Test for cervical cancer is only as reliable as doctors and labs


June 20, 1995|By Patricia Meisol | Patricia Meisol,Sun Staff Writer

In an isolated section of SmithKline Beecham medical laboratory in Owings Mills, three women pore over microscopes in search of misshapen nuclei. They work in silence, occasionally getting up from the desk to enter their findings in a nearby computer.

Their mission: to locate abnormal cells, the detection of which can save a woman's life.

Their job: one of the toughest in laboratory science.

They are "reading" Pap smears, searching for cancer in cells scraped from a woman's cervix. Imagine trying to find a clump of squares in 20,000 round grains of sand poured on a desk, and you have an idea of what it's like. Now imagine trying to do that 80 times a day.

Since it was invented 40 years ago, the Pap screen has slashed deaths from cervical cancer by 70 percent. It is easy to perform and highly predictive of cancer.

It is also easy to get wrong. Much depends on the quality of the lab -- on the skill of the technicians reading the Pap smears and the conditions under which they work.

But in an era of managed care, labs are under intense pressure to slash prices to win the business of health maintenance organizations. The result is that big labs are taking over, and some worry that the consolidation will undermine quality and affect the accuracy of Pap smears.

Even under the best conditions, Pap smears fail to detect one in five cases of cervical cancer, says Diane Solomon, the chief of cytopathology, the medical specialty of examining cells, at the National Cancer Institute.

There are lots of ways that the test can miss signs of cervical cancer: the abnormal cells are obscured by blood, for instance, or the sample taken by the doctor is blurred. Or the technicians simply don't see it.

"You are looking down at literally thousands and thousands of cells on a smear on a slide. It is very labor intensive," says Howard L. Siegel, president of the Maryland Society of Pathologists and a pathologist at Greater Baltimore Medical Center.

"As humans, we make errors," he says.

4,800 die a year

The possibility for error is the reason women are urged to have the Pap annually -- it improves the chances that the cancer, which develops very slowly, will be caught in its early stages.

Every year, 18,000 women are diagnosed with advanced cervical cancer, and 4,800 women die of the disease, according to the American Cancer Society. Another 300,000 women are successfully treated for abnormalities before those develop into cervical cancer. The Pap test detects these pre-cancerous conditions while they are easily treatable.

"It is enormously effective at what it does -- the fact that it is not infallible should not put someone off," says Dr. Solomon of the National Cancer Institute. "Repeating the smear increases the safety of it."

The test starts at the doctor's office, where cells are scraped from the cervix during a gynecological exam and affixed to a glass slide. At the laboratory, the slide is treated and examined under the microscope for unusual structures or textures by a cytotechnician, a person specially trained to examine cells. Abnormal cells are forwarded to the pathologist, a doctor trained to analyze cells and tissue for disease.

It's tedious work, and it takes someone who doesn't find looking into a microscope all day monotonous. The market for cytotechnologists is extremely competitive and they are well paid -- $50,000 to $60,000 a year is typical.

"It's an extremely technically difficult test to read. It takes a tremendous amount of training and experience," says Dr. Siegel, the GBMC pathologist.

Every morning, doctors in his group meet around a five-view microscope to examine and discuss one Pap smear that someone has found difficult to read. They usually argue, he says.

Setting standards

The likelihood of errors is far greater when a lab takes on more work than it can handle.

In Milwaukee during the late 1980s, technicians at Chem Bio Corp. were reading up to 40,000 slides a year -- twice as many as is safe -- because they were being paid by the number of Pap smears they reviewed.

The lab missed clear signs of cervical cancer in the Pap smears of Delores Geary and Karin Smith, experts testified. Both women later died of cervical cancer. In April, the families of Ms. Geary and Ms. Smith won nearly $6 million in damages from the lab and a health maintenance organization, Family Health Plan.

In Maryland, labs have been restricted in the number of Pap smears they can read since 1988. Technicians can examine no more than 80 to 100 Pap smears in a 24-hour period.

Maryland also pioneered annual tests for cytotechnicians. Regulators bring a known sample of cells to the lab, watch the technician or pathologist read it, and return the sample to state offices. More than 300 technicians and pathologists take the annual proficiency tests.

Maryland's standards were later adopted for the federal law, written largely by Maryland Sen. Barbara Mikulski. The federal law took effect in 1992 and limits all labs to 100 Pap smears per day.

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