Population-based frequency assessment of HPV-induced lesions in patients with borderline Pap tests in the Emilia-Romagna Region: the PATER study

Background: The PATER study assessed the frequency of high-risk (HR) and low-risk (LR) human papillomavirus (HPV) in HPV-induced lesions in patients with borderline cytology. Methods: This retrospective observational cohort study was designed to evaluate ASCUS patients detected through a local cervical cancer screening programme and referred to the Department of Gynaecology and Obstetrics at the S. Orsola-Malpighi University Hospital in Bologna, in the period between January 2000 and December 2007. Results: In 1047 patients aged 38.4 ± 9.6 years (range 23-65 years), 34.8% (n = 364) was positive for HR- or LR-HPV DNA. The mean age of women with HPV infection was significantly lower compared with the negative group (36.8 ± 9.4 versus 39.3 ± 9.6 years; p < 0.001). Overall, 357 (34.1%) women had cervical lesions: 279 (26.6%) had CIN1, 18 (1.7%) CIN2, and 60 (5.7%) CIN3+. HR-HPV genotype was detected in 83.3%, and 91.5% of patients with CIN2 and CIN3+ respectively. Among the 124 CIN1 HPV-positive women, 8.9% harboured LR-HPV genotypes, 80.6% HR-HPV and 10.5% a combination of HR- and LR-HPV. HPV-6 and 11 accounted for 19.4% of all HPV-positive CIN1 lesions. Conclusion: Our study suggest that: in ASCUS patients over 40 years there is a low risk of positivity for HPV infection; the HPV DNA testing in patients with CIN3+ and a mean age close to 40 years is highly sensitive (98.3%) and acceptably specific (75.5%); the frequency of LR-HPV (alone or in combination with HR) in ASCUS cytology is not negligible. A tetravalent-based HPV vaccination alongside the screening programme would provide considerable clinical, organizational, and economic benefits.