ESTRO 2021 Abstract Book

S304

ESTRO 2021

Materials and Methods Since 08/2019, 29 (of 65) patients (9 female, 20 male) with motor deficits due to MSCC and a favorable survival prognosis according to a validated score have been included in a phase II trial (RAMSES-01). Median age is 68 (48-90) years, and most common tumor types are prostate cancer (n=10), breast cancer (n=7) and myeloma (n=6). RT regimens include 18x2.333 Gy (EQD2=43.2 Gy, n=10), 15x2.633 Gy (41.6 Gy, n=17; fewer fractions due to Covid-19 pandemic) and 12x2.663 Gy + 3x2.333 Gy (40.5 Gy, n=2; due to concurrent immunotherapy). Primary endpoint is local progression-free survival (LPFS=no progression of motor deficits during RT and no in-field recurrence following RT). Secondary goals include effect on motor function [improvement, overall response (OR) = at least no further progression] and sensory deficits, pain relief, overall survival (OS) and toxicity. Follow-up (FU) is performed until death or for 12 months. Results Three patients are currenty under treatment, one patient died after 14 Gy. Thus, 25 patients are evaluable for LPFS and response. LPFS is 100% at the end of RT (currently n=25), and at 1 month (n=21), 3 months (n=16), 6 months (n=9), 9 months (n=5) and 12 months (n=3) following RT. Considering best response during FU, OR and improvement rates are 100% and 60%, respectively. Sensory function normalized in 5 of the 9 patients (55.6%) with pre-RT sensory dysfunction. Of 21 patients with pain (median score 8, range 4-10), 18 (86%) achieved pain relief [complete in 7 patients (33%)]. OS-rates at 6 and 12 months are 71% and 71%, respectively. Six patients died (3 sepsis, 2 pneumonia, 1 tumor progression); death was not related to RT. RT- related grade 3 toxicity occurred in 2/25 (8%) patients (1 esophagitis, 1 diarrhea). Conclusion First results of high-precision RT with increased doses for MSCC in patients with favorable survival prognoses appear very promising with high response and LPFS rates and very few grade 3 toxicities. Updated information will be presented at the meeting. OC-0409 Salivary gland Radiotherapy for Sialorrhea Treatment in Amyotrophic Lateral Sclerosis patients. A. Assouline 1 , A. Schernberg 2 , M. del Mar Amador 3 , C. Morelot-Panzini 4 , J. Gonzalez-Bermejo 5 , T. Lenglet 3 , N. Le Forestier 3 , G. Bruneteau 3 , F. Salachas 3 , S. Delanian 1 , P. Pradat 3 1 Centre de Cancérologie de la Porte de Saint Cloud, Radiation Oncology, Boulogne Billancourt, France; 2 Centre de Cancérologie de la Porte de Saint Cloud, Radiation Oncology, Paris, France; 3 Paris ALS center, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris (APHP), Departement of Nervous System Diseases, Paris, France; 4 Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris (APHP), Departement of Pneumology , Paris, France; 5 Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris (APHP), Departement of Pneumology and Intensive Care, Paris, France Purpose or Objective This study was designed to evaluate the efficacy and safety of radiotherapy (RT) of the primary salivary glands in patients with amyotrophic lateral sclerosis (ALS) disease with refractory sialorrhea. Materials and Methods Patients refractory to conventional sialorrhea drug treatments treated in our institution between 2010 and 2020 were retrospectively analyzed, including firsts 50 patients prospectively analyzed. RT was delivered by a conventional LINAC, with 2 opposite beams including the two submandibular glands and two thirds of the two parotid glands before 2014, and from 2015 2 lateral beams including the submaxillary glands, and 2 opposite oblique beams directed to each parotid gland, with reduced oral cavity irradiation. The total dose delivered was 10 Gy in 2 fractions or 20 Gy in 4 fractions. RT efficacy was assessed using the 9-item Sialorrhea Scoring Scale (SSS), prospectively validated as the most effective and sensitive tool for measuring sialorrhea in ALS patients. Results Total 212 patients were included, and 254 treatments plans (42 reirradiations). Median age was 68 years (range: 38 - 95), 118 women (56%) and 94 men (44%). Median interval between the first and second radiotherapy course was 7.5 months (range: 1 - 37). The median SSS score before radiation therapy was 8 (range: 6 - 9), and the median SSS score at 1 month of irradiation was 2 (range: 1 - 6). There was no > grade 1 toxicities. At the end of RT, all but 1 patient had an improvement in SSS score: 246 had a complete response (CR) (96%, SSS 1-3) and 7 had a partial response (PR) (3%, SSS 4-5); one patient had a stable SSS score (<1%). CR 1 month after RT was achieved in 96% of the 212 patients who underwent a primary RT, and 100% of the 42 patients who received re-irradiation. Patients treated with 20Gy versus 10Gy during the first RT treatment were more likely to have a CR at 1 month (99% vs. 91%, p = 0.01), and had a greater decrease in SSS score (mean difference -6 vs. -5 points, p < 0.001). Also, the 42 patients who received reirradiation were more frequently previously treated with the RT 10Gy protocol (23/42 patients, 55%) versus 57/172 (33%) in patients who did not require reirradiation (p < 0.01). The 3-beam irradiation technique, used from 2014 and beyond, did not significantly improve treatment efficacy (reduction of the SSS score by -5.7 points on average versus -5.6 points previously, p = 0.5). Nevertheless, it reduced 1 month toxicity, in particular decreased saliva thickening discomfort (p < 0.001). Conclusion A 20 Gy irradiation in 4 fractions is an effective treatment for ALS patients with sialorrhea, with minimal toxicity, particularly by separately targeting parotid and submaxillary glands. A shorter RT (10 Gy in 2 fractions) may be proposed in patients with poor medical condition, subject to its lower efficacy and the greater need for reirradiation.

OC-0410 Adequacy of pain treatment in radiotherapy departments: a multicentric study (ARISE) C.M. Donati 1 , C.M. Donati 2 , E. Galofaro 3 , A. Zamagni 4,2 , G. Siepe 4 , F. Cellini 3,5 , A. Di Rito 6 , M. Portaluri 7 , C.