The adverse implications of the transition from film to digital mammography for performing surveillance in patients with a history of breast cancer or significant risk factors for the disease

Abstract

The transition from screen-film to digital mammography at Peter MacCallum Cancer Centre was investigated, considering the impact on patient management and resource utilization. A retrospective comparison of the imaging outcomes of the last year of screen-film and the first year of digital mammography was performed. The study group of 692 patients, all with a history or a significant risk factor of breast cancer, underwent a surveillance mammogram in both periods, enabling serial comparison of imaging outcomes on the same patient. Overall 92 patients required a total of 125 further investigations after their film mammogram due to a mammographic abnormality while 130 underwent a total of 202 additional investigations after their digital mammogram. This is a significant increase in the number of patients further investigated (Fisher's exact test P = 0.005). However, the positive predictive value of further investigation finding a tumor after digital mammography was not significantly higher than that of film mammography (7.4 vs 6.5%, Fisher's exact test P = 0.57). There was a 44% increase in the cost of additional investigations during the first year of digital mammography compared to the previous year and an associated increase in hospital visits for patients. For patients undergoing annual surveillance mammography at Peter MacCallum Cancer Centre, the transition from film to digital mammography was found to be associated with an increase in both the number of additional investigations performed and in the number of hospital visits. The findings of this study should be considered when conversions from film to digital mammography are planned, specifically in terms of cost allocations and the burden on patient services in radiology and outpatient departments.