WEDNESDAY, March 14 (HealthDay News) -- The annual Pap smear may soon be a thing of the past, since new guidelines issued Wednesday say that most women need the cervical-cancer screening only once every three years.

In its first update since 2003, the U.S. Preventive Services Task Force (USPSTF) said a yearly Pap smear isn't necessary for women aged 21 to 65, and that women younger than 21 don't need the test at all because evidence indicates screening doesn't lower cervical-cancer rates or deaths in this youngest group.

Screening every three years after age 21 saves the same number of lives as annual screening, with half the number of biopsies and fewer false-positive results, according to the USPSTF, an independent panel of health experts that issues guidelines based on periodic reviews of scientific evidence. The guidelines were published online in the Annals of Internal Medicine.

"We've moved into an age of less is more, so this is just fine-tuning," said Dr. Diana Contreras, division director of obstetrics and gynecology at Long Island Jewish Medical Center in New Hyde Park, N.Y. "Before we used to have a very large hammer, and now our hammer is getting more precise." Contreras was not part of the panel.

More than 12,000 women are diagnosed with cervical cancer each year and 4,000 die from it, according to the U.S. National Cancer Institute. Pap smears detect abnormalities in cells scraped from the opening of the cervix.

The new guidelines, which are broken down by age group and health history, also say:

• Women between ages 21 and 65 can safely extend cervical screenings to every five years if they undergo a human papilloma virus (HPV) test at the same time as their Pap smear. HPV infections, many of which are sexually transmitted, are one of the predominant causes of cervical cancer.
• Women older than 65 who have had prior screenings and are otherwise not at high risk no longer need Pap smears. Routine screening should continue, however, at least 20 years after resolution of any high-grade precancerous lesions.
• Women under 30 should not undergo HPV testing since the infection is prevalent in younger women but often clears up without treatment.
• Women who have undergone a hysterectomy with a removal of the cervix and who have no history of cancerous or precancerous cervical lesions don't need to be screened, since the risks associated with screening outweigh the benefits in this group.

"The most important point we want to make is that the highest-risk women are those who have never been screened or haven't been screened in over five years," said Dr. Wanda Nicholson, one of the lead authors of the guidelines and associate professor of gynecology and obstetrics at the University of North Carolina School of Medicine in Chapel Hill.

Contreras agreed. "This is a cancer we could get rid of in this country if we were able to screen everyone who needs it," she said, adding that women should continue annual visits to their gynecologists to monitor other aspects of their reproductive health.

But this latest iteration of USPSTF screening guidelines probably isn't the last word on the subject, the experts said. The long-term effects of widespread Gardasil vaccinations to prevent HPV infection among adolescents and young adults have yet to be seen, Contreras and Nicholson said. The U.S. Food and Drug Administration approved Gardasil in 2006.

"Since I was a [medical] resident, guidelines have changed multiple times," Contreras said. "We also understand how much more common HPV is. The idea is to do the appropriate procedures on the appropriate patients."

Three other national health groups -- the American Cancer Society, American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology -- simultaneously issued joint cervical-cancer-prevention guidelines that were in line with those released by the USPSTF.

More information

The U.S. National Institutes of Health has more about cervical cancer.