Pap test the best for cervical cancer screening

By Dr. Ananya Mandal, MDOct 20 2011

Screening for cervical cancer can save many lives. The best test remains the Pap smear test say researchers.

The Pap test - a lab exam of cells scraped from the cervix, the gateway to the uterus - is an effective way to screen young and middle-aged women - and it's only needed once every three years, say scientists advising the government. Testing for Human Papilloma Virus or HPV - the virus that causes cervical cancer is also important and the American Cancer Society and other groups say that using both tests can be an option for women over 30.

In the U.S., cervical cancer cases and death rates have fallen more than in half since the 1970s because of Pap smears. The test can find early signs of this slow-growing cancer and treat them before a tumor has a chance to develop.

So “the bar is set pretty high” for a test to replace or supplement Paps, said Dr. Evelyn Whitlock of Kaiser Permanente Northwest's Center for Health Research in Portland, Ore. A scientific review led by Dr Whitlock said that not enough is known about the benefits and especially the harms of HPV testing. The panel voted unanimously in March that there was insufficient evidence to recommend for or against HPV testing, but has continued to discuss the issue. Infections with HPV, the human papillomavirus, are very common especially in young women. They usually go away on their own and only pose a cancer risk when they last a year or more.

“A lot of people use the word 'superior' to mean it catches more cancer,” said Debbie Saslow, the cancer society's director of breast and gynecologic cancer. “But the other side of it is, does it catch more things that are not cancer? You have to weigh benefits versus harms for any screening test.” The evidence review finds little risk of cervical cancer in women under 21 and says screening below that age may be harmful. It also says screening can stop at age 65 if a woman has had adequate screening in the past and is not otherwise at high risk.

The review was published Monday in the Annals of Internal Medicine.