Acute radiation morbidities and dosimetric evaluation of DARS structures: Results from the phase III randomized SWOAR trial.

• DOI: 10.1200/jco.2024.42.23_suppl.tps149
• Publication Date: 2024-08-12T13:39:32Z
• Authors: Aman Sharma; Abiramasundari Vi...; Adrija Ghosh; Jitendra Kumar Meena; Rajeev Kumar; Abhilash Dagar; Akash Kumar; Abhinav Singhal; Suchita Singh; Kalpa Das; Ashutosh Mishra; Dyuti Shah; Tenzin Choden; Yousra Izzuddeen; Supriya Mallick; Subramani Vellaiyan; Atul Sharma; Alok Thakar; Suman Bhasker; Daya Nand Sharma

TPS149 Background: The SWOAR is a phase III trial (ClinicalTrials.gov ID NCT05187091) evaluating sparing of dysphagia/aspiration related structures (DARS) & submandibular gland by IMRT. Methods: Patients with T1-4, N0-3, M0 oropharynx, larynx and hypopharynx treated radical RT were randomized to arm A (standard IMRT) or B (DARS in 1:1 manner. Treatment allocation was done based on T stage, concurrent chemotherapy use (weekly 40mg/m 2 ) subsite. A10-point improvement MD Anderson Dysphagia Inventory (MDADI) composite score (primary end point study) at 6 months post SD 17, power as 90% two-sided alpha 5% estimated sample size. SIB IMRT delivered dose 66Gy (gross disease+0.5cm), 54Gy disease+1cms+regional lymphatics) 30 fractions. Acute radiation morbidities scored RTOG scoring criteria. Aspiration prevention assessment PAS measured FEES. Results: total 166 patients till date have been enrolled, 81 Arm 85 B. Median age 58 years, 73.4% had oropharyngeal primary, 89% stage III-IV received chemotherapy. MDADI scores pre-RT 70.5 (IQR 56.8-75.8) 69.5 (56.8-75.8) Post-RT median dropped 54.2 (48.8-60) 54.8 (51.6-65.3) Reduction pre 11.1 (0-21) 7.9 (0-20) (p=0.28). Pre RT-PAS similar both arms 1 (IOR 1-2), post-RT (1-2) (1-1). mean SCM 56.2Gy (46.8Gy-61.2Gy) vs 48.9Gy (36Gy-57.6Gy) p<0.003, MCM 58.5Gy (52.7Gy-63.1Gy) (47.8-63.6) p=0.11, ICM 48.5Gy (46.8Gy-57.7Gy) 37.8Gy (26.5-62.4) p<0.001, base tongue 60.5Gy (53.9Gy-64.3Gy) 53.9Gy (40.2Gy-62.4Gy) p=0.001,supraglottic 57.7Gy (49.2Gy-64.4Gy) (46.7-64.6) p=0.63, 46.0Gy(42.4Gy-53.7Gy) 28.3Gy (21.5Gy-49Gy) cricopharyngeus 46.0Gy(43.6Gy-49.9Gy) 32.6Gy (27.3Gy-47Gy) esophageal inlet 44.6Gy (41.3Gy-47.9Gy) 27.2Gy (22.8Gy-39.1Gy) contralateral 52.8Gy (48.5Gy-57.2Gy) 40.4Gy (37.3-49.6) all respectively. grade 3 occurred 68.4% 54.4% B, p=0.07. mucositis developed 34.2% 16.7% p=0.009. Conclusions: Swallowing-sparing significantly reduced the DARS (except middle constrictor muscle supra glottic larynx). Dosimetric advantage gained delivery resulted significant reduction development acute showed trend towards toxicities. Clinical information: NCT05187091 .