Age-old practice of annual screening exams for cervical cancer may be harmful than helpful

University of North Carolina at Chapel HillJul 10 2013

For decades, women between the ages of 21 and 69 were advised to get annual screening exams for cervical cancer. In 2009, however, accumulating scientific evidence led major guideline groups to agree on a new recommendation that women be screened less frequently: every three years rather than annually.

Despite the revised guidelines, about half of the obstetrician-gynecologists surveyed in a recent study said they continue to provide annual exams - an outdated practice that may be more harmful than helpful, said Drs. Russell Harris and Stacey Sheridan of the Cecil G. Sheps Center for Health Services Research at the University of North Carolina at Chapel Hill.

"Screening is not the unqualified good that we have advertised it to be," they wrote in an editorial titled, "The Times They (May Be) A-Changin': Too Much Screening is a Health Problem." The editorial accompanied a research study reviewing physician practices around cervical-cancer screening and vaccination for human papilloma virus (HPV), which has been linked to cervical cancer.

The study, "Physicians Slow to Implement HPV Vaccination and Cervical Screening Guidelines," was published July 9 in the American Journal of Preventive Medicine.

"Screening for cervical cancer and other cancers such as breast and prostate, has clear potential for harms as well as benefits, and these must be carefully weighed before a rational decision about screening can be made," wrote Harris and Sheridan, who are professor and assistant professor of medicine, respectively, at UNC's School of Medicine. They also hold adjunct appointments at UNC's Gillings School of Global Public Health.

The study noted physicians said they were comfortable with longer testing intervals, but were concerned their patients might not come in for annual check-ups if Pap tests, the screening test for cervical cancer, were not offered. The problem, Harris said, is that annual Pap tests produce more abnormal results leading to additional, invasive testing that itself bring risks.

"Many women have 'abnormal' [Pap test] findings that are not cancer, but may be a 'cancer precursor.' We know that the great majority of these abnormal findings would never progress to actual invasive cancer, yet these women are referred" for further, more invasive testing, Harris said.

One such test, called a "colposcopy," [cohl-PAH-scoh-pee], involves examining the cervix for possibly cancerous lesions, followed frequently by a biopsy, i.e., taking a small sample of the lesion, which can cause pain and bleeding, as well as potential psychological harm. "The screening test itself can raise concern about dreaded cancer; a positive screening test heightens this worry; finding a cancer precursor, even one of uncertain importance, just increases worry further," they wrote.

The authors recognize the important benefit of screening for cervical and other cancers, but "screening every three years [for cervical cancer] retains about 95 percent of the benefit of annual screening, but reduces harms by roughly two-thirds." Less-frequent screening also reduces costs significantly in terms of patient and physician time and laboratory testing supplies and other resources.

The newest cervical-cancer and HPV screening recommendations were released in March 2012, too recent to have been included in the July 9 study. Women should still begin Pap tests at age 21 and every three years afterward, but women between the ages of 30 and 65 may choose to extend the Pap test interval to every five years, provided they also get an HPV test, according to the U.S. Preventive Services Task Force and the American Cancer Society, among others. However, the authors added, "the debate about a do-less approach to screening-for cervical cancer and other conditions as well-is ongoing."