ESTRO 2021 Abstract Book

S1003

ESTRO 2021

prescribed on this volume. The remaining volume of PTV receives the full prescription dose (25 Gy in 5 fractions). During treatment, we performed a cone beam CT before and after each fraction. Results From August 2016 to October 2020, we have treated 10 patients. The mean age was 61.52 years. 3 women and 7 men. Of 9/10 patients, we had histological confirmation of malignancy. Only 1 of the patients was previously treated with surgery (margin status R2), offering SBRT to local recurrence at 10 months. 8/10 patients received FOLFIRINOX prior to SBRT, with a mean number of cycles of 8.68 (5-16). SIB-SIP was used in 9/10 patients. The minimum dose prescribed on PTV was 25 Gy / 5 fractions. The maximum prescription dose administered on PTV SIB was 40, 33, 32, and 24 Gy in 1, 7, 1, and 1 patient, respectively. The mean volume of the PTV 25Gy and PTV SIP was 88.77 cc and 29.16 cc, respectively. The mean total duration of the treatment was 11 calendar days. The treatment time for each fraction was less than 10 minutes in all cases. 2/10 patients did not complete the proposed treatment due to problems not related to toxicity or progression. At the time of analysis, 6/10 patients had already died. The mean OS from diagnosis to death or last follow-up is 18.59 months (range 9.53-27.4 months). The mean OS since the end of SBRT treatment is 9.4 months. 6/10 patients had suffered local relapse (within PTV) with a mean local progression-free interval of 5.4 months (range 1.2-19.17 months). Conclusion In our experience, SIB-SIP SBRT in LAPC is feaseble and shows similar results in terms of local control and overall survival to published data. Ongoing and future clinical trials will offer more information about the controversial role of SBRT in this field. PO-1210 Is SBRT safe in carcinoma pancreas having duodenal infiltration? R. Engineer 1 , J. Poddar 1 , A. Anoop 1 , V. Ostwal 2 , A. Ramaswamy 2 , R. Mhatre 1 , S. Shrikhande 1 1 Tata Memorial Centre, Radiation Oncology, Mumbai, India; 2 Tata Memorial Centre, Medical Oncology, Mumbai, India Purpose or Objective Carcinoma pancreas with duodenal infiltration is usually not treated with SBRT, due to risk of increased complications like gastrointestinal bleed, ulceration and fistula formation. A retrospective analysis of patients, who were treated with SBRT, was done, to study the incidence of the above said complications Materials and Methods An IRB approved retrospective analysis of 98 patients of carcinoma pancreas treated with SBRT during 2017 to 2020 was done. Of these 98 patients, 12 patients had duodenal infiltration, on duodenoscopy and Contrast enhanced CT (pancreatic protocol) at baseline. Patients with adenocarcinoma of head/body of pancreas, a median follow up of 6 months after SBRT, and mucosal duodenal invasion on pre-treatment duodenoscopy and tri-phasic CECT (pancreatic protocol), were included. Dose painted SBRT was delivered. Dose of 25-30 gray/5- 6 fractions to tumor abutting the duodenum and up to 42Gray/ 5-6 fractions to tumor/vessel interface was delivered. The analysis evaluated, whether patients with duodenal invasion had increased incidence of grade ≥ 3(G3) gastrointestinal toxicity(GI), ulceration, bleeding or fistula formation. Results Of 12 patients with duodenal invasion, 10 had tumours of the head and 2 had in the body of pancreas. 6 patients were Locally advanced and 6 were borderline resectable pancreatic cancer. All patients received 4 to 6 cycles of NACT (FOLFIRINOX n=10, and Gem- Nab Paclitaxel n=3) before SBRT. All received a dose of 25-30 Gray/5-6fractions to the duodenum- tumour interface and 42 Gray/5-6 fractions to tumour vessel interface, without any intra-fraction or inter-fraction complications. 2(15%) underwent surgery. One patient had pathological complete response and is post treatment 3 years and is still on follow up. None of the patients developed grade 3 GI toxicity, GI bleed, ulcer or fistula. Five patients had grade 1, two patients had grade 2, and five patients had no GI toxicity. There was no association between duodenal invasion and the incidence of G3 toxicity, ulceration and bleeding. Median overall survival was 10 months (range 4-30 months) and median follow up from conclusion of SBRT was 7 months (range 2-26 months) Conclusion Duodenal invasion, prior to SBRT did not increase GI bleeding duodenal ulceration, or fistula risk. Our data suggests that pancreatic adenocarcinoma patients with duodenal invasion, can be treated with SBRT using a dose-painting approach. PO-1211 Intraluminal brachytherapy boost in esophageal cancer: A single institute retrospective analysis. N. Bathija 1 , H. Rathod 1 , S. Kunikullaya 1 , A. Parikh 1 , M. Mehta 1 , S. Patel 1 , V. Shivhare 1 , S. Rath 1 , V. Modi 1 , H. Jain 1 , D. Anand 1 , K. Ratanchandani 1 1 The Gujarat Cancer and Research Institute, Radiation Oncology, AHMEDABAD, India Purpose or Objective Palliation of dysphagia remains a challenge in advanced esophageal cancer. The addition of intraluminal brachytherapy (ILBT) to external beam radiotherapy (EBRT) has shown significant improvement in dysphagia relief and symptom scores. This retrospective audit analyses the dysphagia free duration and toxicity associated with addition of ILBT boost to palliative EBRT. Materials and Methods The medical records of 63 patients with advanced/metastatic esophageal cancer were screened from January 2015 to April 2018. All patients received 30 Gy in 10 fractions palliative radiotherapy followed by two fractions of 8 Gy each of ILBT one week apart, Patients were assessed for the symptom scores of dysphagia, odynophagia, regurgitation, and chest pain and weight was recorded periodically (EORTC-QLQOG25).Primary end point was dysphagia free survival .