racial and ethnicgroups have higher cervical cancer death rates. AmongAfrican Americans, the death rate from cervical cancer is more than twice the national average. Hispanics and American Indians also have death rates above the average.
Also, experts believe that women with low socioeconomic status are at an increased risk because they lack ready access to adequate health care, which may keep women from getting the necessary screening needed to diagnose and treat cervical cancer in its early stages.
Symptoms
There are no obvious signs or symptoms of cervical cancer in its beginning stages. The precancerous changes happening in the cervix usually do not cause pain or other symptoms. Most cervical cancers are detected through a routine pelvic exam and Pap test. Because of this, women should have regular Pap tests.
When the abnormal cells become cancerous, accumulate to a sufficient size, and begin to invade nearby tissues, signs and symptoms may appear. These symptoms include abnormal bleeding, the most common symptom, indicated by bleeding between regular menstrual periods, menstrual bleeding that is heavier or lasts longer than usual, and bleeding after sexual intercourse, douching, a pelvic exam, and menopause. Other symptoms of cervical cancer include increased vaginal discharge and pain during sexual intercourse or in the lower pelvic region.
The foregoing symptoms can be caused by other, less serious conditions, so having these symptoms does not necessarily mean that one has cervical cancer. One should consult a doctor if any of these symptoms occur. Because cervical cancer does not produce symptoms in its earliest and most curable stages, a regular examination by a doctor and regular Pap tests remain the best ways to diagnose this disease in its earliest stages.
Screening and Diagnosis
The number of new cases and deaths caused by cervical cancer is decreasing each year. Experts agree that this is the case because of rising rates of early detection and treatment. Early detection and treatment are possible because of the widespread availability and use of cervical-cancer screening methods, namely the pelvic exam and the Pap test.
The diagnosis of cervical cancer usually begins in a doctor’s office during a routine pelvic exam, which includes a Pap test. The doctor may complete other aspects of a physical exam first, including examining the woman’s thyroid gland, heart, lungs, breasts, and abdomen. Part of the pelvic exam includes an examination of external genitalia for redness and signs of infection. The doctor will next perform a Pap and other tests to check for STDs such as chlamydia or gonorrhea.
The Pap test involves collecting a sample of cells from the outer cervix and its canal. These cells are placed on a slide or suspended in an aqueous solution and sent to a laboratory for evaluation. If the Pap test shows abnormal changes or unhealthy cell growth in the cervix, the doctor will need to perform further testing to determine if the woman has cancer, an infection, or some other condition.
If it is determined that the woman has cervical cancer, additional diagnostic tests are necessary to determine the precise type, location, and extent of the tumor to plan effective treatment. Diagnostic tests will determine the nature of the abnormal cell growth of the cervix. Diagnostic tests include a colposcopy, in which a colposcope (an instrument that shines a light on the cervix and magnifies the view) is used to closely examine the genitals, vagina, and cervix. First, the doctor places the speculum into the vagina and opens it slightly to see the cervix. A vinegar solution is swabbed onto the cervix and vagina. This solution makes abnormal tissue turn white, helping the doctor identify the areas that need to be evaluated. If abnormal cells are found during a colposcopy, the doctor may do a biopsy.
During a biopsy, the doctor removes a small amount of cervical tissue for examination. There are several procedures used to obtain biopsies, including a cone biopsy (also known as cold cone biopsy or cold knife cone biopsy), a procedure that uses a laser or a surgical scalpel to remove tissue; a loop electrosurgical excision procedure (LEEP), which uses an electric wire loop to slice off a thin, round piece of tissue; and an endocervical curettage, which uses a small, spoon-shaped instrument called a curette to scrape tissue from inside the cervical opening.
If the area of abnormal cell growth is small, these biopsy procedures may be able to remove all the affected area. The tissue removed during biopsy is sent to a laboratory to be analyzed. If cancer is found, the patient’s prognosis and treatment depend on the location, size, and stage of the cancer and on the patient’s general health.
Staging is a careful attempt to determine if the cancer has spread and, if it has, what body parts are affected. The higher the stage, the more advanced the cancer and the greater the need for more aggressive therapy. Cure rates decline as the stage of the tumor increases. Additional tests to determine staging may include urine and blood tests; an additional physical exam, including another pelvic exam under anesthesia in surgery; X rays of various parts of the body, including the lungs, bladder, kidneys, and lymph nodes; a barium enema, to check the intestines and rectum with an X ray of the gastrointestinal tract; a CT or CAT scan (a series of X rays that make detailed pictures of areas inside the body); an ultrasonography, in which sound waves are bounced off tissues and the echoes produce a picture; and an MRI, in which a magnet linked to a computer is used to create detailed pictures of areas inside the body.
Treatment and Therapy
The type of treatment for and management of cervical cancer depends on the location and size of the tumor, the stage of the cancer, the patient’s age and general health, and other factors. Cervical cancer treatment most often involves surgery and radiation therapy, and sometimes chemotherapy or biological therapy. Other treatments include lifestyle changes, medications, and alternative and complementary therapies.
