Background: Follow-up care is controversial for women with a colposcopic diagnosis of cervical human papillomavirus (HPV) or cervical intraepithelial neoplasia (CIN) grade 1. The inability to exclude CIN 2 through the use of colposcopy, and confusion about the natural course of HPV and CIN 1, add to this controversy. The courses of HPV and CIN 1 are difficult to determine because differentiating CIN 1 from nonneoplastic HPV is challenging. Previous recommendations for the management of women with HPV or CIN 1 consistent with the initial cytology were to repeat cervical cytology at six and 12 months or screen for high-risk HPV at 12 months. However, this strategy did not take into consideration the patient's age or the presence or absence of high-risk HPV during the initial assessment. Pretorius and colleagues assessed the risk and presentation of CIN 3 or cancer after a colposcopic diagnosis of CIN 1 or less.

The Study: The data evaluated were from the Southern California Permanente Medical Group–Fontana cervical cancer prevention file from 1998 through 2005. Women diagnosed with CIN 1 or less by colposcopy-directed biopsy were given annual cytology smears and evaluated for the presence of high-risk HPV. Colposcopy was repeated if cytology showed either atypical squamous cells favoring high-grade squamous intra-epithelial lesions or atypical squamous cells of undetermined significance with high-risk HPV present. It also was repeated every two years if cervical cytology was normal and high-risk HPV was present. If atypical squamous cells of undetermined significance were present on cytology, and the high-risk HPV test was negative at the first follow-up visit, cytology and a high-risk HPV test were repeated in one year. If the cervical cytology was normal, and the high-risk HPV test was negative for two consecutive examinations, the women returned to their routine screening schedule. CIN 3 or cancer diagnosed by cervical biopsy was recorded, and the different rates were calculated for each of the treatment strategy groups. Age at the time of initial colposcopy also was recorded.

Results: There were 3,791 participants in the study, and the mean follow-up period was 26.3 months. Of the women who had CIN 1 or less on colposcopy, 1.9 percent were subsequently diagnosed with CIN 3 or cancer. The presence of high-risk HPV on the initial examination was more likely to be associated with subsequent CIN 3 and cancer. Women who were 30 years or older were more likely to have subsequent CIN 3 or cancer than younger women.

When patients were diagnosed with CIN 3 or cancer, 97.8 percent had high-risk HPV present and 91.3 percent had abnormal cervical cytology. Women with normal cervical cytology and high-risk HPV were significantly less likely to be diagnosed with subsequent CIN 3 or cancer than those with abnormal cervical cytology and high-risk HPV.

Conclusion: Annual cytology and HPV testing is appropriate for women who have been diagnosed with CIN 1 or less. If high-risk HPV is present and cervical cytology is abnormal, patients should have colposcopy. If high-risk HPV is present and cervical cytology is normal, patients should have colposcopy at least every two years. Women with subsequent normal cytology and a negative high-risk HPV test for two consecutive years can return to a routine screening schedule.