Team Reading (Peer Review) of Suspicious/Positive Slides for Continuous Quality Improvement in Cervical-Vaginal Cytology: A Comparison between Methods and Indicators.

AIM: In 2013, the Local Health Unit Roma 2 ex C screening laboratory introduced a new set of indicators for quality assurance. We compare 2 sets of indicators based on routine multiple readings (peer review) for their ability to identify problems in single-reader accuracy. METHODS: All suspect slides were blindly reviewed by all the cytologists of the laboratory. The standard set of indicators includes interreader Cohen's kappa, positivity rate and atypical squamous cell of undetermined significance/squamous intraepithelial lesion (ASC-US/SIL) ratio. The new set included sensitivity for cervical intraepithelial neoplasia of grade 2 or worse (CIN2+), positive predictive value (PPV) and percentage of positive high-risk (HR)-HPV cases among ASC-US. In order to estimate sensitivity and PPV, we considered all women for whom there was a consensus of negative cytology, negative HR-HPV test, negative colposcopy or negative histology true negative. RESULTS: Kappa values ranged from 0.521 to 0.753, with narrow 95% confidence intervals (CIs). Positivity rate ranged from 73.9 to 85.7 and the ASC-US/SIL ratio from 0.61 to 0.81. Sensitivity for CIN2+ at the low-grade SIL threshold ranged from 85.8 to 94.2, PPV ranged from 14.8 to 19.4, and both had a broad 95% CI. Readers with low sensitivity did not show low kappa values. The percentage proportion of HR-HPV-positives (HR-HPV+) among ASC-US ranged from 39.9 to 43.8% with a narrow 95% CI. CONCLUSION: The proportion of HR-HPV+ among ASC-US cases is a powerful indicator to address in training.

Distribution of high and low risk HPV types by cytological status: a population based study from Italy.

BACKGROUND: HPV type distribution by cytological status represents useful information to predict the impact of mass vaccination on screening programs. METHODS: women aged from 25 to 64 who attended cervical cancer screening in five different Italian regions were tested for HPV infection with Hybrid Capture II (HCII) low and high risk probes. Women repeating Pap-test upon unsatisfactory or positive results, or as a post-treatment and post-colposcopy follow-up analysis, were excluded from our study. High risk (HR) HPV positive samples were typed using GP5+/GP6+ primed PCR, followed by Reverse Line Blot for 18 high/intermediate risk HPV types, while low risk (LR) HPV positive samples were tested with type specific primers for HPV6 and HPV11. RESULTS: 3410 women had a valid HCII and Pap-test. The prevalence of HR and LR infections was 7.0% and 3.6%, 29.1% and 13.7%, 68.1% and 31.9%, 60.0% and 0.0%, 65.0% and 12.0%, for negative, ASC-US, L-SIL, ASC-H and H-SIL cytology, respectively. The fraction of ASC-US+ cytology due to HPV 16 and 18 ranged from 11.2 (HPV 16/18 alone) to 15.4% (including HPV 16/18 in co-infection with other virus strains), and that due to HPV 6 and 11 ranged from 0.2% (HPV 6/11 alone) to 0.7% (including HPV 6/11 in co-infection with other LR virus strains). CONCLUSIONS: mass vaccination with bivalent or quadrivalent HPV vaccine would modestly impact on prevalence of abnormal Pap-test in screening.