Single HPV Test Predicts the Risk of Cervical Cancer for 18 Years || NCI Cancer Bulletin for August 7, 2012 - National Cancer Institute

NCI Cancer Bulletin for August 7, 2012 - National Cancer Institute
Single HPV Test Predicts the Risk of Cervical Cancer for 18 Years

Single HPV Test Predicts the Risk of Cervical Cancer for 18 Years

In a group of more than 20,000 women, the human papillomavirus (HPV) DNA test more accurately predicted the risk of developing cervical cancer over an 18-year follow-up period than the Pap test.
Although both tests could identify women who were most likely to develop high-grade precancerous cervical lesions or squamous cervical cancers within 2 years of testing, only the HPV test result predicted the risk for women up to 18 years later.

Dr. Philip Castle of the American Society for Clinical Pathology and his colleagues reported their findings July 30 in the Journal of Clinical Oncology.

The authors, including researchers from NCI's Division of Cancer Epidemiology and Genetics (DCEG), used data from a study initiated by NCI and Kaiser Permanente of women who, in 1989 and 1990, underwent routine Pap testing in Portland, OR. Samples collected at the start of this study were used for Pap and HPV testing.

Recently reported research from this group also showed that HPV testing could predict risk for 18 years, but those results were based on HPV tests that are used only in research settings. These new results are based on the type of HPV tests that are used in current clinical practice.

The researchers found that the HPV test more accurately stratified women by their risk of developing cervical cancer than the Pap test. Over the 18-year follow-up period, 199 women were diagnosed with cervical intraepithelial neoplasias grade 3 or cervical cancer (CIN 3+); more of these cases developed in those with a positive HPV test (112 women) than in women who had an abnormal Pap test (65 women).
Conversely, fewer cases of CIN 3+ developed over the follow-up period in women with a negative HPV test at the start of the study than in women with a normal Pap test taken at the same time (87 women versus 134 women).

Current screening guidelines recommend that most women aged 30 to 65 be tested for high-risk HPV types in conjunction with a Pap test every 5 years.

DCEG's Dr. Sholom Wacholder, senior author on the study, said that data from the study showed that, for women aged 30 or older, the 3- and 5-year risks for precancer or cancer after a negative HPV test and negative Pap test were very low, consistent with the guidelines.

Risk of Developing Precancer or Cancer
after Negative HPV and Pap Tests in Women Older than 30

	CIN 2+	CIN 3+
3-year risk	0.23 percent	0.08 percent
5-year risk	0.36 percent	0.16 percent

Recent reports have suggested that some doctors worry that if they offer HPV and Pap co-testing every 5 years in accordance with the new guidelines, women might go several more years between screenings.

"HPV testing is a powerful predictor of cervical cancer risk. This work provides evidence to support extended screening intervals after negative HPV and Pap tests," said Dr. Wacholder. "The very low risk over 10 years in women with a single negative HPV test provides a reassuringly large margin of safety."
This research was supported in part by NCI's Intramural Research Program.