Decreasing incidence of late‐stage breast cancer after the introduction of organized mammography screening in Italy

Abstract

the IMPACT Working Group BACKGROUND: After the introduction of a mammography screening program, the incidence of late-stage breast cancer is expected to decrease. The objective of the current study was to evaluate variations in the total incidence of breast cancer and in the incidence of breast cancers with a pathologic tumor (pT) classification of pT2 through pT4 after the introduction of mammography screening in 6 Italian administrative regions. METHODS: The study area included 700 municipalities, with a total population of 692,824 women ages 55 to 74 years, that were targeted by organized mammography screening between 1991 and 2005. The year screening started at the municipal level (year 1) was identified. The years of screening were numbered from 1 to 8. The ratio of the observed 2-year, agestandardized (Europe) incidence rate to the expected rate (the incidence rate ratio [IRR]) was calculated. Expected rates were estimated assuming that the incidence of breast cancer was stable and was equivalent to that in the last 3 years before year 1. RESULTS: The study was based on a total of 14,447 incident breast cancers, including 4036 pT2 through pT4 breast cancers. The total IRR was 1.35 (95% confidence interval, 1.03-1.41) in years 1 and 2, 1.16 (95% confidence interval, 1.10-1.21) in years 3 and 4, 1.14 (95% confidence interval, 1.08-1.20) in years 5 and 6, and 1.14 (95% confidence interval, 1.08-1.21) in years 7 and 8. The IRR for pT2 through pT4 breast cancers was 0.97 (95% confidence interval, 0.90-1.04) in years 1 and 2, 0.81 (95% confidence interval, 0.75-0.88) in years 3 and 4, 0.79 (95% confidence interval, 0.73-0.87) in years 5 and 6, and 0.71 (95% confidence interval, 0.64-0.79) in years 7 and 8. CONCLU-SIONS: A significant and stable decrease in the incidence of late-stage breast cancer was observed from the third year of screening onward, when the IRR varied between 0.81 and 0.71. Cancer 2013;119:2022-8.

The impact of mammography screening programmes on incidence of advanced breast cancer in Europe: a literature review

“…Only papers in English evaluating European programmes were reviewed. The search strategy was built using 7 key papers [9–15]. …”

“…1Expected effect of mammography service screening on the occurrence of advanced breast cancer, illustrated by Fig. 2, right panel, from Foca et al [15]. Ratios with 95% confidence intervals are illustrated between the observed and expected age-standardised incidence rates of breast cancer per 100,000 women according to a 2-year screening period (ages 55 to 74 years).…”

“…Because there is a latency for the effect of screening on ABCR to take place, at any point in time there are women (i.e., new quinquagenarians, new immigrants, and late attendees) with insufficient exposure time.The effect of screening on ABCR is underestimated, due to a disproportionate influence of prevalence screens.All studies3Pace of implementationPublic health screening programmes are implemented gradually, in a markedly stepwise fashion, since large populations are divided in distinct administrative units each targeted by an independent local plan of action.The effect of screening on ABCR is diluted. Until implementation is completed, there are women who are diagnosed with breast cancer before being invited, and who greatly contribute to ABCR.[8, 14, 15, 19, 29, 30, 32, 33, 36–39, 44]4Prevalence effectThe prevalence screen may be associated with a transient increase in ABCR [13]. During a stepwise implementation of the programme, when the time elapsed from the start is theoretically sufficient to see a decrease in ABCR, this is counteracted by an opposite effect due to newly enrolled women – especially if invitations increase over time.[8, 14, 15, 19, 29, 30, 32, 33, 36–39, 44]5Reference incidence (i)The reference (or underlying) incidence rate, with which to compare the rate observed after the introduction of screening, is not known with precision [49].…”

Detecting Germline PTEN Mutations Among At-Risk Patients With Cancer: An Age- and Sex-Specific Cost-Effectiveness Analysis

“…Using data from the largest prospective cohort of over 3000 CS and CS-like (defined as International Cowden Consortium criteria minus one) patients enrolled globally, 4,6,8 we created a decision model to simulate virtual clinical trials of different genetic screening strategies. The virtual trials included CS or CS-like patients who were older than 18 years and were referred to a clinical cancer genetics service.…”

Mammography, Martin Yaffe, and Me: Response and Appreciation

“…However, the discussion serves indirectly to bring out an important observation: that besides its traditionally accepted benefits in detection of earlier-stage disease, mammography also contributes to substantial reductions in the incidence of advanced or metastatic breast cancer [26][27][28][29][30][31][32][33][34] as was noted in a review of mammography screening rcts 35 . As Tabár's team demonstrated, trials reducing such advanced stage disease by at least 20% confer a 28% mortality reduction in screening-invited women, translating to an approximately 40% mortality reduction in screening-attendant women, compared with trials effecting a less than 10% reduction in advanced cancer, which were associated with no significant breast cancer mortality reduction 27,36 .…”