Pap Tests Effective, But They Should Not be Overdone

A Pap test is a safe and effective way to prevent cervical cancer or find it early by detecting abnormal cells on the cervix that may become cancerous if not treated appropriately. But conducting the test more often than necessary may do more harm than good, experts say. According to United States Preventive Services Task Force (USPSTF) guidelines, Pap testing every three years, rather than every year, is reasonable for most women.

“Cervical cancer grows very slowly,” explains Janet Pregler, M.D., director of the Iris Cantor-UCLA Women’s Health Center. “For most women, the likelihood that we will detect a problem within one year is exceedingly low, but the risk that we will provide unnecessary treatment for a benign condition increases when we overscreen.”

Of approximately 55 million Pap tests performed in the U.S. each year, about 3.5 million, or 6 percent, are abnormal, and fewer than 13,000 women are diagnosed with cervical cancer.

Current guidelines recommend that women should begin receiving regular Pap tests at age 21 and continue with testing until age 65. After three years of normal results, most women can increase the screening interval from one to three years. Women older than 30 years who have negative Pap and human papillomavirus (HPV) tests can also decrease screenings to once every three years. Women with impaired immune systems, such as women with human immunodeficiency virus (HIV) or those on immunosuppressant medications, as well as women with high-risk sexual behaviors or those exposed to diethylstilbestrol (DES) before birth, are at greater risk for developing cervical cancer and may be advised to continue annual Pap testing. Women younger than 21 years, regardless of sexual history, should not be screened.

“Pap-test abnormalities are common in teenage girls, but most of the abnormalities will clear up on their own,” Dr. Pregler says. “It’s not a good idea to perform unnecessary procedures on a young woman’s uterus,” she says. She adds that risk for cervical cancer later in life is reduced when teens receive the HPV vaccine before they become sexually active.

Cristina Almeida, M.D., is part of a team studying ways to improve appropriateness of cervical-cancer screening for women. Dr. Almeida and others at UCLA are comparing current USPSTF guidelines with current practices at UCLA to identify key areas for improvement with the goal of educating physicians and patients about the scientific evidence behind the new guidelines.

“Given the complexities of cervical cancer screening guidelines, every woman should really have an open discussion with her physician to decide what sort of screening frequency is most appropriate based on her individual risk,” Dr. Almeida says.

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