Best Cancer Test: HPV vs. Pap Smear
Study Shows HPV Test Is Better Predictor of Cervical Cancer in Older Women
Nov. 2, 2006 -- For more than 60 years the Pap smear has been the screening method of choice for cervical cancer, but it is not the best approach for assessing risk in older women, new research suggests.
Findings from a large, Danish study provide compelling evidence that testing for human papillomavirus (HPV) is more effective for identifying older women with a high risk of developing cervical cancer.
Cervical cancer is caused by HPV infection, which is spread through sexual contact. Two specific types -- HPV 16 and HPV 18 -- are believed to be responsible for up to 70% of cases worldwide.
HPV is fairly common among younger women, but in most cases infection is transient and does not pose a health risk.
Infection tends to be rarer and more persistent in older women, however, and infection later in life is increasingly recognized as a major risk factor for cervical cancer.
In the newly reported study, women between the ages of 40 and 50 who tested positive for HPV had a greater than 20% chance of developing cervical cancer within 10 years. Most of these older women with positive HPV tests had concurrent Pap smear results that were negative.
"We have documented that a single HPV test can actually predict older women at risk for cervical cancer better than a single Pap smear can," says researcher Susan Kruger Kjaer, MD.
"Based on these results, we feel that an HPV test would benefit older women, whether or not that test is used in conjunction with Pap smears, or used by itself as an initial screen."
Better Long-Term Predictor
Kjaer and colleagues from the Danish Cancer Society compared HPV and Pap smear screening in two Danish populations -- 8,656 women between the ages of 22 and 32, and 1,578 women between the ages of 40 and 50.
Cervical samples were collected from all of the women for HPV testing, and they all had multiple Pap smear tests over 10 years of follow-up.
In a pap test, cells from a woman's cervix are sampled and examined under a microscope for abnormalities.