Objectives: Human papillomavirus (HPV) infection is a sexually transmitted disease (STD) and the single most important etiological agent of cervical cancer. In parallel with the increase of STDs and because of the lack of any organized cancer screening in the new independent states of the former Soviet Union, the incidence and mortality rates of cervical cancer are rapidly rising. This is the first report from an ongoing European Commission-funded (INCO-Copernicus Program) cross-sectional and cohort study (focused on the key issues of this major health problem in the new independent states) analyzing the performance of the HPV DNA (Hybrid Capture II) test as a potential screening tool for cervical cancer in these countries.
Materials and methods: A series of 3,175 women (screening, gynecological, or STD patients) from six clinics in Russia, Belarus, and Latvia received routine cytology and HPV testing with Hybrid Capture II (HCII). All women with HPV-positive results or abnormalities in cytology were subjected to colposcopy and biopsy. The sensitivity, specificity, receiver operating characteristics, as well as positive (PPV) and negative predicting values (NPV), were determined for HCII and quality-controlled cytology in detecting significant pathology (cervical intraepithelial neoplasia [CIN] 3 and cancer).
Results: Significant pathology was strongly associated with high-grade cytology (odds ratio [OR] = 8.5; 95% confidence interval [CI] = 4.1-17.8; chi-square, p < .0001). Pap smear cytology detected high-grade lesions with a sensitivity of 64.0% (44.8-83.2), specificity of 89.1% (84.5-93.7), PPV of 44.4% (28.8-61.0), and NPV of 94.8% (91.2-98.4). Of the 3,086 samples analyzed by HCII, 33.0% were positive for oncogenic HPV types, with a wide variation (from 23% to 45%) between the three patient groups (p < .0001). The presence of high-grade cytology was significantly associated with HCII positivity at all cutoff levels (OR = 14.4; 95% CI = 8.4-24.5; chi-square, p < .0001; 1 pg/mL threshold). In the receiver operating characteristics curve, the HCII cutoff point most closely balancing sensitivity (83.1%) and specificity (75.6%) was 2 pg/mL. The presence of high-grade histology was associated with HCII positivity (cutoff 1 pg/mL; OR = 4.8; 95% CI = 0.7-34.2;p = .047). At the cutoff (1 pg/mL), sensitivity of the HCII test was 96.6% (90.0-100), specificity was 15.9% (10.6-21.2), PPV was 15.1% (9.9-20.3), and NPV was 96.8% (90.3-100). Changing the cutoff significantly affected sensitivity at 20 pg/mL and NPV at 500 pg/mL.
Conclusions: HCII assay is a sensitive tool in detecting significant pathology, but less specific than the Pap test. A negative HCII test practically precludes high-grade CIN (NPV, >95%). Because the performance characteristics of the HCII test depend on the prevalence of HPV and CIN in the study population, the cost-benefit issues in different settings will be the limiting factor for the application of this test as a screening tool.