Evidence of interval cancer proportional incidence and review from mammography screening programs in Italy.

PURPOSE To summarize the existing evidence on the proportional incidence and review of interval cancers, as reported by Italian screening programs. MATERIAL AND METHODS Literature search of published reports on: a) proportional incidence, determined according to breast cancers expected in the absence of screening and estimated on the basis of patients/year at risk and age-specific incidence; and b) review of screening mammograms preceding interval cancers. Results were compared with European Commission recommended standards. RESULTS Evidence on proportional incidence or review of interval cancers was reported by 37 and 24 local health unit programs, respectively. Compared to European Commission standards, 94% and 87% of programs complied at first interval cancers survey with recommended standards for proportional incidence or screening error rate at review, respectively. Two programs initially below acceptable standards reached satisfactory results at repeat evaluation over time. CONCLUSIONS Although they are a minority (20%) of all local health unit programs, which suggests a possible selection bias, Italian surveys reporting data on the proportional incidence or review of interval cancers show an overall good performance. Interval cancer survey appears feasible in any program and should become a routine procedure within the national quality control system.