Objective: Current US guidelines for cotesting recommend that the large numbers of women who test Pap-negative, but human papillomavirus (HPV)-positive, return in 1 year, and those who remain HPV-positive or have low-grade squamous intraepithelial lesion (LSIL) or worse Pap results be referred for colposcopy. However, the performance of these guidelines in routine clinical practice has not been evaluated.
Methods: We estimated cumulative 5-year risks of cervical intraepithelial neoplasia grade 3 or worse (CIN 3+) among 32,374 women aged 30 to 64 years with HPV-positive/Pap-negative cotest results at Kaiser Permanente Northern California during 2003 to 2010.
Results: The 5-year CIN 3+ risk after an HPV-positive/Pap-negative cotest result, which was found in 3.6% of women, was 4.5% (95% confidence interval [CI] = 4.2%-4.8%). The 5-year cancer risk was 0.34% (95% CI = 0.26%-0.45%), and half of the cases were adenocarcinoma. Overall, 48% of the women remained HPV-positive on return (median = 418 days after baseline), a percentage that varied little over ages 30 to 64 years. At the return after a baseline HPV-positive/Pap-negative result, almost every repeat cotest result predicted greater subsequent 5-year CIN 3+ risk than the same cotest result had at baseline (HPV-positive/LSIL, 9.2% vs 6.1%, p = .01; HPV-positive/atypical squamous cells of undetermined significance [ASC-US], 7.9% vs 6.8%, p = .2; HPV-positive/Pap-negative, 7.4% vs 4.5%, p < .0001; HPV-negative/LSIL,1.7% vs 2.0%, p = .8; HPV-negative/ASC-US, 2.9% vs 0.43%, p = .0005; HPV-negative/Pap-negative, 0.93% vs 0.08%, p < .0001).
Conclusions: Using the principle of "equal management of equal risks," women testing HPV-positive/Pap-negative had a subsequent CIN 3+ risk consistent with risk thresholds for a 1-year return. However, on returning in approximately 1 year, about one-half of women will be referred for colposcopy because of continued HPV positivity or Pap abnormality. Clinicians should keep in mind that cotest results at the return after a baseline HPV-positive/Pap-negative finding are riskier than the same baseline cotest results in the general population, supporting intensified clinical management at return testing.