Consequences of digital mammography in population-based breast cancer screening: initial changes and long-term impact on referral rates

Abstract

Objectives: To investigate the referral pattern after the transition to full-field digital mammography (FFDM) in a population-based breast cancer screening programme.

Methods: Preceding the nationwide digitalisation of the Dutch screening programme, an FFDM feasibility study was conducted. Detection and referral rates for FFDM and screen-film mammography (SFM) were compared for first and subsequent screens. Furthermore, radiological characteristics of referrals in digital screening were assessed.

Results: A total of 312,414 screening mammograms were performed (43,913 digital and 268,501 conventional), with 4,473 consecutive referrals (966 following FFDM). Initially the FFDM referral rate peaked, and many false-positive results were noted as a consequence of pseudolesions and increased detection of (benign) microcalcifications. A higher overall referral rate was observed in FFDM screening in both first and subsequent examinations (p < .001), with a significant increase in cancer detection (p = .010).

Conclusion: As a result of initial inexperience with digital screening images implementing FFDM in a population-based breast cancer screening programme may lead to a strong, but temporary increase in referral. Dedicated training in digital screening for radiographers and screening radiologists is therefore recommended. Referral rates decrease and stabilise (learning curve effect) at a higher level than in conventional screening, yet with significantly enhanced cancer detection.

Fig. 1

Time course of referral in a FFDM and b SFM screening for first (○) and subsequent (♦) screening examinations

Fig. 2

Radiological characteristics of referred lesions in digital mammography (rates per 1,000)

Fig. 3

Results of a referred masses and b referred microcalcifications (rates per 1,000)

Fig. 4

Pseudolesion seen with high contrast resolution in FFDM. a Prior screening mammogram (SFM), b screening mammogram followed by referral (FFDM), c mammogram in subsequent clinical assessment (FFDM)