Mark Einstein, MD, an associate professor of gynecologic oncology at Montefiore Medical Center, in the Bronx, N.Y., and a spokesman for the Society of Gynecologic Oncology, says the new guidelines are a “data-driven fine-tuning,” not a major overhaul.

“It’s important for patients to realize that the science behind the guidelines is strong,” Dr. Einstein adds.

ACOG’s revisions reflect a trend toward a more conservative approach to managing the cervical abnormalities that sometimes lead to cancer.

Cervical lesions are common, especially among adolescents. About 1 in 5 Pap tests in that age group will turn up an abnormality, but the vast majority of low-grade cervical lesions—up to 90%—will get better on their own within three years. Among older women, the rates are lower, but low-grade lesions still rarely progress to the precancerous stage.

Moreover, a series of studies in recent years suggests that women who have cervical lesions surgically removed or burned away with a laser may be at a higher risk of giving birth to a premature or underweight baby. As a result, ACOG and other organizations now recommend monitoring the condition rather than immediately treating it when some types of lesions are found.

Scaling back the schedule for Pap tests will minimize unnecessary and potentially harmful procedures, the guidelines say. Although they also cite the expense of screening and the anxiety and “emotional impact” caused by abnormal Pap tests, “the risk of treatment was the driving factor” behind the changes, says Dr. Waxman.

ACOG’s recommendations come less than a week after the U.S. Preventive Services Task Force (USPSTF), an independent panel of experts that advises the federal government on preventive care, released new guidelines for breast cancer screening. The USPSTF recommended that women begin mammograms at age 50, not 40, and decrease the frequency thereafter.

Both the mammography and Pap test guidelines are part of a broader, evidence-based shift toward less screening, says Karen Soren, MD, the director of adolescent health services at Columbia University Medical Center, in New York City.

“We always used to feel that the more screens you get, the better. And I think there’s a new philosophy,” says Dr. Soren, who has studied Pap tests in adolescents. “The whole medical community in general is saying, ‘Perhaps we’re overscreening.’ And that relates to mammography as well.”

By changing its guidelines, ACOG is breaking ranks with the other main authorities on cervical cancer. The American Cancer Society (ACS) and the USPSTF both recommend that women get their first Pap test within three years of having sex, or at age 21.

The ACS recommends that women ages 21 to 30 should be tested every one or two years, depending on whether a conventional or liquid-based Pap test is used. Women over 30 with three consecutive normal Pap tests can be screened every two to three years, again depending on which tests are used. (The ACOG guidelines do not distinguish between the different types of testing.)

The USPSTF’s mammogram guidelines, which deviated from those of the ACS, caused an uproar and have sowed confusion among women, but experts agree that the ACOG recommendations aren’t likely to have the same effect.

In fact, the ACOG committee that assembled the guidelines believes it will help eliminate confusion and simplify care. “Now age 21 is there as a landmark point in a young woman’s lifetime: ‘Gee, I’m 21, now it’s time to get my Pap test,’” says Dr. Waxman.

The hope, he says, is that the ACS and the USPSTF will head in the same direction with their own recommendations. “It’s very frustrating when you have three major professional organizations saying three different things,” Dr. Waxman says.

Setting a woman’s first Pap test at age 21 is clearer than pegging it to sexual activity, says Dr. Soren. “The recommendations have been changing and evolving, and people have been slow to catch on,” she says. “Patients have been asking for different things. I think the fact that there are concrete guidelines now is actually better.”

Fred Wyand, a spokesman for the American Social Health Association, a nonprofit organization that raises awareness about HPV and cervical cancer prevention, downplayed the potential for confusion among the public or health-care providers. The debate over the schedule for Pap tests is “not new,” says Wyand. “The guidelines are new, but the discussion that preceded it dates back years. So I don’t think anybody’s going to be caught off guard.”

Experts stress that annual pelvic exams may still be appropriate even though Pap tests will be performed less frequently. And, most importantly, women who have received the HPV vaccine need to stick to the same screening schedule as everyone else.

“It is number one on our list to make sure that patients know that vaccination doesn’t replace screening,” says Dr. Einstein. “We’re not ready to be making separate guidelines for vaccinated and non-vaccinated patients, and we won’t be ready to do so for some time.”