The clinical value of digene hybrid capture HPV DNA testing in a referral-based population with abnormal pap smears.

PURPOSE OF INVESTIGATION

The hybrid capture human papillomavirus (HPV) DNA assay is offered by the manufacturer to assist clinicians with patients with ASCUS pap smear results to assess the risk factor and to potentially direct follow-up of these patients. In our practice, a gynecologic oncology practice that has a referral based population with abnormal pap smears, our purpose was to evaluate the patients referred with all grades of abnormal cervical cytology.

METHODS

One hundred consecutive patients who were referred for evaluation of abnormal cervical cytology: atypical squamous cells of undetermined significance (ASCUS); low-grade squamous intraepithelial lesion (LGSIL); high-grade squamous intraepithelial lesion (HGSIL); or squamous cell carcinoma (SCC) were evaluated by repeat pap smear, hybrid capture HPV DNA analysis and colposcopy. Colposcopic findings were recorded, and if appropriate, cervical biopsies were performed. Hybrid capture results were correlated with histologic and cytologic findings. Using histopathologic diagnosis as the reference standard, the sensitivity and positive predictive value of pap smear and high risk HPV were calculated. The Kappa test was used to correlate colposcopic and histopathologic findings.

RESULTS

Repeat pap smears at the time of initial consultation demonstrated 25 patients with normal results, 39 with LGSIL, 30 with HGSIL, 1 SCC and 5 ASCUS. Seventy-eight patients underwent cervical biopsy. Colposcopic findings correlated significantly with histopathologic findings (p<0.0001). Forty-four percent of patients tested positive for HPV DNA: 40 patients with high risk HPV, three patients with low risk HPV, and one patient with both high risk and low risk HPV. Sixteen of 39 patients (41%) with LGSIL on pap smear tested positive for high risk HPV; 37% of patients in this group required cervical conization because cervical biopsies demonstrated moderate/severe dysplasia. The diagnosis of moderate/severe dysplasia significantly correlated with the presence of high risk HPV [OR 78.9 (8.31-389.30)]. There was no significant correlation between the HPV DNA signal strengths and the histologic grade of dysplasia. The sensitivity and the positive predictive value of pap smear alone in identifying moderate/severe dysplasia was 62% and 96%, respectively. The combination of HGSIL pap smears and high risk HPV increased the sensitivity but not the positive predictive value for the detection of moderate/severe dysplasia to 77.7% and 95%, respectively (P=NS).

CONCLUSIONS

Although in this setting, the use of hybrid capture DNA testing did not significantly improve the sensitivity or positive predictive value of the diagnosis of HGSIL cytology when compared to cytologically indicated plus colposcopically directed cervical biopsies in this population of women at high risk for the presence of disease, the combination of HGSIL pap smears and high-risk HPV did result in a clinically important increase in the diagnosis of moderate/severe dysplasia.