Partial breast irradiation with electron beam for patients with breast cancer submitted to conservative surgery.
Authors: Maia MA , Mourao Netto M , Maciel MS , Salvajoli JV , Pellizzon AC 
Published: December 2010

Abstract #5146

Introduction: conservative surgery is the standard procedure for initial breast cancer, followed by radiation therapy. Follow up after this approach has shown that about 90% of local recurrence occurs at the same quadrant or close to the tumor bed as well as studies of pathology. Based on the experience of Milan we have started a study protocol of intraoperative electron beam radiation (IORT), in september,2005.Purpose: to evaluate the feasibility, acute complications and cosmetic results of partial breast radiation therapy with electron beam, in patients submitted to conservative surgery and sentinel node dissection.Elegibity criteria: T&lt; or = 3 cm, clinically N0,no EIC,free surgical margins,unilateral tumo.Method: from sep/2005 to may/2008 we have evaluated 75 patients. All patients were submitted to conservative surgery at the Department of Radiation Therapy, in a surgical room near the Linear Accelerator. After removal of the tumor and histopathological analysis ( tumor size, surgical margins and sentinel nodal status), the surgeon places the plaque (made of lead and aluminium) to protect the chest wall and closes the tumor bed; the radiation oncologist measures the depth of the tumor bed to choose the electron beam energy, and puts the cone in place. The patient then is taken to the Linac room and we proceed to the irradiation. The dose is 21 Gy, isodose of 90%. After that we return to the surgical room and the surgical procedure is finished.Demographic caracteristics of the patients:mean age 58 years,breast side right 32(42%) left breast 43(58%),race white 66(88%) not white 9(12%) Results Staging – tumor size varied from 0.3 to 2.5 cm at histopatologic analisys, nodal status was N0 -63(84%), Nmic – 8 (10%) and N1–4(6%), histologic grade was GI–26(33%), GII -27(35%) and G III -22(32%)All patients were treated at a Linac, using an electron beam cone of 57 mm of intern diameter; 3 different cone angles were used according to the position of the tumor in the breast – degree 0 – 18 (24%), degree 15 – 34(45%), degree 30 – 23(31%); beam energy varied according to the depth of the breast tissue: 6 MeV – 35(47%), MeV – 35(47%),12 MeV – 4(5%),15 Mev – 1(1%).Systemic therapy 39(52%) patients had chemotherapy, 50(67%) hormonytherapy, 18(24%), none and 7(9%) are to decide ( still in chemo).We observed acute complications in 6(9%) patients such as seroma and local infection, clinically solved.Cosmetic results were bad in 2(2%) patient, fair in 10(12%), good in 32(43%) and excellent in 3 (43%). As for now two patients developed axillary metastasis 13 and 28 months after IORT, and were treated with axillary dissection.Conclusion: this is a quite feasible method for partial breast irradiation, with satisfactory results in terms of acute complications and cosmetic results. For local control and late complications we still have to wait more time and the reports of open trials. Meanwhile, it should be emphasized that these patients should only be treated in a study protocol.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5146.