Technical and clinical breast cancer screening performance indicators for computed radiography versus direct digital radiography.

OBJECTIVES: To compare technical and clinical screening performance parameters between computed radiography (CR) and direct digital radiography (DR) systems. METHODS: The number of women screened with CR was 73,008 and with DR 116,945. Technical and patient dose survey data of 25 CR and 37 DR systems were available. Technical performance was expressed by threshold thickness values at the mean glandular dose (MGD) level of routine practice. Clinical indicators included recall rate (RR), cancer detection rate (CDR), percentage of ductal carcinoma in situ (DCIS), percentage of cancers with T-scores smaller than 1 cm and positive predictive value (PPV). RESULTS: Contrast threshold values for the 0.1-mm gold disk were 1.44 µm (SD 0.13 µm) for CR and 1.20 µm (SD 0.13 µm for DR). MGD was 2.16 mGy (SD 0.36 mGy) and 1.35 mGy (SD 0.32 mGy) for CR and DR respectively. We obtained for CR, respectively DR, the following results: RR in the first round of 5.48 % versus 5.61 %; RR in subsequent rounds of 2.52 % versus 2.65 %; CDR of 0.52 % versus 0.53 %; DCIS of 0.08 % versus 0.11 %; a rate of cancers with T-scores smaller than 1 cm of 0.11 % versus 0.11 %; PPV of 18.45 % versus 18.64 %; none of them was significantly different. CONCLUSION: Our screening indicators are reassuring for the use of CR and DR, with CR operating at 60 % higher MGD. KEY POINTS: • Breast cancer screening can employ both computed (CR) and direct digital radiography (DR). • Screening performance parameters for CR and DR technology are not significantly different. • Screening parameters are in accordance with European Guidelines. • Radiation doses employed for CR are generally 60 % greater than for DR.

Does digital mammography in a decentralized breast cancer screening program lead to screening performance parameters comparable with film-screen mammography?

OBJECTIVE: To evaluate if the screening performance parameters of digital mammography (DM) in a decentralized screening organization were comparable with film-screen mammography (FSM). METHODS: A nationwide screening program was launched in 2001, and since 2005 screening with DM has been allowed. Firstly, the parameters of the three regional screening units (RSUs) that first switched to DM (11,355 women) were compared with the FSM period of the same three RSUs (23,325 women). Secondly, they were compared with the results of the whole central breast unit (CBU). RESULTS: The recall rate (RR) of the DM group in the initial round was 2.64% [2.40% for FSM (p = 0.43)] and in the subsequent round 1.20% [1.58% for FSM (p = 0.03)]. The cancer detection rate (CDR) was 0.59% for DM and 0.64% for FSM (p = 0.56). The percentage of ductal carcinoma in situ was 0.07% for DM and 0.16% for FSM (p = 0.02). The positive predictive value was high in the subsequent rounds (DM 48.00%, FSM 45.93%) and lower in the initial round (DM 24.05%, FSM 24.86%). Compared with the results of the whole CBU, DM showed no significant difference. CONCLUSION: DM can be introduced in a decentralized screening organization with a high CDR without increasing the RR.