Delayed diagnosis of breast cancer in women recalled for suspicious screening mammography

PurposeTo determine the frequency, pathology and causes of a delay in cancer diagnosis in women recalled for suspicious screening mammography.MethodsWe included all 290,943 screening mammograms of women aged 50–75 years, who underwent biennial screening mammography between 1st January 1995 and 1st January 2006. During a follow-up period of at least 2 years, clinical data, breast imaging reports, biopsy results and breast surgery reports were collected of all 3513 women with a positive screening result. Tumour stages of breast cancers with a diagnostic delay (defined as breast cancer confirmation more than 3 months following a positive mammography screen) were compared with those of cancers diagnosed within 3 months following referral and with interval cancers.ResultsA diagnostic delay occurred in 97 (6.5%) of 1503 screen-detected cancers. These 97 false-negative assessments comprised significantly more ductal cancers in situ (26.8%) than did cancers with an adequate assessment after recall (15.5%, p = 0.004) or interval cancers (3.7%, p < 0.001). Compared with interval cancers, cancers with a false-negative assessment had a more favourable tumour size (T1a–c, 87.3% versus T1a–c, 46.4%; p < 0.001) and showed significantly fewer cases with axillary lymph node metastases (22.5% versus 48.2%; p < 0.001). Between hospitals having performed the workup of at least 500 referred women each, the percentage of women with a false-negative assessment varied from 5.0% to 9.1% (p = 0.03). In these hospitals, improper classification of lesions at diagnostic mammography comprised 64.4% of false-negative assessments.ConclusionWe found that 6.5% of recalled women experienced a delay in breast cancer diagnosis, with significant performance variations between hospitals.