Interval cancer review in the Leicestershire symptomatic breast service

Interval cancer review is an important part of quality assurance within the NHSBSP. No equivalent assessment is performed within the symptomatic service. We attempted to apply a similar review to the symptomatic work performed at our centre.

All patients referred to our centre with a breast symptom are seen in 'one-stop' triple assessment clinics. We identified, and reviewed the imaging of, patients diagnosed with in situ or invasive carcinoma at our unit during 2007 who had undergone breast imaging via the symptomatic service within 3 years prior to diagnosis.

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.

'Interval cancers' within the symptomatic population are a small but heterogeneous group. We discuss the details and present a pictorial review of the interesting cases.