ESTRO 2022 - Abstract Book

S440

Abstract book

ESTRO 2022

1 University Medical Center, University of Freiburg, Radiation Oncology, Freiburg, Germany; 2 Lindenhofspital, Radiation Oncology, Bern, Switzerland Purpose or Objective The treatment of unresectable local recurrences of superficial tumors in pre-irradiated areas is a major challenge when the option of re-irradiation (re-RT) using standard dose is questionable due to expected unacceptable toxicity. A novel treatment protocol of contact-free thermography-controlled superficial hyperthermia (HT) using water-filtered infrared-A (wIRA) irradiation immediately followed by hypofractionated re-RT of 20 Gy total dose (5 x 4 Gy, 1x/week) has shown a most favorable toxicity/efficacy profile in the treatment of large-sized, locally recurrent breast cancer (Notter et al., Cancers 2020). Different (radio-)sensitizing mechanisms of HT require different temperature ranges. Whereas the inhibition of DNA repair requires HT-levels ≥ 41.5°C, O 2 -dependent mechanisms can already operate at ≥ 39°C, and may be counteracted at temperatures ≥ 43°C. Using mild HT immediately before re-RT, O 2 -dependent radiosensitizing mechanisms thus may play a key role. Materials and Methods Experiments on healthy volunteers were performed using the wIRA-hyperthermia system hydrosun ® TWH1500 (Hydrosun, Germany) with approval of the local ethics committee. At automatically controlled maximum skin surface temperatures of 43°C, temperature profiles within the abdominal wall were measured with fiber optic sensors (OTG-M600, Opsens, Canada) at defined tissue depths of 1-20 mm. Corresponding pO 2 values were assessed with the OxyLite-Pro system (Oxford Optronix, UK). Hyperspectral tissue imaging (TIVITA, Diaspective Vision, Germany) was used to visualize the HbO 2 - oxygenation status of upper skin layers, and of superficial tumors in selected patients. Results Within 5-12 min of wIRA-exposure, mean skin surface temperatures increased from 34.6 to 41.6°C. Upon steady state conditions, mean maximum temperatures of 41.8°C were found at a tissue depth of 1 mm, with a steady decline in deeper layers (41.6°C @ 5 mm, 40.8°C @ 10 mm, 40.6°C @ 15 mm, 40.1°C @ 20 mm). Tissue heating was accompanied by a significant increase in tissue pO 2 , e.g., at a depth of 13 mm mean pO 2 rose from 46 to 81 mmHg. In the post-heating phase (+15 min), pO 2 was still elevated (72 mmHg), even though tissue temperatures had returned to normothermia (36.7°C). pO 2 values remained above baseline for 30-60 min post-heat. Non-invasive HbO 2 monitoring in the subpapillary dermis layer of normal skin and in recurrent breast cancers confirmed the improved O 2 status caused by wIRA-HT. Conclusion wIRA-hyperthermia (T = 39-43°C) leads to a distinct pO 2 rise in superficial tissues, which is essential for radiosensitization. This benefit of improved tissue oxygenation is only present if HT is applied shortly before radiotherapy. Effective HT levels needed for inhibition of DNA repair could be observed up to a tissue depth of ≈ 5 mm, as present, e.g., in lymphangiosis carcinomatosa. Effective HT levels for improved oxygenation (T ≥ 39°C) can be measured up to a tissue depth of ≈ 30 mm. Purpose or Objective Cervical esophageal cancer is rare subgroup for 5% to 10% of all esophageal cancers. Most of patients of cervical esophageal cancer needed hypopharyngectomy and laryngectomy for complete resection, and definitive CRT has been widely accepted treatment of choice for laryngeal preservation. There are few evidence studies have compared treatment outcomes between surgery and CRT in cervical esophageal cancer. Hence, we reviewed our institutional experiences to compare and tried to suggest the appropriate treatment directions for resectable cervical esophageal cancer. Materials and Methods A total of 197 patients were diagnosed as cervical esophageal cancer without distant metastasis between January 2001 and December 2020. Of those, 47 patients were excluded in this study because of unresectable stage (e.g. initial stage T4 or extensive nodal stage). Consequently, 100 patients had definitive chemoradiotherapy and 50 patients had surgery. In surgery group, 16 patients received preoperative treatment (CRT; 6 patients, CTx alone; 10 patients) and 16 patients received postoperative treatment (CRT; 6 patients, CTx alone, 6 patients, radiotherapy alone; 4 patients). Definitive CRT group patients received 5-fluorouracil/cisplatin based chemotherapy concurrently and were divided into high-dose group ( ≥ 59.4 Gy, n=71), and standard dose group (<59.4 Gy, n=29). Results The median follow-up was 30 months (5-225 months) for surviving patients. Of 50 patients with median age 63 in surgery group, 21 (42%), 9 (18%), 18 (36%), 2 (4%) patients were stage I, II, III and IV respectively. In contrast, patients in CRT group was statistically significant different in age (median 67) and stage as 19 (19%), 30 (30%), 44 (44%), 7 (7%) patients were stage I, II, III, IV. There was no statistically difference between CRT group and surgery group in overall survival(OS) (3 year OS : 61.2% vs 62.9%, p=0.976 ) and progression free survival (PFS) (3 year PFS : 47.5 % vs 53.0%, p=0.589). Treatment related toxicity (Grade ≥ 2) were significant higher in surgery group than CRT group (14(28%) vs 12 (12%), p=0.015), even only 6 patients received hypopharyngectomy and laryngectomy. In subgroup analysis between high-dose group and standard dose group, OS and loco-regional failure free survival (LRFS) was significantly higher in high-dose group (3 year OS : 65.4% vs 51.7%, p=0.046, 3 year LRFS 68.7% vs 42.5%). Poster Discussion: 12: GI PD-0491 Resectable cervical esophageal cancer : Surgery or definitive chemoradiotherapy with dose escalation J. Moon 1 1 Yonsei cancer center, Radiation oncology, Seoul, Korea Republic of