Phase I/II trial of partial breast irradiation (PBI) with various concurrent chemotherapy regimens.

1128 Background: Potential benefits of concurrent chemo-radiation include: shorter duration of treatment, smaller interval between surgery and adjuvant therapies, and synergistic effects. We have previously shown that PBI with concurrent dose dense doxorubicin and cyclophosphamide (ddAC) is well tolerated (Zellars JCO 2009). We performed a follow-up feasibility trial of PBI delivered concurrently with other various chemotherapy regimens. Methods: Women with T1-2, N0-1 breast cancer s/p lumpectomy with ≥2 mm margins were eligible. Chemotherapy regimen was at the discretion of the medical oncologist (Table). PBI (40.5 Gy in 15 daily 2.7 Gy fractions) was delivered within the first 2 cycles of chemotherapy. Primary endpoints were hematologic and non-hematologic toxicities graded according to Common Terminology Criteria for Adverse Events manual (v. 3.0). Results: Thirty-four patients enrolled with median f/u of 19.2 mos. (4.0 - 38.6). Mean tumor size was 1.8 cm (+/- 0.7 cm), 71% pN0, 68% HR +, 18% Her2 +. Al...