Management of Ipsilateral Breast Tumor Recurrence Following Breast Conservation Surgery for Ductal Carcinoma In Situ: A Data-Poor Zone.

Abstract

Breast conserving surgery (BCS) is well established for the management of ductal carcinoma in situ (DCIS), but neither randomized trials nor guidelines address management of ipsilateral breast tumor recurrence (IBTR) after BCS for DCIS. We identified women treated with BCS for DCIS who developed IBTR as a first event. Between those treated with mastectomy versus re-BCS, we compare the clinicopathologic characteristics, the use of adjuvant radiotherapy (RT) both upfront ("primary RT") and post IBTR ("secondary RT"), of tamoxifen, the rate of third events (local, regional, distant), and both breast cancer specific (BCSS) and overall survival (OS). Of 3001 women treated with BCS for DCIS (1978-2010), 383 developed an IBTR as a first event (1983-2023) and were treated by mastectomy (51%) versus re-BCS (49%). Compared with re-BCS, mastectomy patients at initial treatment were higher grade (74% versus 59%, p = 0.004), with more frequent primary RT (61% versus 21%, p < 0.001). Third local events were more frequent for re-BCS than mastectomy (16% versus 3%, p = 0.001), but there were no differences in breast cancer specific or overall survival. For isolated IBTR following BCS for DCIS and treated by mastectomy versus re-BCS (1) mastectomy was associated with less favorable initial pathology and more frequent use of primary RT, (2) re- recurrence was more frequent with re-BCS, and (3) BCSS and OS were comparable. Our data suggest a wider role for re-BCS and further study of the relationship between secondary RT and the rate of third breast events.