PAP TESTS: WHAT YOU NEED TO KNOW
Cancer of the cervix seems like the kind of disease medical science should have wiped out long ago. Linked to viruses, it's detectable and curable in a precancerous stage. When the Pap test was introduced after World War II, the death rate fell 70%. Yet cervical cancer kills almost one of three of the 16,000 women a year in the U.S. who get it. Many people don't understand its nature as a sexually transmitted disease for which almost all women are at risk. Others don't realize that since the late '80s, the venerable Pap test has not been considered a foolproof screening system.
The good news is that researchers are refining their understanding of what puts a woman at risk. At the same time, the Food & Drug Administration has approved several methods that may help eliminate false negatives and inconclusive Pap results. But be prepared to pay--most insurers don't yet cover the costs of the extra tests.
Annual Pap tests should start around age 18, or when a girl first has sex. Most women become infected with the human papilloma viruses (HPVs) linked to cervical cancer through intercourse. Women shouldn't stop getting tested because they're older. Those over 65 account for 4 out of every 10 deaths. Any woman who has had three or more sexual partners or whose current partner has had three or more (among other factors) is considered at risk.
To do a Pap test, a doctor gently scrapes the cervix with a special tool to gather cells. Thousands of cells are then examined under a microscope by a cytotechnologist, who looks for barely visible abnormalities. ''It is one of the most tedious, demanding, individual-attention functions ever invented for the human brain,'' says Leopold Koss, chairman emeritus of pathology at Montefiore Medical Center in the Bronx.
BAD SAMPLE. Experts say about one of five Pap tests is in error, many of them false negatives that show no problem when there actually are abnormal cells (though only a small number lead to cancer). Sometimes the doctor doesn't get a good cell sample. Other times, the technologist fails to detect the abnormal cells. Under federal law, all labs must rescreen for accuracy at least 10% of all of the Pap smears they analyze.
In theory, getting a negative Pap result three years in a row almost guarantees you have no problem. But there is no way to know if your annual Pap test is a false negative, and during that time, there is a small chance you have a rapidly developing invasive cancer. ''The reason to rescreen is that there usually will be a delay of at least a year until a false negative is picked up,'' says Patricia Braly, chief of gynecological oncology at Louisiana State University in New Orleans. Even though few physicians routinely double-check every Pap smear, cancer experts say rescreening can save lives. So women with several risk factors or who just want reassurance might ask their doctor to have the lab look twice. A second manual review will cost about $20.
Two companies with computer-scanning systems say they can help eliminate false negatives and detect signs of cancer earlier. With Auto-Pap, the lab passes slides found to be within normal limits through equipment that identifies the 10% most in need of reevaluation. To use AutoPap, your doctor must send your smear to a lab that offers it. SmithKline Beecham Clinical Laboratories is AutoPap's biggest customer.
To use the Papnet method, labs send ''normal'' slides to Neuromedical Systems' Suffern (N.Y.) facility. Papnet identifies ones needing review. Last month, managed-care provider Magna Care/MagnaHealth said it will provide Papnet rescreening as a covered benefit.
Not everyone gives such rescreening an unqualified endorsement. ''In excellent labs, the abnormality pickup rate could be almost as good as with the automated systems, and at less cost,'' says Cynthia Krause, a gynecologist at the Women's Health Program at Mt. Sinai Medical Center in New York. Also, if your lab doesn't use this technology and your doctor must send the sample elsewhere, you could end up paying for the Pap test and the rescreen.
The Pap test was long due for an update. Hopefully, new technology will put cervical cancer where it belongs--on the list of endangered diseases.
EDITED BY AMY DUNKIN
Updated June 14, 1997 by bwwebmaster
Copyright 1996, Bloomberg L.P.