Validity of combined cytology and human papillomavirus (HPV) genotyping with adjuvant DNA-cytometry in routine cervical screening: results from 31031 women from the Bonn-region in West Germany

Our aim was to improve the accuracy of routine cervical screening by a risk-adapted multimodal protocol with special focus on possible reduction and prognostic assessment of false positive results. A cohort of 31031 women from the Bonn-region in West Germany, median age 36 years, were screened by cytology (conventional or liquid-based), followed by PCR-based HVP detection with genotyping and adjuvant DNA image cytometry, if indicated, in a sequential manner. The true prevalence of high-grade cervical intraepithelial neoplasia and carcinoma (>/=CIN2) was 0.32% in the population as projected from cervical biopsies of 123 women (0.4%), of whom 100 showed >/=CIN2. Sensitivity of the cytology screening program at PapIIID/HSIL threshold for detecting histologically confirmed >/=CIN2 cases was 81%, with specificity, positive predictive value (PPV) and negative predictive value (NPV) of 99, 20.9 and 99.9%, respectively. Of 38 women receiving the complete screening protocol, all the 31 >/=CIN2 cases were correctly detected by cytology alone, 30 by positive high-risk HPV genotype and 30 by aneuploid DNA profile. The combination of the three methods resulted in an up to 6.9% increase in PPV for >/=CIN2 at practically unchanged detection rate with the additional benefit of being able to predict the probable outcome of CIN1 lesions detected as false positives with any single test. Multimodal cervical screening might permit identification of those women with low-grade squamous intraepithelial lesions likely to progress at an earlier and curable stage of disease and lengthen the screening interval in those with transient minor lesions caused by productive HPV infection.