Accuracy of colposcopy management to detect CIN3 and invasive cancer in women with abnormal screening tests: results from a primary HPV screening project from 2006 to 2011 in Wolfsburg, Germany.

ABSTRACT

OBJECTIVE: Combining HPV and Pap screening achieves very good risk stratification and sensitive detection of CIN3 and cancer (CIN3 +), but poorer specificity, and may result in an increased risk of glandular and new lesions during follow-up. We examined if this phenomenon may compromise the accuracy of colposcopy. METHODS: As part of a primary HPV screening pilot project comprising 19,624 participants aged over 30 years, the failure rate to detect CIN3 at first visit was measured over a five-year period to assess the quality of colposcopy as an overall management concept. Management relied on excisional biopsies in all HSIL cytology or major findings on colposcopy, endocervical assessment in type 3 transformation zones (TZ) and guided biopsies in type 1 or 2 TZ. RESULTS: Of 667 women referred for colposcopy because of atypical Pap smears and/or HPV persistency, 171 were diagnosed with CIN3+. All 18 cancers and 140/153 CIN3 cases were diagnosed at the first visit. Of 13 CIN3 observed during follow-up, five were classified as new cases, five as definite and three as probably colposcopy failures, giving a failure rate of 4.7% (8/171). Only three failures were related to false-negative punch biopsies while five occurred because of false-negative endocervical assessment in type 3 TZ. CONCLUSIONS: Colposcopy management following defined pathways was safe in this HPV screening program with an acceptable failure rate. Further improvements may depend on developing better methods for endocervical assessment rather than for ectocervical biopsies.