Long-Term Study Sorts Out Risks For HPV Infection And Cervical Lesions.(human papillomavirus)

2001 JUL 12 - (NewsRx Network) -- More than half of sexually active young women will be infected with human papillomavirus (HPV) if they remain sexually active over three years, a University of California, San Francisco, study shows.

That risk is boosted 10-fold with each new partner.

Contrary to some previous research, the study reported in the June 20, 2001, issue of the Journal of the American Medical Association showed that once a woman is infected with HPV, she is not certain to develop benign changes in the cells of the cervix called LSIL, or low-grade squamous intraepithelial lesions. Approximately 30% of study subjects developed LSIL over a period of five years. The level of sexual activity or presence of other sexually transmitted diseases did not, as earlier studies seemed to show, increase a woman's risks of LSIL. HPV infection itself was the major identifiable cause, with an additional boost from daily cigarette smoking.

The report comes from the longest-running longitudinal study of women and HPV, a U.S. National Cancer Institute-sponsored project now in its 11th year. Anna-Barbara Moscicki, MD, UCSF professor of pediatrics, and her colleagues have followed a cohort of adolescents and young women since relatively early in their sexually active lives. Using frequent medical exams and laboratory tests, they are tracing the natural history of HPV and the benign and sometimes cancerous lesions that it causes.

Human papillomavirus is the most common sexually transmitted disease, infecting more than five million Americans each year, according to the American Social Health Association. HPV is considered to be the main cause of LSIL and other lesions in the cervix, including cancer. The American Cancer Society estimates that there will be about 12,900 new cases of invasive cervical cancer in the United States in 2001. While early detection and treatment saves many women's lives, about 4,400 will die this year from the disease.

"We know little about the progression of HPV to cervical cancer. This longitudinal study tells us something about the beginning of the story," Moscicki said. Her project continues to follow women with LSIL and with other cell changes including high-grade squamous intra-epithelial lesions (HSIL).

"Our data show that some biological and behavioral risks thought to be associated with LSIL are in fact risks for the acquisition of HPV," she said. "This report also supports earlier work from our group and others, showing that HPV is necessary but not sufficient by itself to cause these lesions. Other behavioral and biological factors must be involved, most likely persistence of the viral infection, and the woman's own immune reaction."