Pap Tests Often Given When Not Needed

Dec. 3, 2012 -- Against clinical guidelines, many women are still getting Pap smears (a test that’s meant to find cancer of the cervix) even after they've had a total hysterectomy, which removes the uterus and cervix, according to a new government report.

The cervix is the “neck-like” lower part of the uterus. A Pap test uses cells scraped from the cervix to check for early changes that may indicate cervical cancer or precancer. The new report, from the CDC, looked at trends in Pap testing in U.S. women from 2000 to 2010.

In telephone surveys of thousands of women, about 60% of those over age 30 who said they’d had a hysterectomy also reported having a recent Pap smear in 2010.

Even though that number was down about 15 percentage points since 2000, researchers said it was still too high.

“Some of these women would need continued screening, for various reasons, but that’s a small percentage,” says researcher Meg Watson, MPH, an epidemiologist with the CDC’s Division of Cancer Prevention and Control. “We wouldn’t think it would be 60%.”

A hysterectomy is an operation that removes all or part of the uterus. The most common kind of hysterectomy is a total hysterectomy, or an operation that removes both uterus and cervix.

Even after the cervix has been removed, doctors can scrape cells from an area called the vaginal cuff. And in the past, Watson says, many doctors continued to perform the test even after a total hysterectomy to check for signs of vaginal cancers.

“But vaginal cancer rates are quite low,” Watson says, and subsequent studies have shown that using Pap smears to find vaginal cancers isn’t an effective strategy.

Experts who were not involved in the research agree.

“It doesn’t really make a lot of sense,” says Virginia Moyer, MD, MPH, a pediatrician and chair of the U.S. Preventive Services Task Force, a panel of expert advisors that makes recommendations about tests and treatments that are meant to prevent disease.

Last year, the panel said most healthy women only need Pap smears every three years, and it advised women who’d had total hysterectomies for reasons other than cancer to skip the test altogether.

The American College of Obstetricians and Gynecologists and the American Cancer Society also recommended against routine Pap smears after a total hysterectomy.

“The only thing I can sort of speculate is that people get in the habit of doing them and just keep doing them without really thinking about it, which is regrettable,” Moyer says.

The Pap test is one of the great success stories in medicine. Before it was introduced, in the 1950s, cervical cancer was a leading cause of cancer death in women. The test is credited with helping cut the rates of cervical cancer deaths by 60% between 1955 and 1992.

But like many cancer screening tests, Pap tests can be harmful as well as helpful.  

Watson says studies have shown that for every 100 abnormal Pap tests, only one woman will actually turn out to have cervical cancer. But all 100 women would need additional testing and sometimes invasive procedures to rule out cancer. That can cause significant anxiety and stress.

In cases where a woman has her cervix or uterus removed after cervical cancer, she would need to continue to get a regular Pap smear to check for cancer recurrence, Watson says.

But about 90% of hysterectomies are performed for non-cancerous conditions, like uterine fibroids.

“Obviously the large majority of that group would be people who had an unnecessary Pap smear,” Moyer says.

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