New cervical Ca screening guidelines recommend less frequent assessment

“Women who have any other abnormality should be managed according to existing guidance from the ASCCP,” Dr. Kaunitz advises.³ “After spontaneous regression or appropriate treatment, women who have a history of cervical intraepithelial neoplasia (CIN) grade 2 or higher should continue routine screening for at least 20 years, even if this extends screening past the age of 65 years.”

Guidelines emphasize the harms of frequent screening

Both sets of guidelines mention the potential “harms” of screening. For example, the ACS/ASCCP/ASCP guidelines point out that most HPV infections and many cases of CIN 1 and CIN 2 are transient, unlikely to progress or develop into cancer.

“The potential harms associated with detecting these transient lesions include the anxiety associated with a ‘positive’ cancer screening test, potential stigmatization from the diagnosis of a sexually transmitted infection, discomfort from additional diagnostic and treatment procedures, bleeding from treatment, and, longer term, an increased risk of pregnancy complications such as preterm delivery due to treatment,” according to the guidelines. “Having a positive test at any point in one’s life may contribute to a perception of an increased risk of cancer, and a subsequent desire for more testing, further increasing the likelihood of another positive test.”²

The USPSTF takes this concern for potential harms a step further and emphasizes the possibility of “overtreatment” when HPV testing is used as part of a cervical cancer screening strategy: “Positive screening results are more common with strategies that include HPV testing than with strategies that use cytology alone. Therefore, the likelihood of prolonged surveillance and overtreatment may increase with strategies that incorporate HPV testing.”¹

However, the ACS/ASCCP/ASCP noted that screening models indicate that co-testing of women 30 years and older at 5-year intervals results in fewer colposcopies (thereby reducing harms) and carries “a similar or slightly lower cancer risk, compared with cytology alone performed at 3-year intervals.” That is because 5-year intervals reduce the number of screens in a woman’s lifetime, thereby detecting fewer transient HPV infections and low-grade cellular changes not destined to become cancer.

Reducing the number of colposcopies

The guidelines aim to reduce the number of women referred to colposcopy for cytologic abnormalities or HPV-positive results. In formulating the ACS/ASCCP/ASCP guidelines, the panel calculated the number of colposcopies associated with different screening intervals, noting that “screening every 3 years is associated with a lifetime prediction of about 760 colposcopies per 1,000 women, screening every 2 years with about 1,080 colposcopies per 1,000 women (a 40% increase vs screening every 3 years), and screening every year with about 2,000 per 1,000 women.”² However, the yield of high-grade CIN and cervical cancer identified during screening does not vary significantly between these intervals.

“The lifetime risk of cervical cancer in the United States in the absence of screening is projected to be approximately 31 to 33 cases in every 1,000 women,” says Tom Cox, MD, past president of ASCCP. Dr. Cox is an OBG Management contributing editor. “Screening with cytology alone every 3 years reduces this risk to 5 to 8 incident cancers per 1,000 women, and the risk drops slightly with screening every 2 years to 4 to 6 cases per 1,000 women. Annual screening further reduces this risk to about 3 cases per 1,000 women. The predicted lifetime risk of death due to cervical cancer associated with screening with cytology every 3 years, every 2 years, and annually is even lower: 0.05, 0.05, and 0.03 death per 1,000 women, respectively.”

“So there is a small reduction in the lifetime risk of cervical cancer with more frequent cytology screening,” Dr. Cox notes, “but the harms of more frequent screening were determined by both the USPSTF and the ACS/ASCCP/ASCP to far outweigh the benefit. Co-testing at 5-year intervals provides similar, or even lower, cancer risk than cytology at 3-year intervals, justifying the choice of a longer screening interval when co-testing is negative.”

Rethinking the annual exam

Many women schedule an appointment with their gynecologist each year for the express purpose of undergoing a Pap test. Now that the shortest recommended screening interval for cervical cancer is 3 years, will the annual gynecologic exam go the way of the dinosaurs?

“Absolutely,” says Neal M. Lonky, MD, MPH, clinical professor of obstetrics and gynecology at the University of California– Irvine and a member of the board of directors of Southern California Permanente Medical Group. Dr. Lonky is an OBG Management contributing editor.

“If there is no preventive health activity tied to an annual visit, I think insurers will support fewer visits, requiring less reimbursement for services, especially in HMO and PPO models. I envision more ‘virtual’ care—that is, visits that do not involve an examination, for purposes such as the dispensing of birth control pills. But I am hopeful that more education about the benefit of regular visits for other preventive measures would be possible.”