Persistent HPV infection predicts cervical cancer risk
Human papillomavirus (HPV) persistence is the pivotal event in the development of cervical cancer, and a large, long-term study now indicates that women older than 30 years who test positive for the virus should be retested every 2 years to monitor cervical cancer risk.
Although HPV infection is the main cause of cervical cancer, most infected women do not have cervical pathology, and most HPV infections in women younger than 25 years go away. Screening is recommended for women 30 years and older, but only persistently detectable infections with specific strains seem to be associated with cervical cancer risk.
To investigate the role of genotype-specific HPV persistence in predicting cervical cancer, including invasive and in situ carcinoma, a team led by Hui-Chi Chen, PhD, of the Genomics Research Center of Academia Sinica in Taipei, Taiwan, followed a community-based cohort of women aged 30 to 65 years over a period of 16 years. A total of 11,923 participants underwent HPV testing and cytology at baseline examinations in 1991 to 1992; 6,923 women were reexamined in 1993 to 1995.
Of 10,123 women who were initially cytologically normal, 68 developed cervical cancer. As the investigators reported in Journal of the National Cancer Institute, 16-year cumulative risks of subsequent cervical cancer for women with HPV16, HPV58 (without HPV16), or other carcinogenic HPV types (without HPV16 or HPV58) were 13.5%, 10.3%, and 4.0%, respectively, compared with 0.26% for HPV-negative women. Those who had type-specific persistence of any carcinogenic HPV were at much greater risk of developing cervical cancer than were those who were HPV-negative at both visits.
Although the cumulative risks of cervical cancer following persistent carcinogenic HPV infections increased with age (5.5% for women aged 30-44 years; 14.4% for women aged 45-54 years; and 18.1% for women 55 years and older), newly acquired infections were associated with a low risk of cervical cancer regardless of age.
These findings suggest that retesting a woman 2 years after an HPV infection is found can provide useful guidance as to the duration of infection and the associated risk. Because duration of infection rather than one-time infection predicts cervical cancer risk, Chen and colleagues advised that it would not be useful to repeat HPV testing more frequently than every 2 years for HPV-positive women. They recommended that HPV testing be included in cancer screening programs for the general population.