Women in the United States should start cervical cancer screening at age 21 and most do not need an annual Pap smear, according to new guidelines issued on Friday that aim to reduce the risk of unnecessary treatment.

The guidelines from the American College of Obstetricians and Gynecologists or ACOG now say women younger than 30 should undergo cervical cancer screening once every two years instead of an annual exam. And those age 30 and older can be screened once every three years.

The recommendations are based on scientific evidence that suggests more frequent testing leads to overtreatment, which can harm a young woman's chances of carrying a child full term.

Overtreatment of minor abnormal pap tests in young women and adolescents can lead to consequences such as preterm labor in some cases. It increases the risk, said Dr. Thomas Herzog of Columbia University in New York, who is chairman of an ACOG subcommittee on gynecologic cancers.

Preterm delivery has become a huge problem in the United States that has potential serious consequences for the unborn fetus, said Dr. Jennifer Milosavijevic, a specialist in obstetrics and gynecology at Henry Ford Health System in Detroit, who supports the guideline changes.

AVOIDING UNNECESSARY PROCEDURES

These new guidelines will allow us to avoid doing unnecessary procedures on the sexually active adolescent female, she said in an e-mail.

The guidelines are unlikely to be met with the kind of rebellion that accompanied new breast cancer screening guidelines this week, which were largely based on computer projections, Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society, said in a telephone interview.

There is a lot more agreement about the science of cervical cancer screening, Lichtenfeld said.

Prior recommendations called for annual cervical cancer screening to start three years after a women first becomes sexually active, or by age 21. Although the rate of HPV infection is high in this population, rates of cervical cancer are very low.

Herzog said the new recommendations are based on studies that suggest starting screening earlier than age 21 causes more harm than benefit.

We were overdiagnosing and overtreating adolescents and very young women, Herzog said in a telephone interview.

Cervical cancer is a slow-growing cancer caused by exposure to certain strains of the human papillomavirus (HPV), a common sexually transmitted disease among women and men.

Women do not get cervical cancer first. They acquire HPV, the sexually transmitted virus that causes precancerous abnormalities of the cervix and cervical cancer. It takes years to progress from an HPV-infection to full-blown cervical cancer, Milosavijevic said.

For that reason, she said changing the screening interval will not mean more cervical cancers will be missed. She said most deaths from cervical cancer in the United States happen in people who are screened infrequently, or not at all.

The take-home message for women is that you should still get your pap smear screening, Milosavijevic said.

HPV is the most common sexually transmitted disease in the world. About 20 million Americans currently are infected with HPV, according to the CDC.

In the past 30 years, cervical cancer rates in the United States have fallen by more than half, due in large part to widespread use of cervical cancer screening.

Medicine