ESTRO 2021 Abstract Book

S821

ESTRO 2021

Results Between August 2017 to August 2019, 102 patients were enrolled in the study. There were 65 patients with carcinoma oral cavity, 13 patients with carcinoma oropharynx, 11 patients with carcinoma larynx 6 patients with carcinoma nasopharynx, 6 patients with carcinoma hypopharynx, and one patient had unknown primary with neck nodal metastasis. Fifty eight patients (56.9%) received post-operative adjuvant radiotherapy, remaining 44 patients (43.1%) received radical radiotherapy. The median RT dose was 60 Gy. Sixty six patients (64.7%) received concurrent chemotherapy. The mean weight loss was 5.04 kgs (range: 2-14 kgs). Twenty four patients (23.5%) needed nasogastric tube / PEG tube during radiation. Mean PSSHN score at baseline was 230. The mean score at completion of RT was 146, mean decline in score was 84. The mean score at 3 months and 6 months post RT was 216 and 241 respectively. Normalcy of diet was the worst affected domain in PSSHN. Dmean and D95>50Gy for Middle pharyngeal constrictor (MPC) was associated with a significantly greater decline in the scores. Young age, weight loss of more than 5 kg and concurrent chemotherapy were found to be the significant predictive factors for PSSHN score decline. At median follow up of 24 months (range: 3 to 41 months), 3-year loco regional control, Disease free survival and overall survival were 68%, 51% and 66% respectively. Conclusion There is a significant decline in PSSHN score at completion of radiation with normalcy of diet being worst affected domain. There is almost complete recovery in score at 3 months post treatment, and further improvement in score at 6 months. All efforts should be taken to reduce doses to DARS, without compromising target coverage. PO-0988 Preliminary evaluation of head and neck malignancies with carbon ion radiotherapy at Osaka HIMAK A. Hasegawa 1 , M. Chatani 1 , O. Suzuki 1 , M. Anzai 1 , Y. Imai 1 , T. Fujii 2 1 Osaka Heavy Ion Therapy Center, Radiation therapy, Osaka, Japan; 2 Osaka International Cancer Institute, Head and Neck Surgery, Osaka, Japan Purpose or Objective In October 2018, the Osaka Heavy Ion Therapy Centre started carbon ion radiotherapy (CIRT) as the 6 th facility in Japan. This report aims to evaluate preliminary results of CIRT in patients (pts) with head and neck Between October 2018 and August 2020, a total of 51 pts with head and neck malignancies were treated with CIRT. The eligibility criteria were as follows: (1) histologically confirmed malignancy, (2) N0 or N1 M0 status, (3) inoperable tumors or refusal of surgery, (4) measurable gross tumors, (5) ECOG performance status of 0 to 3, (6) no previous history of RT for same lesion. The prescribed tumor doses were from 57.6 to 70.4 Gy (RBE) in 16 fractions over four weeks. Local response and toxicity were respectively evaluated using RECIST and CTCAE v.4.0 criteria. MRI was performed after treatment every 2-3 months in the first 2 years, every 4 months in the third year. Results The patients consisted of 24 males and 27 females aged from 20 to 92 years with a median age of 70 years. The most frequent primary site (63%) was the nasal and paranasal sinus. Majority of pts had mucosal malignant melanoma (31%), adenoid cystic carcinoma (29%), cT4a (26%) and cT4b (39%) stage. Thirty-one pts (61%) were irradiated with 64.0 Gy (RBE) and 14 pts (27 %) were with 57.6 Gy (RBE). Median follow-up time was 12.9 months (range, 3.5-26.4 months). Tumor response at 6 months using RECIST were complete response (CR) for 11 pts (22%), partial response (PR) for 20 pts (39%), stable disease (SD) for 18 pts (35%) and progressive disease (PD) for 2 pts (4%), with the effective rate (CR + PR) being 61%. In-field recurrence ware observed in 5 pts (2 pts with sarcoma, 2 pts with squamous cell carcinoma, 1 pts with mucosal malignant melanoma). In 5 pts, median local control time from the start of CIRT to recurrence was 6.7 months (range, 4.8-11.5 months). Forty-six pts (90%) without local recurrence were alive and were followed up at our hospital at the time of this analysis. Median local control time of 46 pts was 14.3 months (range, 3.9-26.4 months). Mucosal reaction during/at the end of treatment was G0, G1, G2 and G3 for 4 pts (8%), 2 pts (4%), 11 pts (22%) and 32 pts (65%), respectively. None of the patients required interruption of irradiation or administration of steroid due to mucositis. Acute mucosal reaction within 3 months was G0 and G1 for 40 pts (83%) and 8 pts (17%) pts, respectively. G2 acute skin reaction of all pts was observed in 15 pts (29%). In the analysis of late toxicities, one patient showed G2 osteonecrosis, 6 pts showed G2 otitis and 2 pts showed G3 optic neuritis. No unexpectable late severe toxicity was observed. Conclusion Our preliminary data of CIRT has shown acceptable toxicities and promising outcome for head and neck malignancies. However, a larger series of patients and a longer follow-up are needed to better investigate outcomes. PO-0989 Predictive factors for chemoradiotherapy-induced oral mucositis: Human papillomavirus influence Á. Fernández Forné 1 , M.J. García Anaya 1 , M.D. Toledo Serrano 1 , M. Muñoz Lupiáñez 1 , J.A. Medina Carmona 1 , J. Gómez-Millán Barrachina 1 1 Hospital Universitario Virgen de la Victoria, Radiation Oncology, Málaga, Spain Purpose or Objective The growing role of Human Papillomavirus (HPV), as a different entity, has led us to find head and neck cancer (HNC) in population without the usually associated risk factors. Mucositis is the most common, debilitating, and painful toxicity related to HNC chemoradiotherapy. Intensity Modulated Radiation Therapy (IMRT) allows us to offer greater precision, although has not been shown to reduce acute mucositis severity. The main malignancies at Osaka. Materials and Methods