Changes in the cervical cancer screening guidelines, as recommended by the U.S. Preventive Services Task Force (USPSTF), mainly concern longer intervals between screening tests and recommended ages when women should start and stop being screened. USPSTF Co-Vice Chair Michael L. LeFevre, MD, MSPH, addressed some of the questions that patients might have about the revised guidelines.

Do the cervical cancer screening guidelines apply to all women?

No. In general, the guidelines apply to women who have a cervix, regardless of sexual history, and are aged 21 to 65, although as noted below, in some cases screening may continue past age 65. The new guidelines reaffirm recommendations from the previous guidelines, published in 2003, “against screening in adequately screened women older than age 65 years and in women who have had a total hysterectomy with removal of the cervix.” The new recommendation statement “does not apply to women who have received a diagnosis of a high-grade precancerous cervical lesion or cervical cancer, women with in utero exposure to diethylstilbestrol, or women who are immunocompromised (such as those who are HIV-positive).”

When should screening start?

The USPSTF recommends screening for cervical cancer in women starting at age 21, regardless of sexual history, but against screening in younger women “because the evidence shows no net benefit.”

When should screening stop?

Women who have been adequately screened for cervical cancer can stop screening at age 65. The guidelines point out that the American Cancer Society (ACS), the American Society for Colposcopy and Cervical Pathology (ASCCP), and the American Society for Clinical Pathology “define adequate prior screening as three consecutive negative cytology results or two consecutive negative HPV results within 10 years before cessation of screening, with the most recent test occurring within 5 years.”

Screening may be indicated in older women who have never been screened for cervical cancer or inadequately screened. In addition, “certain considerations may support screening in women older than age 65 years who are otherwise considered [to be at] high risk (such as women with a high-grade precancerous lesion or cervical cancer, women with in utero exposure to diethylstilbestrol, or women who are immunocompromised),” the Task Force noted.

“Women choosing co-testing to increase their screening interval (and potentially decrease testing) should be aware that positive screening results are more likely with HPV-based strategies than with cytology alone and that some women may require prolonged surveillance with additional frequent testing if they have persistently positive HPV results,” according to the guidelines. “Because HPV test results may be positive among women who would otherwise be advised to end screening at age 65 years on the basis of previously normal cytology results alone, the likelihood of continued testing may increase with HPV testing. The percentage of U.S. women undergoing co-testing who will have a normal cytology test result and a positive HPV test result (and who will therefore require additional testing) ranges from 11% among women age 30 to 34 years to 2.6% among women age 60 to 65 years.”

What if the results of screening tests are positive?

Before answering this question, Dr. LeFevre stressed that these comments go beyond the scope of the Task Force recommendations and are based on recommendations from the ACS and the ASCCP. “The current standard of care for women who have, on cytology, atypical squamous cells of undetermined significance (ASCUS) is to do an HPV test and if the HPV test is positive, to go to colposcopy,” Dr. LeFevre said. “But if their HPV test is negative, they should have more intense screening, typically coming back at 6 months and 1 year.” Changes in the ACS/ASCPP guidelines now call for women who have ASCUS but who are HPV negative to continue with routine screening.

“You’re treated as normal basically because your chances of having something bad are really no greater than somebody who had a normal Pap smear and a negative HPV. So in the context of a negative HPV, both ASCUS and normal cytology would be treated the same. That’s new. That’s not in the Task Force, but it is in the ACS guideline,” Dr. LeFevre said.

He added that the ACS guidelines also advise against colposcopy for women over 30 who have a normal cytology and are HPV-positive, recommending instead one of two options. One option would be retesting in a year and, if negative, then returning to routine screening. “So you have to be positive 2 years in a row for HPV to go to colposcopy if your cytology is normal,” he noted.

“The other option would be to have specific genotype testing for HPV, and if you are positive for HPV 16 or 18, to go straight to colposcopy.” The genotype testing “is a step beyond the usual HPV screening,” Dr. LeFevre said, and would involve “taking another sample from the cervix.” He added that genotype testing is not widely available, although the new recommendation may mean that more centers may start to offer it. “But right now the strategy for many women will be to wait a year, repeat the test, and only if you are positive 2 years in a row, to go to colposcopy.” ■