P64.04 Hypo-Fractionated Versus Conventionally Fractionated Radiotherapy for Patients with LS-SCLC: An Open-Label, Randomized, Phase 3 Trial

Concurrent chemoradiotherapy (CRT) is the standard treatment of limited-stage small-cell lung cancer (LS-SCLC). Various radiation schedules in CRT are commonly used, because CONVERT phase III trial suggested comparable survival outcomes with similar toxicity profiles once-daily radiotherapy 66 Gy (conventionally fractionated radiotherapy, CFRT) over twice-daily (BID) 45 Gy. However, has not been widely adopted clinically, due to logistical issues its delivery. Recently, characterized by improved dose conformality tumor target and reduced normal tissue exposure, intensity-modulated therapy (IMRT) used widely, making hypo-fractionated (HFRT) for LS-SCLC feasible tolerable. Here, we aim design a compare efficacy HFRT CFRT patients. This multicenter, open-label, III, randomized aims enroll approximately 540 patients cytologically or histologically confirmed LS-SCLC, aged 18 70 years, ECOG performance status 0-2, adequate cadiopulmonary function. Stratified institution stage, participants randomly assigned (1:1) receive either (45 Gy/15 fractions) (60 Gy/30 fractions). Both groups one fraction per day five fractions week. All complete four six courses intravenous cisplatin 75 mg/m2 carboplatin (area under curve 5 mg/mL × min, Calvert's formula) on 1 etoposide 100 days 1-3 every 3 weeks. Thoracic starts no later than first 3rd course platinum-etoposide. Responders recommended prophylactic cranial irradiation 25 10 fractions. The primary endpoint 2-year overall secondary objectives include progression-free survival, local-regional control toxicities. study started Feb 2016, 373 have accrued as Mar 31, 2021. Trial registration: ClinicalTrials.gov: NCT02688036. Registered 23 February, 2016. ▪▪▪