Phase II Study of Intra-Operative Electron Irradiation and External Beam Irradiation After Lumpectomy in Patients With T1N0M0 and T2N0M0 Breast Cancer

IOERT is given to the tumor bed. Applicator selection should allow treatment of the tumor bed plus 1-2 cm margin. The surgical incision may need to be enlarged slightly to allow the placement of the appropriate applicator. The use of more than 1 treatment field is discouraged. In order to encompass the entire tumor bed in 1 treatment field, it may be necessary to suture the mammary parenchyma loosely so that the lateral margins of the tumor bed are brought into apposition. Electron energy used for the treatment. If the tumor bed can be flattened and encompassed by an applicator, 6 MeV electron is recommended. Use of bolus material may be considered to increase the surface dose. If the mammary parenchyma has been brought into apposition by sutures, a higher electron energy may be necessary to allow adequate dose coverage to a depth of 1.0-2.0 cm into the tumor bed. The dose of IOERT is 1000 cGy, prescribed to the 90% isodose line.