Switch from cytology-based to human papillomavirus test-based cervical screening: implications for colposcopy.

Human papillomavirus (HPV) testing is more sensitive than cytology; some cervical cancer prevention programs will switch from cytology to carcinogenic HPV test-based screening. The objective of our study is to evaluate the clinical implications of a switch to HPV test-based screening on performance and workload of colposcopy. Women in the population-based, 7-year Guanacaste cohort study were screened at enrollment using cytology. We also took another specimen for HPV DNA testing and collected magnified cervical photographic images (cervigrams). A final case diagnosis (≥cervical intraepithelial neoplasia [CIN] grade 3, CIN2, <CIN2) was assigned at exit. Using the cervigram as a surrogate of colposcopy impression, we evaluated the impact of changing screening method from cytology to carcinogenic HPV testing on the distribution of enrollment colposcopic impression and on the predictive values of positive and negative colposcopic impressions for the cumulative 7-year detection of ≥CIN2 and ≥CIN3. A program based on immediate colposcopic referral after positive HPV would immediately identify as high risk more of the cumulative ≥CIN2 cases than conventional cytology, because of an increased number of referrals. However, the proportion of women that would have visible lesions at referral to colposcopy and the sensitivity versus specificity trade-off of the colposcopic impressions would be similar to programs using cytology (≥ atypical squamous cells of unknown significance [ASCUS]) for referral. The major concern with switching from cytology to more sensitive HPV screening is management of the many HPV-positive women, including those with still nonvisible ≥CIN2 lesions. Our data support the need for a nonvisual diagnostic method to guide management and treatment of HPV-positive women.