Departments
Health Matters
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Week of 25 September 1998 |
Vol. II, No. 7 |
Health Matters
Pap test: An ally in the fight against cervical cancer
I have read about a new Pap smear test that is available. How is the test different, and is it effective?
What you have read is not exactly true. There is no new Pap test available on the market today. What is available, however, is a new procedure for collecting and processing Pap test specimens.
"There is nothing different from a woman's perspective about this new procedure," says Valena Soto-Wright, M.D., director of gynecologic oncology at Boston Medical Center and an assistant professor of obstetrics and gynecology at Boston University School of Medicine. "This is simply a different way of processing the specimen taken during a Pap test. It's the exact same exam for women."
With the new collection method, which was approved by the FDA in 1996, cells scraped from the cervix are rinsed in a vial filled with a solution that preserves them, rather than smeared onto a slide. The vial is sent to a lab that has an automated instrument designed to separate the cervical cells from obstructions, such as inflammation, blood and mucus. "The advantage of this new collection method," says Soto-Wright, "is that the number of false negative readings [normal readings that should have been read as abnormal] are likely to decrease because specimens will be more readable. This will reduce the need for repeat testing. It won't have any effect at all on positive readings." About 10 percent of all Pap tests show false negative readings.
In 1943, George Papanicolaou, M.D., introduced his Pap smear as a cervical cancer screening test, and today the Pap test is capable of detecting nearly 90 percent of both precancerous and cancerous conditions of the cervix. Since the test's introduction, the annual number of deaths from cervical cancer has dropped from 35,000 in the 1940s to fewer than 5,000 today.
Cervical cancer, a slow-growing disease, is believed to be caused by certain strains of the human papillomavirus. Women who are sexually active are at risk for cervical cancer. Cigarette smoking, multiple sexual partners, and immune deficiencies such as AIDS also play a part in the disease. Because symptoms don't present themselves until the disease has become serious, the Pap test is a woman's best defense against the disease. Early detection of the cervical cancer through the Pap test is the key to saving many women's lives.
"The biggest risk factor in cervical cancer is never having a Pap test," says Soto-Wright. "About 90 percent of all cervical cancer cases can be prevented by having this test. I can't stress how important it is."
The Pap test, however, is not 100 percent accurate and, says Soto-Wright, is not a diagnostic tool, but rather a screening device. Because of sampling errors, some Pap tests may still be misread. The new collection and processing procedure may help to reduce the number of false negatives.
Abnormal Pap test readings do not necessarily mean the presence of pre-cancerous or cancerous cells. Infection, inflammation, atrophy, and age-related changes from a lack of estrogen in postmenopausal women may also cause an abnormal reading and need to be ruled out before a woman is diagnosed with a precancerous or cancerous condition.
If a Pap test is positive, Soto-Wright says the standard practice is colposcopy (viewing the cervix magnified through an instrument similar to a microscope) followed by a biopsy of the tissue removed during the test to confirm the presence of cancerous cells. If cancerous cells are detected, a treatment plan will be developed by the patient's physician.
The American College of Obstetrics and Gynecology recommends that all women have annual Pap tests when they become sexually active or once they are 18 years old. Pregnant women should have a Pap test as part of their routine prenatal testing and then again at the six-week postpartum exam.
"Health Matters" is written in cooperation with staff members of Boston Medical Center. For more information on cervical cancer or other health matters, call 638-6767.