Problems, solutions, and perspectives in the evaluation of interval cancers in Italian mammography screening programmes: a position paper from the Italian group for mammography screening (GISMa).

In this position paper, a self-convened team of experts from the Italian Group for Mammography Screening (Gruppo italiano screening mammografico, GISMa) pointed out the problems that increasingly hamper the feasibility and validity of the estimate of the proportional incidence of interval breast cancer (IBC) in Italy, suggested potential solutions and an agenda for research, and proposed that the question of the sensitivity of mammography be viewed in a larger perspective, with a greater attention to radiological review activities and breast radiology quality assurance programmes. The main problems are as follows: the coverage of cancer registration is incomplete; the robustness of using the pre-screening incidence rates as underlying rates decreases with time since the start of screening; the intermediate mammograms performed for early detection purposes may cause an overrepresentation of IBCs; the classification of many borderline screening histories is prone to subjectivity; and, finally, the composition of cohorts of women with negative screening results is uncertain, because several mammography reports are neither clearly negative nor clearly positive, and because of the limitations and instability of the electronic mammography records. Several possibilities can be considered to cope with these issues: standard methods for using the hospital discharge records in the identification of IBCs should be established; for the calculation of regional estimates of the underlying incidence, a suitable mathematical model should be identified; the definition of IBC according to the 2008 GISMa guidelines needs to be updated, especially with respect to in situ cancers and to invasive cancers with borderline screening histories; a closer adherence to standard screening protocols, with a simplified patient management, would make it easier to objectively identify IBCs; alternative methods for estimating the sensitivity of mammography should be taken into consideration; and, finally, analysis could be restricted to the absolute incidence rate of IBC, which would make comparison of the risk between neighbouring populations possible. Epidemiologists must extend their attention to the prevention of the risk of IBC and the implementation of breast radiology quality assurance practices. Epidemiologists and radiologists can share common objectives: it is necessary to promote the idea that the availability of a registry-based series of IBCs is not a prerequisite for their radiological review; radiological review of breast cancers greater than 20mm in size detected at second and subsequent screens, that are potential substitutes for IBCs, needs radiological and epidemiological validation studies; the advent of digital mammography brings about the possibility to create libraries of mammograms accessible online, which enables the conduct of large studies of the diagnostic variability of radiologists; and, finally, epidemiologists and radiologists have the responsibility to monitor the effects that a loss of cumulative professional experience in screening centres, due to the imminent retirement of a substantial proportion of healthcare workforce, could cause on their performance.

Proportional incidence of interval colorectal cancer in a large population-based faecal immunochemical test screening programme.

BACKGROUND: The European guidelines for quality assurance in colorectal cancer (CRC) screening recommend that interval cancer rate be expressed as a proportion of background incidence rate. AIM: To determine the crude and adjusted proportional incidence of interval CRC in an Italian regional two-yearly faecal immunochemical test (FIT) screening programme. METHODS: The programme (year of implementation, 2005) is targeted at over 1,000,000 people aged 50-69 years. The test is a one-sample OC-Sensor (Eiken Chemical Co., Tokyo, Japan). The study covered one-third of the regional area. Excerpts of 434,295 eligible negative FIT records dated 2005-2012 from 193,193 subjects were retrieved from the regional CRC screening data warehouse. By 31 December 2013, the cohort accumulated 198,302 man-years and 235,370 woman-years. Interval CRCs were identified by record-linkage with the local population-based cancer registry. Their number was divided by the expected number, estimated with age-period-cohort models, to obtain the proportional incidence. RESULTS: The proportional incidence of interval CRC for men and women was, respectively, 0.06 (95% confidence interval (CI), 0.04-0.09) and 0.17 (95% CI, 0.13-0.23) in the first interval year, and 0.21 (95% CI, 0.16-0.26) and 0.28 (95% CI, 0.22-0.36) in the second year. CONCLUSIONS: The results were acceptable and in line with previous studies.

Advanced breast cancer rates in the epoch of service screening: The 400,000 women cohort study from Italy.

BACKGROUND: The objective of this study was to evaluate if mammography screening attendance is associated with a reduction in late-stage breast cancer incidence. METHODS: The cohort included over 400,000 Italian women who were first invited to participate in regional screening programmes during the 1990s and were followed for breast cancer incidence for 13 years. We obtained individual data on their exposure to screening and correlated this with total and stage-specific breast cancer incidence. Socio-economic status and pre-screening incidence data were used to assess the presence of self-selection bias. RESULTS: Overall, screening attendance was associated with a 10% excess risk of in situ and invasive breast cancer (IRR = 1.10; 95% confidence interval (CI): 1.06-1.14), which dropped to 5% for invasive cancers only (IRR = 1.05; 95% CI: 1.01-1.09). There were significant reductions among attenders for specific cancer stages; we observed a 39% reduction for T2 or larger (IRR = 0.61; 95% CI: 0.57-0.66), 19% for node positives (IRR = 0.81; 95% CI: 0.76-0.86) and 28% for stage II and higher (IRR = 0.72; 95% CI: 0.68-0.76). Our data suggest that the presence of self-selection bias is limited and, overall, invited women experienced a 17% reduction of advanced cancers compared with pre-screening rates. CONCLUSIONS: Comparing attenders' and non-attenders' stage-specific breast cancer incidence, we have estimated that screening attendance is associated with a reduction of nearly 30% for stages II+.