ESTRO 2021 Abstract Book

S253

ESTRO 2021

hyperthermia treatments is expected to depend strongly on temperature achieved, timing and sequence of modalities. The existence of a strong dose-effect relationship is confirmed by clinical results showing higher efficacy at tumor temperatures exceeding 41°C, and there are indications that shorter time intervals between hyperthermia and radiotherapy enhance synergistic effects. SP-0341 Clinical heating techniques, thermometry and quality assurance G. van Rhoon 1 , M. Paulides 2 , S. Curto 1 1 Erasmus MC Cancer Institute, Radiotherapy, Rotterdam, The Netherlands; 2 Eindhoven University of Technology, Electrical Engineering, Eindhoven, The Netherlands Abstract Text The early history of the clinical application of hyperthermia shows the classical pattern of initial excitement based upon the biological rationale but once transferred to clinical practice the initial enthusiasm was tempered by disappointment on the ability to adequately heat the target. Here after the persistent researchers continued with more realistic approaches and showed the benefit of adding adjuvant mild hyperthermia, i.e. temperatures ranging between 39°C to 44°C. In multiple randomized clinical trials a significant increased efficacy of thermoradiotherapy and thermochemotherapy has been demonstrated across multiple tumors, with both primary and recurrent indications. The clinical perseverance was also a strong stimulator for continuous innovation of the hyperthermia technology by both academia and industry. In the last decades a wide range of novel hyperthermia devices have been developed to adequately apply hyperthermia for different tumor pathologies and at varies body locations. Specific technologies are now available to apply hyperthermia to superficial and deep seated tumors using radiofrequency electromagnetic or ultrasound energy using phased array systems to focus the energy to the target volume. Novel technology was also developed for intraperitoneal and intravesical thermochemotherapy whereby clinical effectiveness and smooth integration in the treatment procedure translated in a broad adaptation of the procedure. Another important motivator for continuous improvement of hyperthermia technology were the retrospective clinical studies demonstrating the existence of an autonomous thermal dose effect relationship in thermo- radiotherapy for locally advanced cervical cancer and recurrent breast cancer. The strong developments in computational techniques and computing power enabled the introduction of personalized hyperthermia treatment planning (HTP) which after an initial period of maturing has become a powerful tool for optimizing the hyperthermia treatment quality, prior and during the application of the hyperthermia treatment. Real- time presentation of the applied energy distribution to the patient provides important information to the hyperthermia operator to better understand the actual temperature distribution monitored by the minimal- invasive temperature sensors as well as patient feedback. A major benefit is that on-line presentation of the energy distribution enables objective treatment optimization and it provides numerical indicators to assess treatment quality. Parallel to HTP, the introduction of magnetic resonance (MR) to measure the 3D temperature distribution during treatment provides a gate way for improved thermal dose assessment and guidance of treatment delivery. Perfusion monitoring during hyperthermia is an interesting future potential use of MR imaging. In addition, ongoing research aims at combining MR-thermometry with fast multi-physics modeling to enable real-time feedback control for automatic optimization of the thermal dose distribution during treatment. In summary, during the past 20 years hyperthermia technology has matured from an expertise and experience based delivery of the treatment towards a technology that is using real-time objective based information combined with the clinical evaluation of the patient condition to maximize thermal dose for an optimal treatment outcome. Abstract Text In Japan, the contribution of Professor Tsutomu Sugawara, a radiation biologist, of Kyoto University has led to a rapid increase in interest in hyperthermia from several sides, such as radiation therapy, chemotherapy and combined surgery. Activities related to the establishment of academic societies began in 1980s. The 1st Annual Meeting of Japanese Society of Hyperthermia was the official birthday of the Society, which was November 19, 1984. In the 1990-2000s, clinical trials were conducted at many major institutions, such as National Cancer Center and major University hospitals in Japan. Among them, many clinical studies on lung cancer have been conducted in Japan. In 2007, Dr. Mitsumori in Kyoto University reported a randomized controlled trial of whether hyperthermia was added to radiation alone for locally advanced non-small cell lung cancer. The local control rate was 29% in the radiation alone group and 68% in the hyperthermia combination group, showing good results in the hyperthermia group, One year survival rate of radiation alone was 38%, whereas 43% of the hyperthermia combination group with no statistical significance. It has been reported that there was no difference in side effects between the two groups. For esophageal cancer, many clinical studies were conducted in Japan using intracavitary hyperthermic devise. In 1995, Dr. Kitamura in Kyushu University reported the results of a randomized trial examining the effectiveness of hyperthermia in combination with preoperative chemoradiotherapy. The complete pathological response rate in the combination group was 25%, which was significantly better than 6% in the non-combination group. In addition, the 3-year survival rate has been reported to improve to 50% in the hyperthermia combination group and 24% in the non-hyperthermia combination group. One of leading clinical studies in Japan is a multicenter randomized trial of cervical cancer by Dr. Harima in Kansai Medical University, which was published in 2016. As a result of 101 cases of cervical cancer in stage II- SP-0342 Status of clinical hyperthermia in Japan H. Sakurai 1 1 University of Tsukuba, Radiation Oncology, Tsukuba, Ibaraki, Japan