Mammographic features of local recurrence in women who have undergone breast-conserving therapy for ductal carcinoma in situ

OBJECTIVE. This study was undertaken to evaluate the mammographic features of local recurrence in women who have undergone breast-conserving therapy for ductal carcinoma in situ (DCIS). MATERIALS AND METHODS. Retrospective review revealed 162 women with DCIS treated with breast-conserving therapy from 1978 to 1990 for whom follow-up data were available. Subsequent to therapy, 33 (20%) patients had a pathologically proven car; cinema in the treated breast. Mammograms at the time of local recurrence were available for 20 patients. We reviewed mammograms, clinical charts, and histopathologic findings in these 20 patients. For 14 of 20 patients, we also reviewed mammograms obtained at the time of the original DCIS. RESULTS. The median interval from diagnosis of the original DCIS to local recurrence was 26 months (range, 6-168 months). Recurrences were detected solely by mammography in 17 (85%) of 20 patients, by mammography and physical examination in two (10%), and solely by physical examination in one (5%), Eighteen (90%) local recurrences contained calcifications and eighteen (90%) involved the tumorectomy quadrant. When we compared available mammographic findings of the original DCIS and the local recurrence, we found the mammographic pattern and calcification morphology to be the same in 11 (79%) of 14 DCIS and nine (82%) of 11 DCIS, respectively, Histopathologic analysis of recurrences found DCIS in 13 (65%) of 20 patients and DCIS and infiltrating carcinoma in the remaining seven (35%) patients. Of 13 pure DCIS recurrences, 12 (92%) were detected solely by mammography. CONCLUSION. In our study, local recurrence after breast-conserving therapy for DCIS invariably contained DCIS; 35% of recurrences also contained invasive carcinoma, The most common mammographic pattern of local recurrence was calcifications in the tumorectomy quadrant that were morphologically similar to the original DCIS. These findings suggest that many of these local recurrences reflect failure to eradicate the primary DCIS. Mammography achieved high sensitivity in revealing these lesions: 85% of local recurrences and 92% of recurrences that were pure DCIS were detected solely by mammography.