CHICAGO -- Millions of women whose cervical-cancer results come back inconclusive could enjoy the benefits of a more convenient follow-up treatment under new Pap test guidelines issued by a panel of experts.

The guidelines could mean fewer return visits and less anxiety for women across the country. The development reflects doctors' better understanding in recent years of the chief cause of cervical cancer, the human papillomavirus, or HPV.

Currently, many of the estimated 2.5 million American women who receive abnormal but inconclusive results each year are given at least two follow-up Pap tests within the next 12 months; or a colposcopy test, in which the cervix is examined and sometimes biopsied; or a test for HPV.

The new guidelines say HPV testing alone should be the preferred method for many women. In many cases, the HPV test can be done from the Pap test sample.

If the HPV test is negative for the riskiest forms of the virus -- as is the case in about half of these women -- the patient can be virtually assured she does not have cancer and does not need more follow-up testing, the experts said.

By some estimates, that could save hundreds of millions of dollars a year in health care costs.

Experts create guidelines

The guidelines were created at a conference last year sponsored by the American Society for Colposcopy and Cervical Pathology. Participants included representatives from 29 professional groups, including the American Cancer Society and the American College of Obstetricians and Gynecologists.

"It should set a standard for how women with abnormal screening tests should be handled," said a co-author of the guidelines, Dr. L. Stewart Massad of Chicago's Cook County Hospital.

The guidelines, which appear in Wednesday's Journal of the American Medical Association, reflect how a few high-risk strains of HPV are the primary cause of cervical cancer.

"Right now, there's a lot of overdiagnosis, a lot of extra unneeded follow-up tests that are being done, which are a tremendous health care cost but also a tremendous cost to the women in terms of anxiety, time and discomfort," said the cancer society's Debbie Saslow. If many women with inconclusive results can be reassured, "that will be a big benefit for society."

Pap tests plus an office visit may cost roughly $40, compared with about $100 for an HPV test, Saslow said, while colposcopy can cost $300 or more.

An estimated 50 million U.S. women a year undergo a Pap test, in which cells are scraped from the cervix and examined under the microscope for abnormalities that could mean cancer.

When a Pap test comes back abnormal, "every patient that I see, the first thing they think is, 'Do I have cancer and am I going to die?"' said Dr. Thomas Wright, a Columbia University pathologist and lead author of the guidelines.