Prevention and Outcomes
A risk factor increases one’s chance of developing a disease. Risk factors for many diseases have been identified. Some risk factors, such as smoking, can be avoided. Other risk factors, such as genetic predisposition, are out of a person’s control. Having a certain risk factor does not mean that a person will definitely get a certain disease, but if it is a controllable risk factor, and the person changes it, the risk can be reduced. This is true for cervical cancer too. Several risk factors can be modified by having Pap tests, by practicing safer sex, by considering vaccination, by avoiding smoking, and by eating a balanced diet.
Pap tests. Early detection and treatment of precancerous tissue remain the most effective ways of preventing cervical cancer. Because cervical cancer rarely produces symptoms in its early stages, the best way to detect it is to have pelvic exams and Pap tests. In November, 2009, the American Congress of Obstetricians and Gynecologists updated its guidelines for Pap tests. These guidelines recommend that women age twenty-one to twenty-nine years have a Pap test every two years and women age thirty years or older, every three years. Women age sixty-five years and older may be able to stop having the Pap tests done if they have had normal results for the previous three Pap tests and have had no abnormal results for the previous ten years. However, regular, more frequent Pap tests are recommended for all women who have had abnormal results or have certain conditions, such as a suppressed immune system or a history of cervical dysplasia or cervical cancer.
Safer sex. Infection with the human papillomavirus (HPV), an STD, is the primary risk factor for cervical cancer. Women who have had multiple sex partners or who began having sex before the age of sixteen years are at greater risk of exposure to HPV infection and of developing cervical cancer.
To decrease the risk of getting an STD or cervical cancer, one should maintain a monogamous relationship. However, if a woman is not in a monogamous relationship, she should insist on the use of a condom during sexual intercourse. Although it is always wise to use a condom to prevent some STDs, a condom will not prevent an HPV infection because the virus can be transmitted by perianal contact.
Vaccination. Two vaccines, Gardasil and Cervarix, have been approved to prevent infection by some, but not all, HPV strains that cause cervical cancer. The vaccines reduce the risk of infection from two HPV strains (16 and 18) that account for more than 70 percent of HPV infections that lead to cancer. Gardasil also protects against two additional HPV strains that cause genital warts.
For both vaccines, three injections are required in a period of six months. It is not known how frequently boosters will be required or the degree to which the vaccine will be effective in the long term because of changes in antibody titers through time. In addition, the vaccines ideally should be given before sexual activity begins, as vaccination after exposure to the strains of HPV in the vaccine is ineffective. Gardasil is approved for use in females and males nine to twenty-six years of age, and Cervarix is approved for use in females ten to twenty-five years of age.
Smoking. Smoking exposes the body to many cancer-causing chemicals. Smokers are about twice as likely as nonsmokers to develop cervical cancer, so stopping will greatly reduce the risk of cervical cancer.
Balanced diet. Good nutrition is essential for health and well being. Women with poor diets may be at an increased risk for cervical cancer. Studies have found an association between diets low in fruits and vegetables and an increased risk of cervical cancer.
Further Reading
American Congress of Obstetricians and Gynecologists. “First Cervical Cancer Screening Delayed Until Age Twenty-one: Less Frequent Pap Tests Recommended.” Available at http://www.acog.org.
Berek, Jonathan S., ed. Berek and Novak’s Gynecology. 14th ed. Philadelphia: Lippincott Williams & Wilkins, 2007.
Dollinger, Malin, et al. Everyone’s Guide to Cancer Therapy. 5th ed. Kansas City, Mo.: Andrews McMeel, 2008.
Dunne, E. F., and L. E. Markowitz. “Genital Human Papillomavirus Infection.” Clinical Infectious Diseases 43 (2006): 624.
Henderson, Gregory, and Batya Swift Yasgur. Women at Risk: The HPV Epidemic and Your Cervical Health. New York: Putnam, 2002.
Hoskins, William J., et al., eds. Principles and Practice of Gynecologic Oncology. 4th ed. Philadelphia: Lippincott Williams & Wilkins, 2005.
Kerr, Shelly K., and Robin M. Mathy. Preventive Health Measures for Lesbian and Bisexual Women. New York: Haworth Medical Press, 2006.
“Quadrivalent Vaccine Against Human Papillomavirus to Prevent High-Grade Cervical Lesions.” New England Journal of Medicine 356 (2007): 1915-1927.
Rushing, Lynda, and Nancy Joste. Abnormal Pap Smears: What Every Woman Needs to Know. Rev. ed. Amherst, N.Y.: Prometheus Books, 2008.
Sarg, Michael J., and Ann D. Gross. The Cancer Dictionary. 3d ed. New York: Checkmark Books, 2007.
Schottenfeld, David, and Joseph F. Fraumeni, Jr., eds. Cancer Epidemiology and Prevention. 3d ed. New York: Oxford University Press, 2006.
Weinberg, Robert. The Biology of Cancer. New York: Garland Science, 2007.