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 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
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
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