Correlation of the Hybrid Capture II High-Risk HPV DNA Test Chemiluminescense Intensity from Cervical Samples with Follow-Up Histologic Results: A Cytologic/Histologic Review of 367 Cases
SM Knoepp, DL Kuebler, DC Wilbur. University of Michigan, Ann Arbor, MI; Massachusetts General Hospital/Harvard Medical School, Boston, MA
Background: The Hybrid Capture II (Qiagen) high-risk human papilloma virus (hrHPV) DNA test is an in vitro nucleic acid hybridization assay that uses chemiluminescence for the qualitative and semiquantitative detection of hrHPV in cervical samples. Results, measured in relative light units (RLUs), are reported as positive or negative based on a ratio to cutoff value (CO) calculated from positive and negative controls. The resulting ratio (RLU/CO) is recorded as negative for hrHPV if less than 1.0, positive for hrHPV if greater than 2.5, or “equivocal” (i.e., retested) if between 1.0 and 2.5.
Design: We examined the 2-year follow-up histology of cervical biopsies from cohorts of patients initially diagnosed with atypical squamous cells of undetermined significance (ASC-US) on cervical cytology: Group 1 consisted of 148 patients with “equivocal” results on the hrHPV assay, and Group 2 consisted of 148 patients with unequivocal positive results on the hrHPV assay. We next compared the chemiluminescence intensity of hrHPV tests from patients in Group 2 based on presence and severity of dysplasia found on follow-up histology. Finally, we stratified patients for risk of high-grade CIN (CIN 2/3) based on the chemiluminescence intensity of their hrHPV results.
Results: Follow-up histology was available for 85 patients in Group 1 and 98 patients in Group 2. Results of cervical biopsy, expressed as percentage of biopsied cohort, were (Group 1/Group 2): CIN 2 or 3 (16.5%/22.4%), CIN 1 (27%/23.5%) and negative or reactive (56.5%/54.1%). Subsequent high-grade (CIN 2 or 3) histologic results for patients in Group 2 based on chemiluminescence intensity were (quartile lowest to highest): 24%, 22.2%, 22.7%, and 20.8%. Patients whose hrHPV (RLU/CO) intensity were greater than 1000 (6% of cases) showed CIN 2 or 3 in 25% of cervical biopsies on follow-up.
Conclusions: While patients with “equivocal” hrHPV tests show fewer high-grade CIN lesions on follow-up biopsy compared to patients with unequivocal positive hrHPV tests, the percentage of high-grade CIN in this cohort is significant and therefore management should be similar to the unequivocal population. After an unequivocal positive hrHPV test, the hrHPV chemiluminescence intensity does not further predict the presence, absence, or degree of CIN, as patients with low RLU/CO values show similar CIN rates to those with high RLU/CO values.
Category: Gynecologic & Obstetrics
Monday, March 22, 2010 11:15 AM
Platform Session: Section D, Monday Morning