Presentation Type: Speech
Abstract: Introduction: Breast conserving surgery and external radiotherapy have been the cornerstones of breast cancer treatment globally. Intraoperative Radiotherapy (IORT) is a new modality in breast cancer treatment. The first studies on IORT have been reported in ELIOT and TARGIT A. The ELIOT Study was done with an Electron device on 1200 cases, and the TARGIT-A study was done by an X-Ray device on more than 3000 patients.
Material and methods: This study was done on 445 female breast cancer patients who received IORT by Electron device in Iran from 9/2013 to 9/2016. The patients received boost or radical doses, according to age, tumor pathology, lymph node and hormone receptor status. Radical IORT 21 Gy was used for patients older than 50 years, tumors less than 3 centimeters and negative lymph nodes according to ASTRO protocol. Patients between 40-50 years, tumors smaller than 2 centimeters, Invasive Ductal Carcinoma, negative lymph nodes, positive hormone receptor and no lymphovascular invasion, were eligible for radical IORT. The same protocol of radical IORT was used for patients with Ductal Carcinoma in Situ. Other patients in this study received 12 Gy electron as a boost dose.
Results: The mean age was 51.4 years; mean size of tumor was 2.3 centimeters. Percentage of cases who had negative lymph nodes was 57 and the mean number of positive lymph nodes was 1.68. In addition Lymphovascular invasion was seen in 38.2% of cases. The hormone receptor status of cases is as follows: Estrogen Receptor positive 82.2%, Progesterone Receptor positive 81.2%, Her2 positive 13.6%, and 64.3% had Ki67 over 14% indicating poor prognosis. In total 67.3% of case received boost dose and 32.7% radical dose of IORT. Early complications of IORT (e.g. seruma, infection, hematoma) occurred in 14.4%; and late complications (e.g. fibrosis, fat necrosis) in 2.9% of cases. Local recurrence happened in 0.9% and distant metastases in 1.1% of cases. The death rate during this follow up period was 0.4%.
Conclusion: The mean follow up time of this study was 20 months and we acknowledge that this is not sufficient since we need to follow up the patients for 5 years; nonetheless we are reporting the early results for this period with very few recurrence rate.