Do mammographic features of locally recurrent breast cancer mimic those of the original tumour?

The aim of this study was to compare the mammographic features of locally recurrent breast cancer after conservative surgery with those of the original tumour. The mammograms of 31 patients who developed local recurrence were reviewed retrospectively. In 7 out of 9 (78%) patients where the original tumour was primarily a soft tissue abnormality (mass or architectural distortion) the recurrence also appeared as a soft tissue abnormality. In 5 out of 6 (83%) patients where the original tumour appeared as microcalcification the recurrence was also detected owing to the presence of new microcalcification (P < 0.05). Fifteen of the 25 patients (60%) with a mammogram suspicious of malignancy at the time of the original tumour also had radiological signs of recurrence. However, in all six patients where the original tumour was not visible mammographically the recurrence was also mammographically occult (P < 0.05). Locally recurrent breast cancer tends to have similar radiological appearances to those of the original tumour and this may aid radiologists in assessing mammography following breast conserving surgery. Where the primary breast cancer is occult on mammography, mammographic surveillance after breast conservation is unlikely to identify local recurrence.