ESTRO 36 Abstract Book

S630 ESTRO 36 2017 _______________________________________________________________________________________________

Hence, TB delineation is sum total of information from surgical notes, surgical clips, postoperative changes on radiation therapy (RT) planning scans, histopathology report and some calculated guess work. Objective: To determine utility of preoperative CT scan in TB delineation after BCS. Material and Methods This pilot study was conducted in Department of Radiation Oncology, Max Hospital, Delhi, India, on 21 breast cancer patients in whom prior to BCS, preoperative CT scan was done in treatment position on a flat couch, in CT simulator. A radio opaque fiducial was also placed at the centre of palpable lump. After BCS & chemotherapy (if any), RT planning CT scan was taken with similar set up as pre-operative CT scan. Both the scans were co-registered using non-deformable registration on Eclipse Version 10.0. TB was contoured on RT planning CT using surgical clips (TB1) and also on preoperative CT scan (TB2). Tumor bed on all RT planning scans were scored for Cavity Visualization Score (CVS). Relative shift in position of TB on both the scans was compared in all three [lateral (RL), cranio caudal (CC) and Antero-posterior (AP)] directions. Results In our patients, median age was 59 years (Range 42-71). Median of maximum tumor size was 2.5 cm (Range 1.0- 5.0). All patients underwent BCS with oncolplastic reconstruction. Median time between preoperative and RT planning scan was 4.6 months. CVS 1 and 5 was observed in 6 patients each and rest patients were having CVS 2, 3 or 4. Mean preoperative, postoperative and combined tumor volume were 10.9cc, 10.9cc and 23.4cc respectively. On evaluating relative positions of tumor bed on pre-operative vs RT planning scan, mean (± SD) RL shift was 2.8 cm (± 1.8), which was larger than for the other directions (CC shift 1.2 cm, SD ± 0.9; AP shift 1.6 cm, SD ± 1.1). When relative shifts of TB were co-related with tumor location, RL & CC shifts were more in outer quadrant tumors (p=0.0005 & 0.016 respectively), while in AP direction, p value (0.26) was not statistically Preoperative CT scan in treatment position is an additional useful tool in calculated guess work of TB delineation and helps in improving the accuracy of target volume delineation for TB boost. EP-1170 Hypofractionated radiotherapy for ductal carcinoma in situ using VMAT: acute toxicity and cosmesis F. De Rose 1 , A. Fogliata 1 , D. Franceschini 1 , C. Iftode 1 , A.M. Ascolese 1 , T. Comito 1 , L. Di Brina 1 , A. Tozzi 1 , C. Franzese 1 , E. Clerici 1 , G.R. D'Agostino 1 , P. Navarria 1 , F. Lobefalo 1 , M. Scorsetti 1 1 Istituto Clinico Humanitas, Radiotherapy and Radiosurgery, Rozzano Milan, Italy Purpose or Objective To evaluate acute skin toxicity and cosmesis in DCIS patients enrolled in a phase II trial of hypofractionated breast irradiation using VMAT. Material and Methods Patients treated for DCIS with breast-conserving surgery were eligible for a phase II trial of hypofractionated breast irradiation. All DCIS patients underwent VMAT technique to irradiate the whole breast with a total dose of 40.5 Gy delivered in 15 fractions over 3 weeks, without tumor bed boost. Acute skin toxicities were recorded according to RTOG scoring criteria, and late skin toxicities according to CTCAE v4.0. Cosmetic outcomes were assessed as excellent/good or fair/poor according to the Harvard scale. Results From May 2013 to March 2016, 123 DCIS patients accrued. Median age was 56 year (range 30-82 years). The median follow up was 18 months (range 6-63). Most of the tumors significant. Conclusion

were moderately differentiated (51 %) with a no comedo subtype with necrosis DCIS histology (73 %). Sentinel node biopsy was performed in 57 patients (46,3 %). Concomitant hormonal therapy was administered in 16 %. At the end of RT treatment skin toxicity profile was G1 in 56% of the patients, G2 in 14%, no patients presented G3 toxicity. At six months of follow up skin toxicity was G1 in 25% of patients, no G2-G3 cases; cosmetic outcome was good/excellent in 92% of patients. At one year skin toxicity was G1 in 24% of patients; no G2-G3 toxicity was recorded; cosmetic outcome was good/excellent in 94% of patients. After an early evaluation of clinical outcomes we have found 3 cases of local relapse. Conclusion These results evidence that hypofractionated radiotherapy using VMAT is a safe option for DCIS. A longer follow up is needed to assess clinical outcomes and late toxicity. EP-1171 Thermography and association to high-grade radiation dermatitis: a prospective trial on 64 patients. N. Leduc 1 , V. Atallah 2 , A. Petit 1 , S. Belhomme 1 , P. Sargos 1 , V. Vinh-Hung 3 1 Institut Bergonié, Radiation Oncology, Bordeaux, France 2 University Hospital of Bordeaux, Radiation Oncology, Bordeaux, France 3 University Hospital of Martinique, Radiation Oncology, Fort-de-France, France Purpose or Objective Thermography has been successfully used for non-invasive imaging of various diseases. Radiation-induced dermatitis characterizes by an inflammatory state and sensation of heat. We designed a prospective, observational, single- center study to acquire data about the bi-dimensional evolution of temperature in the treated breast during the course of radiotherapy, seek possible association with the occurrence of dermatitis and eventually inquire about the predictive value of temperature increase over the future occurrence of radiation dermatitis. Material and Methods All consecutive patients treated for localized breast cancer at the University Hospital of Martinique between May and September 2016 were eligible for inclusion. Included patients were examined weekly by trained investigators for the occurrence of radiation dermatitis. A high-resolution frontal image of torso was taken every week. Treated and contralateral areas were compared. Results 64 patients were included. All demonstrated an increase in local temperature over the course of treatment. The occurrence of high grade radiation-induced dermatitis was significantly associated to a higher increase of local average temperature (1.88 vs. 1.15 °C, p < 0.0001). Preliminary results analyzing the predictive value of prior temperature elevation over subsequent occurrence of high-grade radiation dermatitis showed highest sensitivity and specificity of respectively 75% and 69% with a temperature threshold of 1.4°C. Figure 1 demonstrates typical thermal images of torso at 0 and 50 Gy. Temperature is plotted in °C.