Zorzi M, Giorgi Rossi P; Gruppo di lavoro sugli Indicatori dello screening con test HPV primario

Epidemiol Prev. 2017 Jan-Feb;41(1):1-32 doi: 10.19191/EP17.1S1.P001.001.



Following scientific evidence produced in numerous studies, as well as national and international guidelines, organized cervical cancer screening programs in Italy have gradually introduced the HPV test as primary screening test, replacing cytology. As public health interventions, screening programs must ensure equity, improvement in quality of life, and adequate information for the population involved with regards to benefits and possible risks; therefore, it is essential for quality to be constantly checked at every phase of the project.The Italian Cervical Screening Group (Gruppo Italiano per lo Screening Cervicale, GISCi) has written a handbook for the calculation and interpretation of cervical screening program monitoring indicators that take into account the new protocol based on primary HPV test with cytology triage.

Based on the European guidelines and Italian recommendations on primary HPVbased screening, the working group, which includes professionals from all the fields involved in cervical screening, identified the essential points needed to monitor the screening process, the accuracy of individual tests, and early outcomes, defining a specific indicator for each aspect. The indicators were grouped as follows: baseline indicators, indicators for test repeat after one year, cumulative indicators, and waiting times. For every indicator, the source of data, calculation formula, any standards or critical thresholds, and interpretation were defined. The standards are based on the results of NTCC trials or Italian pilot studies.

The main indicators proposed for the organization are the following: number of invitations, compliance with first invitation, with one-year test repeat and with colposcopy; for test and process accuracy, a cohort approach was utilised, where indicators are based on women who must be followed for at least one year, so as to integrate the results obtained after the first HPV test with the outcome of the test's repetition after one year; the proposed indicators are positive HPV test, positive triage cytology, and positive predictive value of the referral to colposcopy at first and test repeat, and detection rate at first and test repeat.

Monitoring the new screening protocol, with cytology triage and one-year test repeat, is more complex, as it imposes a higher number of indicators and requires a cohort approach, which increases the delay before data are obtained.