Leading Health Organizations Revise Cervical Cancer Screening Guidelines
Last week, several health organizations issued new cervical cancer screening guidelines that extend the time interval between screening tests for most women. Based on comprehensive reviews of available data—including NCI-funded research—the new guidelines seek to maximize the benefits of current screening tests while minimizing their potential harms.
The United States Preventive Services Task Force (USPSTF) released one set of guidelines, and a group of three health organizations—the American Cancer Society (ACS), the American Society for Colposcopy and Cervical Pathology (ASCCP), and the American Society for Clinical Pathology (ASCP)—released a second set. Although the two sets of guidelines were developed independently, their recommendations are consistent.
The ACS/ASCCP/ASCP guidelines were published jointly in CA: A Cancer Journal for Clinicians, Journal of Lower Genital Tract Disease, and American Journal of Clinical Pathology on March 15. The USPSTF recommendation statement appeared the same day in the Annals of Internal Medicine.
A better understanding of the role of persistent oncogenic human papillomavirus (HPV) infection in the initiation and progression of cervical cancer, as well as results from numerous studies evaluating the performance of HPV DNA testing in screening, prompted this re-evaluation of cervical cancer screening guidelines.
"These recommendations ensure that women receive the benefits of testing while minimizing the harms," said Dr. Diane Solomon of the Breast and Gynecologic Cancer Research Group in NCI's Division of Cancer Prevention, who helped develop the ACS/ASCCP/ASCP guidelines. "We're screening less often, but we're screening smarter."
The guidelines apply to women who have a cervix, whose immune systems have not been compromised, and who were not exposed in utero to substances such as diethylstilbestrol (DES) that would increase their risk. The recommended intervals are for women with normal test results; those with abnormal test results need to be followed more frequently.
When to Screen
Both sets of guidelines call for screening to start at age 21, regardless of when a woman becomes sexually active. The groups concluded that most HPV infections, which are spread through sexual contact, and cervical changes that are detected before this age will likely resolve on their own and not become cancerous.
The recommendations also extend the time interval between tests. Women ages 21 to 65 should be screened with the Pap test every 3 years. Women ages 30 to 65 who have the HPV DNA test and the Pap test (co-testing) can be screened every 5 years. ACS, ASCCP, and ASCP preferred co-testing over the Pap test alone, whereas the USPSTF deemed co-testing acceptable based on recently published data, including a study of women enrolled in the co-testing program at Kaiser Permanente Northern California, which was conducted in collaboration with NCI researchers. (See "HPV and Pap Co-Testing Safely Extend Cervical Cancer Screening Intervals".)
Pap tests have been done yearly in the past, but we now know that annual screening is not needed and can lead to harm from treatment of cell changes that would never go on to cause cancer.
—Dr. Debbie Saslow
—Dr. Debbie Saslow
"This is good news for women," said USPSTF Chair Dr. Virginia Moyer, professor of pediatrics at the Baylor College of Medicine, in a press release, "because evidence shows that an annual Pap smear is not necessary to prevent deaths from cervical cancer. Screening every 3 years [with the Pap test] saves the same number of lives as annual screening, but with half the number of colposcopies and fewer false-positive tests."
"Pap tests have been done yearly in the past, but we now know that annual screening is not needed and can lead to harm from treatment of cell changes that would never go on to cause cancer," said Dr. Debbie Saslow, first author of the ACS/ASCCP/ASCP guidelines and director of breast and gynecologic cancer for the ACS, in a statement. "With the addition of the HPV [DNA] test, we can test even less frequently, as the risk of precancer and cancer when both tests are negative is so low."
When Not to Screen
Women who have had a hysterectomy and no longer have a cervix should not be screened, according to the new guidelines. Likewise, women over age 65 should not be screened if they have had three consecutive negative Pap tests or two consecutive negative co-tests within 10 years, and the last test was administered within 5 years. However, women with a history of cervical precancer or a cancer diagnosis should continue screening as recommended by their physician, according to the new guidelines, for at least 20 years, even if it means testing after age 65.
In addition, the guidelines recommend against using the HPV DNA test alone in women of any age or using co-testing in women younger than 30 years of age because, HPV is common in young women, but the vast majority of HPV infections are transient. "HPV testing kicks in as a primary screening tool at age 30 as the prevalence of HPV infection declines and the underlying risk of there being something clinically relevant is higher with a positive HPV result," said Dr. Solomon.
Women who have had a previous diagnosis of cervical cancer or precancer or who are at higher risk for cervical cancer, including women with compromised immune systems or who were exposed to DES before birth, may need more intensive or alternative screening.
Whether gynecologists and family physicians will follow the new guidelines remains to be seen and will likely be the subject of future research. "We need to emphasize education," said Dr. Solomon. "As clinicians understand the rationale and the scientific basis behind these recommendations, I think they will be accepted and implemented. But it is going to take some time.
"Decades ago, we did a very good job of inculcating in clinicians' minds and in women's minds that they needed an annual Pap test. And we were so successful that it is hard to move people past that now," Dr. Solomon continued. "Cervical screening is best done using the most sensitive testing strategy at the longest safe interval. This provides safety for women and reduces the 'noise' of over-screening. When you find things that are not really clinically relevant but that need to be worked up, that causes anxiety and needless additional procedures."
Regardless, the authors of both sets of guidelines stressed that the greatest gains in reducing the incidence and mortality of cervical cancer will be attained only by increasing access to screening among women who are unscreened or screened too infrequently.