Teen-aged and young adult women who develop low-grade, benign lesions in the cervix due to human papilloma virus (HPV) have a 95 percent or better chance that the lesions will clear up on their own and not progress to a more advanced stage, a UCSF study shows.
The results were reported on Saturday, May 4, at the annual meeting of the Pediatric Academic Societies in Baltimore. They come from the longest-running longitudinal study of adolescent and young women and human papilloma virus, a National Cancer Institute-sponsored project now in its 12th year. It is led by Anna-Barbara Moscicki, MD, UCSF professor of pediatrics and an expert in HPV and adolescent medicine at UCSF Children’s Hospital.
The researchers studied 187 adolescents aged 13 to 22 years who were diagnosed with low-grade squamous intraepithelial lesions (LSILs). The women, from a range of ethnic and socioeconomic backgrounds, were followed every four months to determine the presence of lesions. Only 4 percent of the women had persistent LSILs that had not regressed, or cleared up, after three years. Most lesions regressed within a median time of three months. A few of the original group had insufficient follow-up information to determine the outcome, leading to a statistical estimate of a 95 percent regression rate.
Other studies have shown that as many as 20 -50 percent of adult women with LSILs will have a persistent lesion or one that progresses to a higher grade. Progression of lesions is considered to be a step toward cervical cancer, so even though LSILs themselves are benign, doctors recommend that these women get frequent checkups to watch for changes in cervical cells.
Treatment is recommended if the lesion persists longer than 18-24 months or if it progresses.
“For young women in their teens and twenties, the picture is not the same,” Moscicki said. In addition to the data showing that LSILs tend to clear up spontaneously, earlier results from the longitudinal study show that young women have a relatively low chance - approximately 30 percent - of developing an LSIL within five years of infection with HPV. Her data also show that most young women infected with HPV clear the virus from their bodies, though they are likely to be re-infected if they are sexually active.
“Overall, a sexually active adolescent’s chance of developing a persistent LSIL that progresses to a more advanced stage is approximately three in 100,” Moscicki said. Based on those findings, Moscicki recommends that young women with LSIL can be followed with repeated Pap smears.
Only if the LSIL persists or progresses do they need to be referred for a more complete test, using colposcopy to search for changes in cervical cells.
One goal of this phase of the longitudinal study was to identify factors associated with persistent LSILs, versus lesions that regressed back to normal. The scientists found no association with the number of years a young woman was sexually active, the number of sexual partners, incidence of other sexually transmitted diseases, smoking cigarettes or the use of oral contraceptives.
Moscicki’s study has followed the same cohort of young women for 12 years to study the progression of human papilloma virus infection from soon after the women’s first exposure to the virus. The women receive thorough exams including colposcopy, medical treatment and health advice during three-times-a-year clinic visits. Moscicki and her colleagues use a variety of medical and laboratory-based methods to confirm diagnoses and to study changes in the cells of the cervix that lead to LSILs and in some cases to HSILs - high grade squamous intraepithelial lesions. “By studying the links between HPV and SILs, and the link between SILs and cervical cancer, we hope to be able to understand the natural history of the disease -and find better ways to treat and prevent it,” Moscicki said.