ESTRO 2021 Abstract Book

S441

ESTRO 2021

None of the patients had skin burning. Grade 1-2 toxicities were developed in 96% of the patients, consisting of sickness, vomits, diarrhea and/or fever). Two patients had grade 3 toxicity (sickness and diarrhea) and needed to be admitted to the hospital, recovering some days later. One of these two, was under capecitabine treatment, and was diagnosed with a dihydropirimidin dehydrogenase deficit changing for this reason chemotherapy line. There were no grade 4 toxicities.

Conclusion Modulated electro-hyperthermia concomitant to systemic oncological treatment was safe. mEHT is not a drug metabolized by the organism, and it is selective over malignant cells. These are probably some of the reasons why it does not increase toxicities from the systemic treatment. mEHT is a very promising treatment, as it can increase systemic and radiotherapy treatments effectiveness without increasing side effects for cancer patients. PH-0556 Thermo-Chemo-Radiotherapy: preliminary feasibility assessment in a single centre experience M. Fiore 1 , G. D'Ercole 1 , G.M. Petrianni 1 , L. Marinelli 1 , P. Trecca 1 , S. Ramella 1 1 Campus Bio-Medico University, Radiation Oncology, Rome, Italy Purpose or Objective Hyperthermia has been demonstrated to enhance the effect of radiation, chemotherapeutic agents, and immunotherapy, to trigger changes in perfusion and oxygenation of cancer, as well as to inhibit the DNA repair mechanisms. There is also evidence for immune stimulation and the induction of systemic immune responses. The aim of this study was to assess the feasibility of hyperthermia as a combined treatment. Materials and Methods From December 2019 to January 2021, patients with different histotypes were selected for combined therapy (radiotherapy, chemotherapy, radio-chemotherapy), including hyperthermia. We administered heat via radiative heating systems: BSD-500 for superficial treatments and BSD-2000 for deep regional treatments (Pyrexar Medical, Salt Lake City, USA) up to a temperature of 41-45 °C. All patients treated with deep regional hyperthermia underwent a CT simulation to plan a personalized treatment using SigmaHyperplan® TPS. During the treatment, the local temperature was controlled through thermometric probes applied close to the neoplasm. Furthermore, the patients’ vitals were monitored every ten minutes. Adverse events were analyzed according to National Common Terminology Criteria for Adverse Events (CTCAE), version 4.03. Results We treated 30 patients (mean age 64.5 years, range 21-87 years) with neoadjuvant (20%), adjuvant (13.3%) or radical (66.7%) intent. Among them, hyperthermia was combined with radio-chemotherapy in 9 cases (30%), with radiotherapy in 17 cases (56.7%) and with chemotherapy in 4 patients (13.3%). The patients were affected by primary locally advanced or recurrences of abdomen, pelvis or extremities. Most patients (96.6%) received treatment without relevant toxicity with a very high acceptance. Only one patient developed localized or diffuse power-dependent discomfort during the regional hyperthermia in the pelvic region. No other relevant toxicity has been reported. Notably, there were no interruptions in any patients during radiotherapy and/or systemic treatment, due to hyperthermia. At the time of analysis, clinical and radiological re-evaluation was performed in fifteen patients after the combined therapy: four patients had a complete response (26.7%), eight patients a partial response (53.3%), one patient a stable disease (6.7%) and two patient a progression of disease (13.3%). Conclusion The integration of radiative hyperthermia to radiotherapy and chemotherapy is feasible and tolerable. These preliminary findings encourage us to continue this integrated strategy.

Proffered papers: Highlights of proffered papers - Best Papers and Paper Awards

OC-0557 AI-based NSCLC detection and segmentation: faster and more prognostic than manual segmentation S. Primakov 1 , A. Ibrahim 1,2,3,4 , J. van Timmeren 5 , G. Wu 1 , S. Keek 1 , M. Beuque 1 , R. Granzier 6 , M. Scrivener 7 , S. Sanduleanu 1 , E. Kayan 1 , I. Halilaj 1 , J. Wu 8 , R. Monshouwer 9 , H. Gietema 10 , L. Hendriks 11 , O. Morin 12 , A. Jochems 1 , H. Woodruff 1,10 , P. Lambin 1,10 1 Maastricht University, Precision Medicine, Maastricht, The Netherlands; 2 Maastricht University, Nuclear Medicine, Maastricht, The Netherlands; 3 Hospital Center Universitaire De Liege, Medical Physics, Liege,