ESTRO 36 Abstract Book

S356 ESTRO 36 _______________________________________________________________________________________________

Purpose or Objective Pancreatic carcinoma is projected to become the 2^ leading cause of cancer mortality by 2030. At diagnosis, 30% of patients (pts) present with LAPC involving adjacent structures such as blood vessels, not usually removed because of risk of postoperative complications. Patients with LAPC have an intermediate prognosis between resectable and metastatic pts (median OS ranging from 5 to 11 months). LAPC cause significant pain, obstruction, and other morbidity due to direct extension of the primary tumor. Currently, a treatment option for LAPC is radio- chemotherapy (RCT). SBRT is one emerging technique for treatment of LAPC, used by specialized centers to deliver a higher biologically effective dose of precisely targeted radiation in a short course of therapy. Conformity and rapid dose fall-off associated with SBRT offer the potential for dose escalation. We retrospectively review the experience of 5 different centers treating LAPC with SBRT. Material and Methods We included 41 pts with LAPC, undergoing SBRT +/- chemotherapy (CT) with multiagent CT regimens. Exclusion criteria were metastatic disease and radical surgical treatment. Only palliative surgery was admitted. Median dose and median fractionation dose for SBRT were 25 Gy (range: 4-45) and 6 Gy (range: 4-22), respectively. Toxicity was evaluated by CTCAE.4 scale. Overall survival (OS) was estimated and compared by Kaplan-Meier and log-rank methods, respectively. Results We analyzed 41 pts (M/F: 21/20; median age: 71, range: 36-89). Median, 6 months, 1-year, and 2-year OS were: 15 months (range 13.5-16.4), 87.6%, 73.9%, 20.1%, respectively. At univariate analysis a better prognosis was recorded for pts with tumor located at the tail (p= 0.046), with a histologic grade 2 tumor (p<0.001), treated with adjuvant CT (p=0.036). There was a trend for improved OS in pts with cT3 tumor stage (p=0.085), and in pts treated with biliary stent (p=0.066). Nodal stage was not significantly related to OS. Incidence of gastrointestinal (GI) G1-G2 acute toxicity was 40%. Only one case of G3 GI acute toxicity (4%) and only one of G3 GI late toxicity (4.5%) were registered.

PO-0681 SBRT VS standard chemoradiation in locally advanced pancreatic cancer (LAPC): a case-control study A. Arcelli 1 , F. Bertini 1 , A.G. Morganti 1 , A. Guido 1 , L. Fuccio 2 , F. Deodato 3 , S. Cilla 4 , F. Dalla Torre 3 , V. Scotti 5 , E.M. Rosetto 6 , I. Djan 7 , S. Parisi 8 , G.C. Mattiucci 9 , V. Valentini 9 , M. Fiore 10 , P. Bonomo 11 , A. Bacigalupo 12 , R.M. Niespolo 13 , P. Gabriele 14 , G. Macchia 3 1 University of Bologna, Radiation Oncology Center- Department of Experimental- Diagnostic and Specialty Medicine - DIMES, Bologna, Italy 2 University of Bologna, Department of Medical and Surgical Sciences - DIMEC, Bologna, Italy 3 Fondazione di Ricerca e Cura “Giovanni Paolo II”, Radiotherapy Unit, Campobasso, Italy 4 Fondazione di Ricerca e Cura “Giovanni Paolo II”, Medical Physic Unit, Campobasso, Italy 5 Radiosurgery Center Malzoni, Radiosurgery Center, Agropoli, Italy 6 Ospedale Belcolle, Radiotherapy Unit, Viterbo, Italy 7 Medical Faculty- University of Novi Sad, Institute of Oncology Vojvodina- Sremska Kamenica, Serbia, Serbia 8 Ospedale Casa Sollievo della Sofferenza San Giovanni Rotondo, Radiotherapy Unit, Foggia, Italy 9 Policlinico Universitario “A. Gemelli”- Università Cattolica del Sacro Cuore, Department of Radiotherapy, Rome, Italy 10 Università Campus Biomedico, Department of Radiotherapy, Rome, Italy 11 Azienda Ospedaliero Universitaria Careggi AOUC, Department of Radiotherapy, Firenze, Italy 12 IRCCS AOU San Martino– IST, Department of Radiotherapy, Genova, Italy 13 Azienda Ospedaliera San Gerardo, Radiotherapy Unit, Monza, Italy 14 Fondazione del Piemonte per l'Oncologia FPO- IRCCS Candiolo, Department of Radiotherapy, Torino, Italy Purpose or Objective In the last decades a treatment option for LAPC has been represented by chemoradiation (CRT), however SBRT is considered an emerging option for these patients (pts). Unfortunately, comparison between these two treatment techniques, in terms of toxicity and pts outcome, are lacking. Therefore, aim of this multicentric study is to compare toxicity and outcome between two cohorts of pts treated with SBRT or CRT. Material and Methods A case-control study was performed. Forty-two patients were enrolled (M/F: 25/17; median age: 68.5; range: 36- 89). Pts in the two groups were matched according to: age

Conclusion Fractionated SBRT +/- CT results in tolerable acute and minimal late GI toxicity and warrants OS comparable to current standard treatment (RCT). Future studies should incorporate SBRT with more aggressive multiagent CT to optimize pts outcomes.