ESTRO 36 Abstract Book

S626 ESTRO 36 2017 _______________________________________________________________________________________________

Although the series is not homogeneus, there was no significant difference in the incidence of acute or late toxicity in pts that underwent or not to chemotherapy. Conclusion In our seriesHRT is well tollerated with a good toxicity profile and a good cosmetic result. There is no clear evidence that chemotherapy has an impact to acute or late skin toxicity after HRT. In our analysis we can not evaluate the role that have sequential boost in causing late toxicity. EP-1162 Non surgical breast conserving treatment using a new radiosensitizer T. Shimbo 1 , K. Yoshida 1 , N. Yoshikawa 1 , H. Yoshioka 1 , M. Nakata 1 , Y. Narumi 1 , T. Komori 1 , H. Matsutani 1 , T. Hamada 1 , Y. Uesugi 2 1 Osaka Medical College, Radiation Oncology, Osaka, Japan 2 Kansai University of Welfare Sciences, Medical treatment for health, Kashihara, Japan Purpose or Objective The purpose of this clinical study was to clarify a non- surgical breast-conserving therapy (BCT) using a new radiosensitizing agent for the early stage breast cancer patients who rejected surgery. This new radiosensitizer, named KORTUC (Kochi Oxydol-Radiation Therapy for Unresectabe Carcinomas) containing 0.5% hydrogen peroxide and 0.83% sodium hyaluronate has been developed for intra-tumoral injection in various tumors. Hydrogen peroxide is the only agent known to be capable of inactivating antioxidative enzymes and producing oxygen when applied topically to tumor tissues. By the addition of sodium hyaluronate, which makes the solution more viscous and slows the degradation of hydrogen peroxide, allowing long-acting radiosensitization of the local tumor tissue. Material and Methods A total of five early stage breast cancer patients (stage I, 2; stage II, 3) who rejected surgery were enrolled in the KORTUC trial after providing a fully informed consent. The mean age of the patients was 67.5 years (range; 38- 80). The tumor size was 24.6mm (range; 14-47). A maximum of 6 mL of the radiosensitizar agent was injected into breast tumor tissue twice a week under ultrasonographic guidance. We used hypo-fractionated radiotherapy with conventional linear accelerator. Forty- four Gy in 16 fractions were irradiated for whole breast and ipsilateral axillary region with tangential field, and an additional electron boost of 9Gy in 3fractions were delivered for primary tumor site. Results Treatment was well tolerated with minimal adverse effects in all patients. No patients showed any significant complications other than mild dermatitis. Three patients with estrogen receptor-positive tumors were also started on hormone therapy following KORTUC treatment. All patients showed clinically complete response (cCR). The mean duration of a follow-up was 15.6 months (5/23/26/27/44 months), respectively. All patients were alive with no evidence of disease at present. The mean period taken to confirm cCR on the breast contrast- enhanced CT, MRI or PET-CT was approximately 8.2 months. Cosmetically, all patients evaluated as having an excellent appearance in their ipsilateral breast. Conclusion Non-surgical BCT (KORTUC-BCT) can be performed safely and effectively for patients with early stage breast cancer. KORTUC-BCT can be one of the treatment options to breast cancer patients who rejected surgery. EP-1163 A Prospective Evaluation of Lumpectomy Cavity Volume Changes During Whole Breast Radiotherapy

Fig 2: Disease free survival according to TNM staging system Conclusion Many authors are pointing the lack of uniformity and discriminating power of the T4 subcategory of TNM classification. The subgroup of T4 small tumors have a better OS and DFS in our retrospective study. We hope that adding the T4s subcategory to the TNM classification, will encourage providing more data about its prognosis. EP-1161 Hypofracionated Radiation Therapy in Breast Cancer: retrospective analysis of late toxicity P. Ferrazza 1 , F. De Renzi 1 , T. Iannone 1 1 Ospedale Civile San Martino, Radioterapia, Belluno, Italy Purpose or Objective Various randomised trials have established the role of hypofracionated radiotherapy (HRT) in breast cancer. The aim of our retrospective analysis is to evaluate late toxicy and cosmetic results in patients treated with hypofracionated radiotherapy after breast conserving surgery followed or not by chemoterapy. Material and Methods We included in this analysis patients (pts) treated with breast conserving surgery and HRT with a follow-up of at least 4 years. From january 2007 to september 2012, 239 pts with early breast cancer (TNM stage pTis pT1-2 and N0- N1mic) were treated with adjuvant hypofractionated radiation therapy. 40 pts underwent anthracycline-taxane based chemotherapy befor HRT, 161 pts received only hormone therapy and 38 pts received no other therapies. Total dose delivered to whole breast was 45.66 Gy/16 fx in 233 pts and 42.4 Gy/16 fx in only 6 pts. 36 pts received a sequential boost on tumor bed (10 Gy/5 fx). Late toxicity was recorded according RTOG/EORTC Late Radiation Morbidity Scoring Schema. Results Median age was 61 years (range 36-86 years). 38/239 had DCIS, 158/239 pts had stage I disease and 43/239 had stage II disease. Median follow-up was 61 months. Most common acute toxicity was skin grade 1 (56%) and grade 2 (36.8%). Only 1 pts presented grade 3 skin toxicity. 112 pts present grade 1 skin late toxicity (58 pts grade 1 edema, 38 pts grade 1 pigmentation changes , 7 pts telangiectasia , 9 pts grade 1 atrophy and 6 pts both edema and pigmentation change ). No >grade 3 events were reported. Only 3 grade 3 fibrosis occurred. The cosmetic results were excellent in 76% pts, good in 19% pts and fair in 5% pts. No pulmonary or cardiac toxicity was observed.