Abstract Book

S913

ESTRO 37

EP-1701 Phase I study of selective HT applied using magnetoliposomes in an 8-MHz capacitive heating device S. Kakinouchi 1 , T. Ohguri 1 , H. Imada 2 , K. Yahara 1 , K. Tomura 1 , S. Nakahara 1 , H. Narisada 2 , S. Ota 2 , Y. Korogi 1 , T. Kobayashi 3 1 University of Occupational and Environmental Health, Department of Radiology, Kitakyushu, Japan 2 Tobata Kyoritu Hospital, Cancer Therapy Center, Kitakyushu, Japan 3 Chubu University, College of Bioscience and Biotechnology, Kasugai, Japan Purpose or Objective A meta-analysis of combined treatment with radiotherapy (RT) and hyperthermia (HT) demonstrated that local tumor control rates were significantly better when tumors exhibited higher intratumor temperatures. Therefore, methods for elevating intratumor temperatures to therapeutic levels are needed. We developed magnetite particles with a cationic liposomal membrane, termed 'magnetite cationic liposomes” (MCLs), which have the ability to target cancer cells and heat them intracellularly. An 8-MHz capacitive heating device is widely used in Japan. The purpose of this study was to evaluate the temperature distribution in tumor tissue and the toxicity of a novel selective HT method using MCLs in the capacitive device. Material and Methods This prospective study was approved by the Institutional Review Board of the authors’ institution. Eligible patients with pathologically diagnosed malignant superficial tumors were identified. MCLs were injected into the superficial tumor, and 8-MHz radiofrequency capacitive heating was applied. One week before the injection of the MCLs, conventional HT without MCLs was applied as a reference. Before and after the injection of MCLs, computed tomography (CT) was performed to confirm the concentration of the MCLs in the tumor. Intratumor temperatures were measured using a four-point microthermocouple sensor. In all patients, RT was concurrently performed at a median total dose of 60 Gy and median daily dose of 2 Gy. Feasibility, including thermal parameters and toxicity of the selective HT, was prospectively evaluated. Results Five patients with superficial lymph node metastasis from various cancers were enrolled. In one patient, injection of the MCLs into the superficial tumor was unsuccessful because CT images showed that most of the MCLs had leaked out of the tumor; hence, selective HT could not be performed in that case. In the remaining 4 patients, the thermal parameters and toxicities were evaluated. The number of heating sessions performed using the MCLs ranged from 2 to 6 (median, 5). In the conventional HT method performed before the injection of MCLs, the median intratumor values of T25, T50, and T90 were 41.8°C, 40.6°C and 39.9°C, respectively, and the thermal dose of median CEM43T90 was 0.8 min. In the selective HT method with MCLs injection, the median intratumor values of T25, T50, and T90 were 43.5°C, 41.7°C, and 40.5°C, respectively, and the median CEM43T90 was 1.3 min in each heating session. Acute toxicity of grade 2 pharyngeal edema around the tumor was observed in one patient. Furthermore, late toxicity of grade 3 pharyngeal ulcer around the tumor was detected in one patient. An objective tumor response was noted in 2 (50%) of the 4 patients (CR, n = 1; PR, n = 1).

Conclusion The novel selective HT method using MCLs could improve the thermal parameters for intratumor temperatures. However, several issues, such as the technical difficulties of MCL injection and concerns regarding heat injury of surrounding normal tissues, were encountered. EP-1702 Stereotactic body radiotherapy for oligometastatic and oligoprogression patients C. De la Pinta Alonso 1 , C. Vallejo Ocaña 1 , R. Hernanz De Lucas 1 , M. Martín Martín 1 , E. Fernández-Lizarbe 1 , M. Martín Sánchez 1 , J. Domínguez Rullán 1 , T. Muñóz Migueláez 1 , F. López Campos 1 , A. Hervás Morón 1 , S. Sancho Garcia 1 1 Hospital Ramon y Cajal, Radiation Oncology, Madrid, Spain Purpose or Objective The aim of this study was evaluate toxicities and efficacy for oligometastatic and oligoprogression patients treated with SBRT in ur institution. Material and Methods Retrospectively, we analyzed patients treated with SBRT between 2013 and 2017. Oligometastatic (OM) patients were described as a state in which metastases are limited in number and site and characterized by unusual cancer biology and behavior. In this setting local therapy could have a potential curative role. Oligoprogression (OP) patients were described as those patients who progress after curative intent treatment. We analyzed acute and chronic toxicities, overall survival (OS), progression-free survival (PFS) and local control (LC). Results Fifty-nine metastatic patients treated for 60 lesions, 10p were treated in OM group and 49p were treated in OP group. The median age was 63 years old. The most common primary cancers were gastrointestinal neoplasm (n=20) and lung tumors (n=11). Median follow-up post- SBRT treatment was 13 months (range, 1-160months); 1- and 2-year PFS and LC was 62,5% and 60%, and 100% and 96,2%, respectively. The median OS was 62,75 months versus 35,96 months in the OM group and OP group (p=0,10). Radiation therapy was well tolerated, toxicity was grade 2 pain and fatigue in 2 cases. No Grade ≥3 toxicity was documented. Conclusion Oligometastatic patients treated with radical radio- therapy may achieve long-term progression-free survival, without significant treatment-related toxicity. While waiting for data from randomized trials, the use of radical radiation therapy in oligometastatic patients should be considered a valuable option, and its recommendation should be individualized. EP-1703 Exercise medicine is the new radiotherapy adjunct - when co-located and timetabled with treatment. N.A. Spry 1 , F. Singh 2 , D. Galvao 2 , D. Taaffe 2 , R. Chee 3 , M. Davis 4 , P. O'Brien 5 , R. Newton 2 1 Genesis Cancer Care Shenton House, Radiation Oncology, Joondalup, Australia 2 Edith Cowan University, Exercise Medicine Research Institute, Joondalup WA, Australia 3 GenesisCancerCare Shenton House, Radiation Oncology, Joondalup WA, Australia 4 Genesis Cancer Care, Radiation Oncology, Wembley WA, Australia 5 Genesis Cancer Care, Radiation Oncology, Newcastle NSW, Australia