Abstract P4-15-03: Patterns of relapse following re-irradiation of the breast using partial breast brachytherapy (PBB)

Abstract

Abstract Purpose: This study is undertaken to evaluate the patterns of relapse among patients with a prior history of irradiation where the RT field included the breast, and who received re-irradiation using PBB for a localized second cancer event in the breast using partial breast. Materials and Methods: Twenty-seven patients were enrolled in an IRB approved study. Nineteen patients had prior history of breast cancer treated with lumpectomy and external beam therapy (ERT), and 8 patients had prior history of mantle RT. All patients underwent lumpectomy with negative margins and received a median dose of 45Gy PBB. The median time interval between the primary breast cancer diagnosis and the second cancer event in the ipsilateral breast is 94-months (range 28-months to 211-months). The median time between mantle RT and the breast cancer is 245 months. Results: At a median follow up of 73 months following lumpectomy and PBB 14.8 % (4/27) patients developed a local recurrence and were salvaged by mastectomy. The 5-year Kaplan Meier local disease-free survival and mastectomy-free survival is 100% and 81%, respectively. Remarkably, one third of patients with prior history of mantle RT developed third primary cancers (pancreas, lung and renal). All patients with the third primary cancers died free of any relapse from the breast cancer. None of the patients with prior history of breast cancer developed a second malignancy, and 3/21 developed distant metastases. Conclusions: In appropriately selected patients with prior history of lumpectomy and ERT for breast cancer we observed a high rate of local control and freedom from mastectomy. Patterns of relapse among patients with prior mantle RT suggest that breast conservation and PBB was appropriate for treating early stage disease. Breast conservation therapy did not have a detrimental effect on breast cancer specific outcome and eventual patient survival. Patients motivated for breast conservation may have an alternative to mastectomy at initial diagnosis. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-15-03.