Breast conservation (BCT) for DCIS: A prospective study of how MRI impacts management (MGMT).

Abstract

546 Background: The optimal role of MRI in the MGMT of patients (pts) with DCIS remains undefined. We undertook this prospective study to evaluate the changes in MGMT that occur due to MRI findings. Methods: 100 pts <60 y.o. with core biopsy-proven DCIS (± microinvasion) were prospectively enrolled. After evaluation with mammography ± ultrasound (US), the operative plan was recorded. 86 were BCT candidates. Additional (addl) suspicious MRI findings and subsequent MGMT changes were then prospectively recorded. Significance was tested by chi squared. Results: See Table. Of 41 pts with addl MRI findings, 12 had BCT with 1 excision, 16 had attempted BCT but required subsequent TM or reexcision, 5 had TM as 1st operation a result of MRI, 17/41 (41%) had 1 operation. Of 45 pts with no additional MRI findings, 28 had BCT with 1 excision, 17 had attempted BCT but required TM or reexcision. 28 (62%) had 1 operation. Overall, MRI altered MGMT in 32/86 (37%) pts. Of these, 9 (10%) were spared an operation. To benefit these 9 pts, 28 procedures in 19 (22%) pts were generated. Among pts with no addl MRI findings, BCT was more likely to be successful (84% vs. 56%, p= 0.004) and to require 1 operation (62% vs. 29%, p= 0.002). Among pts with addl MRI findings, TM was more likely to be elected by pts (20% vs. 0%, p=0.002) or required (24% vs. 16%, p=0.3). Conclusions: MRI detects additional findings in 1/2 pts with core bx-proven DCIS, resulting in changes in MGMT for over 1/3 pts, reducing the number of operations in 10%. Additional MRI findings are associated with lower rate of successful BCT and higher required TM rate. For each pt for whom an operation is prevented, 2 pts have additional tests. Pts with additional MRI findings are more likely to elect TM. Pts with MGMT altered Additional procedures in 19 pts Pts saved an operation Pts electing mastectomy (TM) post-MRI Pts requiring TM Pts with successful BCT Pts with additional MRI findings (N = 41/86) 32/41 (78%) 28 9/41 (22%) 8/41 (20%) 10/41 (24%) 23/41 (56%) Separate lesions (N = 11) 11 16 0 2 1 8 Index lesion larger (N = 23) 15 5 7 3 8 12 Separate lesion and index lesion larger (N = 4) 3 3 1 2 1 1 MRI mass (N = 2) 2 2 1 0 0 2 Adenopathy (N = 1) 1 2 0 1 0 0 Pts without additional MRI findings (N = 45/86) 0 0 0 0 7/45 (16%) 38/45 (84%) Total (N = 86) 32/86 (37%) 28 9/86 (10%) 8/86 (9%) 17/86 (20%) 61/86 (71%) No significant financial relationships to disclose.