• Rachel Farber, Nehmat Houssami, Kevin McGeechan, Alexandra L Barratt, and Katy Jl Bell.
• Sydney School of Public Health, the University of Sydney, Sydney, NSW.
• Med. J. Aust. 2025 Feb 3; 222 (2): 829082-90.

ObjectivesTo assess the impact of the transition from film to digital mammography in the Australian national breast cancer screening program.Study DesignRetrospective linked population health data analysis (New South Wales Central Cancer Registry, BreastScreen NSW); interrupted time series analysis.SettingNew South Wales, 2002-2016.ParticipantsWomen aged 40 years or older with breast cancer diagnosed during 2002-2017 who had been screened by BreastScreen NSW and for whom complete follow-up information until the end of the recommended re-screening interval was available.InterventionTransition from film to digital mammography; 2009 defined as transition year (digital mammography becomes dominant screening modality).Main Outcome MeasuresPopulation rates of screen-detected cancer, interval cancer, recalls, and false positive findings.ResultsThe study cohort comprised 967 573 women; of the 2 741 555 screens, 1 535 184 used film mammography (2002-2010) and 1 206 371 used digital mammography (2006-2016). The screen-detected cancer rate was 4.86 (95% confidence interval [CI], 4.75-4.97) cases per 1000 screens with film mammography and 6.11 (95% CI, 5.97-6.24) cases per 1000 screens with digital mammography (unadjusted difference, 1.24 [95% CI, 1.06-1.41] cases per 1000 screens). The interval cancer rate was 2.56 (95% CI, 2.48-2.64) cases per 1000 screens with film mammography and 2.84 (95% CI, 2.75-2.94) cases per 1000 screens with digital mammography (unadjusted difference, 0.27 [95% CI, 0.15-0.40] cases per 1000 screens). With the transition to digital mammography, the screen-detected cancer rate increased by 0.07 per 1000 screens, the sum of the decline in the invasive cancer rate (-0.21 cases per 1000 screens) and the rise in the ductal carcinoma in situ detection rate (0.28 cases per 1000 screens); during 2009-2015, it increased by 0.18 cases per 1000 screens per year. With the transition to digital mammography, the interval cancer rate increased by 0.75 cases per 1000 screens (invasive cancer: by 0.69 cases per 1000 screens); during 2009-2015, it declined by 0.13 cases per 1000 screens per year. The recall rate increased by 8.02 per 1000 screens and the false positive rate by 7.16 per 1000 screens following the transition; both rates subsequently declined to pre-transition levels.ConclusionsThe increased screen-detected cancer rate following the transition to digital mammography was not accompanied by a reduction in interval cancer detection rates.© 2025 The Author(s). Medical Journal of Australia published by John Wiley & Sons Australia, Ltd on behalf of AMPCo Pty Ltd.

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