HPV DNA testing as an adjunct in the management of patients with low grade cytological lesions in Finland.

Background: Patients with recurrent low grade cytological abnormalities are at increased risk for high grade lesions. We wanted to see whether these patients could be identified by HPV DNA and pap tests.
Methods: A prospective study of 663 patients referred for a colposcopy on the basis of ASC-US or LSIL cytology. High-risk HPV DNA positivity and cytology were compared with histology.
Results: In total 65.6% samples were positive for HC2, and the overall proportion of CIN2+ lesions was 14.6%. No CIN2+lesions were found in patients testing HC2-, pap-. There were 5/97 (5.2%) high grade lesions, which were HC2-negative but pap-positive, including 1 cervical adenocarcinoma in situ. The corresponding histological sections were all positive for p16INK in immunostaining. In further analysis by PCR, 3 samples were positive for HPV DNA. High-risk HPV type 67, which is not included in the HC2 probe cocktail, was found in 1 case, and 2 cases were HPV positive but could not be typed. One CIN3 and one AIS remained HPV negative. In these 5 cases, the concomitant pap smear showed ASC-USx1, LSILx1, HSILx2 and AGCx1. During 6-month follow-up, a relatively high number of CIN2+(28/557, 5.0%) emerged from the non-CIN-CIN1 group.
Conclusions: The HC2 test or pap test alone were not sensitive enough to detect all CIN2+lesions. A relatively high number of CIN2+cases emerged from the non-CIN-CIN1 group after 6 months. Adequate follow-up of patients with mild cytological abnormalities, including a repeat pap smear taken during colposcopy and control at 6 months is underscored. Combination of hrHPV DNA and pap test should be considered, since it had high negative predictive value.