ESTRO 36 Abstract Book

S631 ESTRO 36 _______________________________________________________________________________________________

Material and Methods We had undertaken a retrospective study of T4 tumors treated by radiotherapy in the departments of radiation oncology in the Farhat Hached University Hospital and Medical Centre Ibn Khaldoun Results 250 patients classified as T4 tumors by our Committee for Gynecologic Oncology were treated in our departments between January 1995 and December 2013. From these 250 patients, 79 were classified as T4d breast tumors and 171 non inflammatory breast cancer. From these, 11 cases the primary tumor size is unknown, 20 patients had small tumors under 3 cm at presentation, and 140 patients had tumors of 3cm in size or larger. Seventeen were classified as T4a, 127 as T4b and 27 as T4c. 148 patients had underwent neoadjuvant chemotherapy, mastectomy, and adjuvant radiotherapy. The median age was 50 years (ranging from 23 to 78). The median size at presentation was 5 cm. the median follow- up period was 42 months (ranging from 0 to 231). The 5 years Disease free survival was 89% for small tumors versus 59% for non-inflammatory larger tumors and 48% for inflammatory breast cancer. With statistically significant difference p = 0.037 (fig 1). The overall survival was 89% versus 70% for non- inflammatory larger tumors and 62% for inflammatory breast (p = 0.28). These finding support the fact that small T4 tumors had a different behavior and better prognosis than other locally advanced tumors, thus it should be considered as a distinct entity. Indeed we propose that these tumors should be classified T4”s” ('s” as small). Although the actual T4 TNM subgrouping is lacking of discriminative power, actually we did not find a significant difference comparing the DFS (p = 0.34) or OS (p = 0.7) according to the T4 TNM subgrouping (fig 2).

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.

Fig 1: Disease free survival of the T4 s subgroup compared with larger T4 non inflammatory breast cancer and T4d