Cervical Cancer
Cervical Cancer
Why You Need a Pap Smear
Every year you report to the gynecologist for a Pap smear. And every year she props open your vagina, prods your uterus, pokes your ovaries, scrapes a few cells off your cervix and sends them to a lab for analysis.
If you get the lab bill a few weeks later, you know you don't have a problem.
But if you get a phone call from your gynecologist instead, it's a good guess that the Pap smear has signaled cellular changes that may indicate or lead to cervical cancer.
Deaths due to cervical cancer have dropped a whopping 68 percent over the past 30 years, largely because these changes have been detected at such an early stage that radiation or surgery has been able to prevent any cancer from evolving.
"The Pap smear is doing its job," says Vicki Baker, M.D., director of the gynecologic oncology division at the University of Michigan Medical Center in Ann Arbor.
Solid figures are hard to come by. But in 1992 alone, Pap tests signaled abnormal cellular growth in the cervixes of somewhere between 250,000 and 1,000,000 women, according to the American College of Obstetricians and Gynecologists.
How many of those women actually developed cervical cancer is unknown. But based on trends in recent years, the American Cancer Society estimates that in 1992, only 13,500 women would have actually developed invasive cervical cancer.
A Continuum of Change
Cervical cancer does not just pop up unannounced. The cellular changes that characterize its progress may evolve over a 10- to 15-year period.
At one end of the continuum is dysplasia, a condition in which new cervical cells begin to grow in odd shapes and sizes instead of the more symmetrical shapes of healthy cells. They also begin to appear as though they've been plunked down haphazardly rather than lined up in the highly structured rows that are typical of a healthy cervix.
Not all women with dysplastic cells will develop cervical cancer. But because these cellular changes are clearly the first step in that direction, dysplasia is called cervical intraepithelial neoplasia (CIN), a precancerous condition.
If abnormal cell growth continues, the dysplasia will evolve into cancerous cells that line the cervix--in about four years. It is somewhere around this point that symptoms such as bleeding between periods, after douching or after sex may appear.
If the cancer is still not detected and treated, it will grow and become invasive cervical cancer.
Ninety percent of the women who are treated with surgery or radiation while the cancer is confined to the cervix will be alive five years after diagnosis. Sixty-seven percent of the women who are treated for invasive cancer that has spread beyond the cervix into the supporting tissue will also be alive. But only 15 percent of those in whom cancer has spread to the bladder and rectum will survive.
Can You Trust a Pap Test? As far as testing for cervical cancer is concerned, you really don't have any options: The Pap is the only test around that will reveal the health of your cervix. But that doesn't mean it's without faults. Chief among them is a high false-negative rate. Various surveys indicate that around 10 percent of Pap smears are incorrectly read--primarily because reading Pap smears is so boring that lab technicians zone out. Unfortunately, approximately 20 percent of these misreadings incorrectly lead a woman to believe she is healthy when in fact she has signs of cervical cancer. To reduce the error rate as much as possible, the Centers for Disease Control and Prevention in Atlanta require that laboratories rescreen at least 10 percent of all negative cervical smears. And some laboratories mandate that a supervisor rescreen any Pap smear that comes from a woman with any reported gynecological symptoms or abnormalities or even a history of such problems. The result of such meticulous attention to accuracy is an error rate of approximately 5 percent. You can make it easier for technicians to read a Pap smear by making sure the cell sample is as clear as possible, says Vicki Baker, M.D., director of the gynecologic oncology division at the University of Michigan Medical Center in Ann Arbor. Avoid douches and contraceptive creams or jellies for three days prior to the test. Avoid intercourse the night before your test. And schedule a Pap smear before or after your period, not during.
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Putting the Brakes on Cervical Cancer
Perhaps reflecting the long incubation period that most cervical cancer requires, precancerous cell changes are detected in the cervixes of women most often between the ages of 20 and 35, while invasive cancer is detected most often between the ages of 35 and 65.
Exactly how these changes are triggered is still a mystery, but infection with the human papillomavirus, which causes genital warts, or HIV, which causes AIDS, along with such activities as smoking, maintaining a poor diet and having multiple sex partners can put any woman at risk for cervical cancer, says Dr. Baker.
"We have only a sketchy idea of what's happening at the molecular level," she adds. How any of these risk factors actually initiates changes is unknown. Scientists suspect that they either turn on genes that direct the cell to multiply or turn off the cell's tumor suppressor genes, which would normally put the brakes on any uncontrolled growth. Or they may do both.
But even if doctors and researchers aren't sure how these risk factors actually put women in jeopardy, they do have suggestions for how to prevent cervical cancer.
Get a Pap smear. "The single most important thing a woman can do is have an annual Pap smear," says Dr. Baker. "I still see young and middle-aged women who have not had periodic Pap smears." She says she sees these same women having advanced cases of the disease.
Forty percent of all American women have not had a Pap smear within the past three years, reports the American College of Obstetricians and Gynecologists.
The college, the American Cancer Society and the College of Surgeons recommend that a woman have her first Pap smear at age 18 or when she becomes sexually active, whichever comes first, says Dr. Baker. "Following three consecutive, annual negative Pap smears, they can be done at the discretion of the physician."
Depending on whether a woman has human papillomavirus infections or any other conditions that require closer monitoring, most gynecologists like to recommend an annual screening, she adds.
Don't smoke. "Cigarette smoking is an important factor," says Dr. Baker. "It's been recognized for decades that women who smoke are at increased risk for cervical cancer. But only recently has it been recognized that the possible mechanism for this is that the carcinogens in cigarette smoke, by some unknown mechanism, are selectively concentrated in cervical mucus. They're roughly 10- to 15-fold higher than levels found in blood that's measured at the same time." So what you're doing when you smoke is bathing your cervix with cancer-causing chemicals.
Be sexually careful. "Cultivate a mutually monogamous relationship," says Dr. Baker. Studies indicate that the more sexual partners a woman has, the more likely she is to get cervical cancer.
But studies also indicate that the more sexual partners her significant other has, the more likely she is to get cervical cancer. A study of over 300 women in India, for example, found that women whose husbands had other sexual relationships both before and during marriage had nearly seven times the risk of cervical cancer when compared with women whose husbands did not.
Eat right. "Diet may play a role in preventing cervical cancer," says Dr. Baker. "Women who are deficient in folic acid and perhaps vitamin A may be at some increased risk."
A study of more than 450 women at the University of Alabama at Birmingham found that women who did not regularly eat a diet rich in folic acid--and who therefore had little of the vitamin stored in their bodies--were more likely to get cervical dysplasia than women who did.
Researchers couldn't say exactly why, but they pointed out that cells deficient in folic acid were known to be more susceptible to the effects of carcinogens than cells with a rich supply.
In other words, some cancer-causing agents may only trigger cervical cancer if you're deficient in folic acid.
The best sources of folic acid? Cowpeas, beans, lentils, spinach, wheat germ and asparagus. You can also get folic acid by taking a daily multivitamin supplement.
