Final survival data from a randomized phase II trial comparing high-dose with standard-dose twice-daily (BID) thoracic radiotherapy (TRT) in limited stage small-cell lung cancer (LS SCLC).

• DOI: 10.1200/jco.2023.41.16_suppl.8512
• Publication Date: 2023-06-04T16:12:44Z
• Authors: Bjorn H. Henning ...; Kristin Toftaker ...; Øystein Fløtten; Maria Moksnes Bja...; Tesfaye Madebo; Tine Schytte; Seppo Wang Langer; Signe Leonora Ris...; Nina Helbekkmo; Kirill Neumann; Odd Terje Brustugun; Øyvind Yksnøy; Georgios Tsakonas; Jens Engleson; Sverre Fluge; Thor Naustdal; Liv Ellen Giske; Jan Nyman; Tarje Onsøien Hal...
• Keywords: Prophylactic cranial irradiation; Clinical endpoint

8512 Background: Concurrent chemotherapy and TRT is standard treatment of LS SCLC. BID 45 Gy/30 fractions the most recommended schedule. Trials report 5-year survival rates up to 36%, illustrating that some are cured but also need for better treatment. Many failures due relapses within fields, it has been proposed higher doses might improve local control consequently survival. However, high-dose once-daily (QD) 66-70 Gy do not prolong We investigated whether 60 Gy/40 was tolerable improved compared with established schedule (NCT02041845). Primary analyses presented at ASCO 2020 showed trial highly positive primary endpoint, 2-year (60 Gy: 74.2%, 48.1%, OR 3.09 [95% CI 1.62-5.89]; p=0.0005). now present updated final data. Methods: Patients ≥18 years PS 0-2, confirmed SCLC, according IASLC definition after PET CT staging received 4 courses platinum/etoposide were randomized receive or lesions. started concurrently 2 nd course. Responders offered QD prophylactic cranial irradiation 25-30 Gy. All patients followed 5 until death. Results: 170 eligible 22 Scandinavian hospitals from 2014-2018 n=89, n=81). Median age 65, 31.2% ≥70 years, 57.1% women, 89.4% had 0-1, 83.5% stage III disease, 7.6% pleural effusion 20.0% ≥5% weight loss last three months before enrollment. Baseline patient disease characteristics planning target volumes well balanced between arms. Completion 92.1%, 87.7%) 96.6%, 91.4%) similar. on arm did experience more grade 3-4 esophagitis 21.2%, 18.2%; p=0.83) pneumonitis 3.4%, 0.0%; p=0.39), other toxicity related deaths. The group numerically longer PFS (median 18.6 11.6-25.6], 10.9 8.7-13.2], HR 0.76 0.53-1.08]; p=0.13). Results endpoint remain unchanged. dose significantly prolonged OS 43.5 30.4-56.6], 22.6 17.2-28.0], 0.69 [0.48-0.99]; p=0.043) provided 4.5 year rate 41.6% 28.4% 18.9-39.5], OR: 1.79 0.95-3.41]). will be meeting. Conclusions: Compared SCLC who TRT, receiving toxicity, a substantial prolongation much long term rate. Clinical information: NCT02041845 .