Digital mammography versus film-screen mammography: technical, clinical and economic assessments
Report in Brief
Digital Mammography versus Film-Screen Mammography: Technical, Clinical and Economic Assessments October 2002
Digital mammography systems for breast cancer detection.
Mammography is an X-ray examination of the breast used to detect breast cancer. The current standard, film-screen mammography (FSM), has several inherent limitations on image quality. Digital mammography (DM) was developed as a convenient alternative that is expected to improve the quality of breast imaging and reduce the radiation dose required. DM involves the digital capture of images through two different technologies:
Digital radiography mammography (DR-M) is a direct system; X-ray information is directly converted into a digital image. Total annualized capital and operating costs for a single DR-M may be as much as $249,000 more than FSM.
Computed radiography mammography (CR-M) is an indirect system; X-ray information is captured on a detector plate, from which a digital image is created. Total annualized capital and operating costs for CR-M are equivalent to FSM.
Breast cancer is the most common cancer to affect women. It is the second leading cause of cancer death in Canadian women after lung cancer. Each year in Canada as estimated 19,500 women are diagnosed with breast cancer and 5,500 die from it.
Is DM more expensive than FSM? Is DM more clinically effective than FSM?
To compare the technical, clinical and potential costs of DM and FSM within the context of the Canadian health care system based on a systematic review of published and unpublished studies.
An electronic search with no language restrictions was conducted of published and conference literature. The results were screened using different filters for the technology review, the clinical review and the economic analysis. Irrelevant reports were excluded based on title and abstracts. Full reports were then evaluated and relevant reports were accepted for final inclusion. Thus, the technical review was based on 37 relevant articles; the clinical review on 7; and the economic analysis on 17.
DR-M has significantly higher annualized costs than either FSM or CR-M. Potential clinical benefits (improved diagnostic accuracy, shorter examination time, lower radiation dose) for patients, institutions and payers have not been demonstrated in a clinical setting. The ability to detect cancer is comparable for DR-M and FSM. (There is not sufficient data on clinical effectiveness of CR-M). Assuming that DR-M and CR-M are, at best, clinically equivalent to FSM, the minimum-cost system is preferred; therefore, conventional FSM is preferable to DM at this time.
This summary is based on a comprehensive
health technology assessment report available from CCOHTA’s web site (www.ccohta.ca):
Ho C, Hailey D, Warburton R, MacGregor J, Pisano E, Joyce J. Digital
mammography versus film-screen mammography: technical, clinical and economic
Canadian Coordinating Office For Health Technology Assessment (CCOHTA)
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