Trends in delayed breast cancer diagnosis after recall at screening mammography.

OBJECTIVES: To determine the extent and characteristics of delay in breast cancer diagnosis in women recalled at screening mammography. METHODS: We included a consecutive series of 817,656 screens of women who received biennial screening mammography in a Dutch breast cancer screening region between 1997 and 2016. During at least 3.5 years follow-up, radiological reports and biopsy reports were collected of all recalled women. The inclusion period was divided into four cohorts of four years each. We determined the number of screen-detected cancers and their characteristics, and assessed the proportion of recalled women who experienced a diagnostic delay of at least 4 months in breast cancer confirmation. RESULTS: The proportion of recalled women who experienced diagnostic delay decreased from 7.5 % in 1997-2001 (47/623) to 3.0 % in 2012-2016 (67/2223, P < 0.001). The proportion of women with a delay of at least two years increased from 27.7 % (13/47) in 1997-2001 to 75.7 % (53/70) in 2012-2016 (P < 0.001). Cancers with a diagnostic delay > 2 years were more frequently invasive (P = 0.009) than cancers with a diagnostic delay of 4-24 months. The most frequent cause of diagnostic delays was incorrect radiological classifications by clinical radiologists (55.2 % overall) after recall. CONCLUSIONS: The proportion of recalled women with a delayed breast cancer diagnosis has more than halved during two decades of screening mammography. Delays in breast cancer diagnosis are characterized by longer delay intervals, although the proportion of these delays among all screen-detected cancers has not increased. Preventing longer delays in breast cancer confirmation may help improve breast cancer survival.