Type-specific persistence of human papillomavirus DNA before the development of invasive cervical cancer

Background: Infection with the human papillomavirus (HPV) has been establis hed as a cause of cervical cancer, but the association between a positive t est for HPV DNA and the risk of the subsequent development of invasive cerv ical cancer is unknown. Methods: In a study of women who participated in a population-based screeni ng program for cancer of the cervix in Sweden from 1969 to 1995, we compare d the proportion of normal cervical smears (Pap smears) that were positive for HPV DNA among 118 women in whom invasive cervical cancer developed an a verage of 5.6 years later (range, 0.5 month to 26.2 years) with the proport ion of HPV DNA-positive smears from 118 women who remained healthy during a similar length of follow-up (controls). The control women were matched for age to the women with cancer, and they had had two normal Pap smears obtai ned at time points that were similar to the times of the base-line smear an d the diagnosis of cancer confirmed by biopsy in the women with cancer. Results: At base line, 35 of the women with cancer (30 percent) and 3 of th e control women (3 percent) were positive for HPV DNA (odds ratio, 16.4; 95 percent confidence interval, 4.4 to 75.1). At the time of diagnosis, 80 of the 104 women with cancer for whom tissue samples were available (77 perce nt) and 4 of the 104 matched control women (4 percent) were positive for HP V DNA. The HPV DNA type was the same in the base-line smear and the biopsy specimen in all of the women with cancer in whom HPV DNA was detected at ba se line. None of the control women had the same type of HPV in both smears. Conclusions: A single positive finding of HPV DNA in a Pap smear confers an increased risk of future invasive cervical cancer that is positive for the same type of virus. (N Engl J Med 1999;341:1633-8.) (C) 1999, Massachusett s Medical Society.