[INTRAOPERATIVE RADIOTHERAPY (IORT) IN EARLY BREAST CANCER - 500 PATIENTS, ONE CENTER'S EXPERIENCE].

AIMS: To present our Institute's experience with intraoperative radiotherapy in this selected population by collecting and analyzing clinical data, including long-term follow-up. BACKGROUND: Breast-conserving therapy is the standard treatment for early-stage breast cancer. The treatment includes tumor resection and a whole breast irradiation. Intraoperative radiotherapy is a single dose of irradiation given to the tumor bed immediately after it is removed. This treatment is suitable for a selected population of patients with early stage breast cancer, which constitutes about 20% of all breast cancer patients and is supposed to replace the standard whole breast radiation treatment. METHODS: Between the years 2006-2017, 737 women with early breast cancer were treated in Carmel Medical Center with intraoperative radiotherapy. We herein report the results of the first 500 patients who were treated until 2015. RESULTS: In 13.8% of the patients, additional breast treatment was recommended due to poor pathological characteristics of the disease in final pathological examination. During a median follow-up period of 74 months (1-136), recurrence was observed in 22 patients (4.4%), and in 7 patients (1.4%) recurrence was observed in regional lymph nodes; 13 patients (2.6%) developed metastatic disease. Risk factors for regional recurrence were identified: tumor size greater than 2 cm, lack of adjuvant therapy and poor genetic profile of the disease. CONCLUSIONS: Intraoperative radiotherapy is feasible and may offer an alternative to the standard whole breast radiotherapy, in low risk early breast cancer patients. The patients should be selected according to known risk factors.

[Intraoperative radiotherapy (IORT) in early breast cancer].

BACKGROUND: Breast-conservation therapy is widely accepted as an effective treatment option for patients with early stage carcinoma of the breast. The proportion of patients with recurrence after receiving partial breast irradiation is the same as that seen in patients treated with whole breast irradiation. Therefore, the necessity of whole breast irradiation has been questioned, and partial breast irradiation has emerged as a reasonable alternative. METHODS: Since 2006, 468 women with early breast cancer (age > 60 years, T1, infiltrative duct carcinoma and with no clinical or sonographic suspicion of involved axillary lymph nodes) were treated in the Carmel Medical Center with intraoperative radiotherapy, using the INTRABEAM System giving 20 Gy at the tumor bed. We report the cohort of the first 100 patients who have had a follow up period of more than 3 years. RESULTS: The median age was 70 years (range 56-87 years). Twenty four patients had mild to moderate local complications, while nine patients experienced major local complications. Eighteen patients had metastatic involvement of the axillary lymph nodes, and in 16 of them, only one node was involved. Five patients had additional local therapy (one patient underwent mastectomy and four patients received whole breast irradiation). During the follow up period, four ipsilateral breast failures were observed: two new primary tumors (by location and histology) and two local recurrences. CONCLUSIONS: Intraoperative radiotherapy using the INTRABEAM system is feasible and may offer an alternative to whole breast radiotherapy, in low risk early breast cancer patients with a low rate of local recurrence and morbidity. Longer follow up is required in order to evaluate long term results and late toxicity.