New Report to Lead to Revised Cervical Cancer Screening Guidelines

Article date: October 18, 2011

By Stacy Simon

A report prepared for the U.S. Preventive Services Task Force (USPSTF) finds that a newer method of Pap testing is just as effective as the conventional method.

The American Cancer Society has been recommending since 2002 that women be tested with either method. In the liquid-based Pap test, a cell sample from the cervix is placed into a special preservative liquid before it’s sent to the lab. In the conventional method, the sample is smeared directly onto a glass microscope slide. In both methods, lab technicians examine the cells under a microscope to look for cancer.

The finding is part of a review published in the Annals of internal Medicine. The USPSTF is using the review to revise its recommendations for cervical cancer screening guidelines for the first time since 2003. The draft recommendations are expected to be announced on Wednesday for public comment.

The USPSTF is expected to follow the report’s conclusion that more evidence is needed before it recommends testing for the human papilloma virus (HPV) in routine screenings. This differs from American Cancer Society early detection guidelines, which have recommended since 2002 that HPV testing can be used in combination with the Pap test in women over 30 years old.

The main issue in cancer screening in general is to weigh benefits versus potential harms from overtreatment, says Debbie Saslow, PhD, director of breast and gynecologic cancers at the American Cancer Society.

“Large studies, such as the four large randomized trials of Pap plus HPV testing evaluated by the USPSTF, tell you about benefits and harms. But reviewers use different judgments to weigh them. For example, how many unnecessary follow-up tests, in this case colposcopies, would offset the benefit of detecting one extra case of cancer: 10, 100, 250? How do you decide when the risks outweigh the benefits? In the absence of an agreed upon number, the USPSTF used their judgment to make a recommendation, and this may differ from the judgment of the ACS and other organizations. In the current publication, they conclude that the potential risks may outweigh the benefits; most other organizations disagree and recommend Pap plus HPV testing for women over 30.”

The American Cancer Society also is reviewing its cervical cancer screening guidelines as part of a periodic update. The American Cancer Society reviews new evidence on an ongoing basis and updates screening recommendations when new evidence suggests that a change may be needed. A draft will be available later this week, with the opportunity for public comment primarily by health professionals and researchers.

Until 1987, the American Cancer Society recommended that women get a Pap test every year. Since then, American Cancer Society guidelines have said it’s safe for most women to get tested every 3 years because it generally takes much longer than that, 10 to 20 years, for cervical cancer to develop.

“But most women are still getting Paps every year,” says Saslow. “Many gynecologists claim that the annual Pap is the only reason patients come in every year, and many women continue to insist on annual screening. Yet for 25 years the ACS and other respected organizations have been recommending less frequent screening based on strong evidence. This has been a very difficult message for women and health care providers to accept.”

Screening too often can lead to unnecessary procedures. Sometimes Paps find cervical changes that lead to additional testing and treatment, but turn out to be harmless. The more often women are screened, the more likely they are to be subjected to these unnecessary procedures, some of which carry risk factors of their own. The difference between the recommendation for liquid-based Pap test screening and the recommendation for Pap plus HPV testing is that in the latter case, more cancers are detected. In the case of annual Paps compared to screening every 3 years, the benefit is extremely low while the potential harms are much higher in comparison.

See our detailed guide for comprehensive information about cervical cancer.

Reviewed by: Members of the ACS Medical Content Staff

ACS News Center stories are provided as a source of cancer-related news and are not intended to be used as press releases.

Citation: Liquid-Based Cytology and Human Papillomavirus Testing to Screen for Cervical Cancer: A Systematic Review for the U.S. Preventive Services Task Force. Published online in the Annals of Internal Medicine (Vol. 155, No. 10). First author: Evelyn P. Whitlock, Md, MPH, The Center for Health Research, Portland, Oregon.