Cervical Cancer Risk Remains High Over Time After Detection Of HPV
NEW YORK (Reuters Health) - The risk of developing high-grade squamous intraepithelial cervical lesions (SILs) remains high over time after women become persistently infected with human papillomavirus (HPV), according to a report in the American Journal of Epidemiology for November 2nd.
But the risk of incident low-grade SIL wanes over time, Dr. Eduardo L. Franco, of McGill University in Montreal, and colleagues report.
Traditional cohort studies have proven that baseline HPV infection predicts cervical cancer, Dr. Franco told Reuters Health. "But we did not know the duration of this predictivity," he added.
Therefore, he and his colleagues analyzed data for 2462 women followed for up to 8 years. Cervical specimens were analyzed in Pap smears and by polymerase chain reaction testing for HPV, and the authors calculated the time dependence of the association between HPV and precancerous conditions.
Their findings show that the combination of HPV testing and Pap smear screening is better than Pap smear screening alone, the report indicates.
"Past practice was for physicians to refer any woman with equivocal cytology results for colposcopy," Dr. Franco explained. Combining the two test results can cut down the number of women at low risk being referred, while more accurately identifying those at high risk.
"If the HPV test comes back negative, and cytology shows atypical squamous cells of unidentified significance, the woman can be told to come back at 6 months and at 12 months and be tested again." He added that, because HPV infections can be transient, a positive HPV test with negative cytology can also be monitored.
"But if the HPV does not revert to negative, or if the cytology results are not normal, then she requires closer follow-up," he said. Physicians might also consider colposcopy, "even in the absence of abnormal cytological results because a high-grade lesion may not be picked up by a routine Pap smear."
For low grade SILs, the age adjusted hazard ratios for the association between HPV at enrollment decreased gradually with time, the investigators report. At 72 months, the hazard ratio was 3.96 for oncogenic HPV, and for nononcogenic types, it was 2.37.
In contrast, the hazard ratio for high-grade SIL remained constant, at 7.15 after 12 months and 6.26 after 72 months for women who tested positive for oncogenic HPV.
Source: Am J Epidemiol 2003;158:878-886. [ Google search on this article ]