Between January 2005 and December 2007, 11,796 ultrasounds and 17,530 mammograms were performed within the symptomatic service. Of the total 681 cancers diagnosed in 2007, 34 of these were 'interval cancers' to the symptomatic service. The interval since discharge was ≤12 months in 9 patients, 13 to 24 months in 18 and 25 to 36 months in 7.
Fourteen cancers were felt to be true intervals, six mammographically occult, and five suspicious. Nine were unclassifiable. Of the unclassifiable cases, one had missing imaging and eight did not have mammo-graphy at prior attendance. Only four of these were symptomatic in the same area as their cancer was later diagnosed.