Some types of HPV cause cervical cancer. Persistent infections with these HPV types are more likely than transient infections to induce precancerous lesions. However, researchers have not fully quantified the risks of precancerous lesions associated with persistent versus transient infections.

To determine those risks, Ana Cecilia Rodríguez, M.D., of the National Cancer Institute in Bethesda, Md., and colleagues performed a study of 2,655 randomly selected sexually active women living in Costa Rica. All of the women underwent cytology-based cervical cancer screening (Pap smears) every 6 to 12 months as well as DNA-based HPV tests.

Of the study participants, 1,013 women had HPV infections at the start of the study and 599 of them were infected with a strain that can cause cervical cancer. (Some women were infected with two or more cancer-causing types, leading to 800 total infections in the analysis.)  More than half of the infections with cancer-causing HPV types cleared within 6 months, and 67 percent cleared by 12 months. Only 4 percent of the infections with cancer-causing HPV types led to precancerous lesions, although that figure rose to 21 percent in women whose infections persisted beyond 12 months.

"These data suggest that, when possible, a patient with a normal cytology and initial positive HPV result should be managed with watchful waiting because a 12-month follow-up can safely exclude more than 50 percent of infections as transient," the authors write.

This research was published  March 25, 2008 in the Journal of the National Cancer Institute.

Note: If no author is given, the source is cited instead.

• Cervical Cancer
• Cancer
• Women's Health
• Men's Health
• Kidney Disease
• Cystic Fibrosis

• HPV vaccine
• Pap smear
• HPV
• Cervical cancer
• Sexually transmitted disease
• Trichomoniasis