Abstract book - ESTRO meets Asia

S59 ESTRO meets Asia 2018

Material and Methods Design : A prospective, pilot, randomized, double-blind, placebo-controlled clinical trial was conducted in 2014-16 (Alliance MC13C2). Patients were followed for 3 months post-RT. All patients completed study-related activities before trial closure. Setting : Three (3) hospitals; multicenter Participants : Thirty-two (2) eligible patients undergoing chemoradiptherapy for head and neck cancer (≥ 60 Gy) were included. They were required to be 18 years or older, with a histological confirmation of the tumor, ECOG performance status 0-2, able to initiate testing rinse within 3 days of starting RT and complete questionnaires, and with no major intercurrent medical issues. Patients with previous RT to the head and neck area, active connective tissue disease, or concurrent amifostine use were excluded. Interventions : The patient was given a 10% N- acetylcysteine (2,500 mg daily) or placebo rinse solution, and was instructed to orally gargle, swish, and split the testing solution 5 times daily during RT and for 2 weeks post-RT. Main Outcomes : The primary aim was to evaluate N- acetylcysteine’s ability to improve saliva viscosity by the GRIX questionnaire. Secondary aims included xerostomia improvement by GRIX and EORTC QLQ-H&N35 surveys, along with patient’s profile. The type I error rate for testing was set at 20% for the pilot trial. Results Seventeen (17) and 15 patients were in the placebo and N-acetylcysteine arms. Their baseline characteristics were balanced. The primary hypothesis, N-acetylcysteine being better by GRIX sticky saliva total score (Area-under-curve, P=0.12), was confirmed. Multiple secondary endpoints favored N-acetylcysteine including sticky saliva daytime, both xerostomia daytime and total, pain, and trouble with social eating scores. Repeated measures models confirmed these findings. The N-acetylcysteine rinse was well-tolerated. Conclusion The N-acetylcysteine rinse was safe, and we showed strong efficacious signals for improving thickened saliva and xerostomia by patient-reported outcome. A confirmatory phase III trial is required. PO-150 Dosimetric Predictors of Physician and Patient Rated- Xerostomia After IMRT in Nasopharyngeal Cancer K. Sommat 1 , W.S. Ong 2 , A. Hussain 1 , N.L.F. Yit 1 , J.B.K. Khoo 3 , Y.L. Soong 1 , K.W. Fong 1 , T.W.K. Tan 1 , J.T.S. Wee 1 1 National Cancer Center Singapore, Radiation Oncology Department, Singapore, Singapore 2 National Cancer Center Singapore, Clinical Trials and Epidemiological Sciences, Singapore, Singapore 3 National Cancer Center Singapore, Purpose or Objective The purpose of this study was to prospectively investigate the relation of physician and patient rated xerostomia with the 3D dose distribution in the parotid and submandibular glands and with clinical and treatment related factors. Material and Methods Between September 2004 and August 2012, 158 locally advanced NPC patients were included in this study. All patients were treated with IMRT and randomized to induction chemotherapy followed by concurrent chemo- IMRT or concurrent chemo-IMRT(CCRT) alone. The primary endpoints were defined as moderate-to-sevre physician- rated xerostomia(E1), patient-rated dry mouth(E2) and sticky saliva(E3) at 2-year after IMRT. Various clinical and Oncologic Imaging Departm ent, Singapore, Singapore

dosimetric parameters (eg, V40 [percentage of parotid volume receiving >40 Gy]) were obtained. Univariate and multivariate logistic regression analyses were performed. Results

Peak xerostomia toxicity was observed during CCRT week 7 and 8. The incidence of E1, E2, E3 at 2-year post IMRT were 21%. 26% and 36% respectively. The levels of xerostomia assessed by physicians(E1) were consistently lower than those assessed by patients(E2) over time(Cohen’s κ 0.23-0.39). Mean dose of parotids (Dmean) for all patients were between 31Gy to 61.5Gy and was not correlated with any of the endpoints. On multivariate analyses, receipt of induction GCP (OR=0.50 [0.23-1.09], p=0.083) and V60 of the contralateral parotid glands (OR=1.03 [0.99-1.07], p=0.080) were associated with near statistical significance with E1. V20 of the contralateral parotid glands (OR=0.96 [0.92-1.00], p=0.066) was the only potential predictor for E2. V20 of the ipsilateral parotid glands was the only parameter that was associated with near statistical significance for E3. Conclusion Dmean parotids of <26Gy could not be satisfactorily achieved with IMRT in patients with locally advanced NPC. Advanced radiotherapy techniques such as proton with potential dosimetric advantages should be evaluated in the treatment of NPC. Patient-reported assessment may better reflect the true incidence and severity of xerostomia. PO-151 Robotic fractionated stereotactic radiotherapy in recurrent hea d and neck cancers: Clinical outcomes S. Mishra 1 , T. Kataria 1 , S. Goyal 1 , R. Thiyagarajan 1 , D. Gupta 1 , S.S. Bisht 1 , S. Banerjee 1 , K. Narang 1 , R. Ratan 1 1 Medanta The Medicity, radiation oncology, Gurgaon, India Purpose or Objective Nearly 30% of head and neck cancers (HNC) recur following definitive therapy and only 20% of these recurrences are salvageable surgically. The rest were earlier relegated to palliative therapies. Reirradiation with either conventional fractionation (and concurrent chemotherapy) or fractionated stereotactic radiation