Consolidative Thoracic Radiotherapy Shows Limited Clinical Benefit in Extensive-Stage SCLC
Key Clinical Takeaways
- Design/Population: This multicenter, single-arm phase 2 trial evaluated consolidative thoracic radiotherapy after carboplatin/etoposide plus durvalumab in 46 patients with extensive-stage SCLC and ECOG performance status ≤1. Thoracic radiotherapy (39 Gy in 13 fractions) was delivered within 5 weeks of completing chemoimmunotherapy, with optional prophylactic cranial irradiation.
- Key Outcomes: The study did not meet its primary end point, with a 12-month progression-free rate of 15.6%, below the predefined threshold of ≥25%. Median PFS was 6.4 months, and median OS was 15 months, consistent with historical chemoimmunotherapy outcomes.
- Clinical Relevance: Although consolidative thoracic radiotherapy did not improve PFR following chemoimmunotherapy, the regimen was well tolerated with no severe thoracic radiotherapy-related toxicities. Ongoing phase 3 trials, including RAPTOR, will help determine whether thoracic radiotherapy should be incorporated routinely into ES-SCLC treatment paradigms in the immunotherapy era.
According to results from the phase 2 SAKK 15-19 trial, consolidative thoracic radiotherapy after chemoimmunotherapy showed limited clinical benefit for patients with extensive-stage small cell lung cancer (ES-SCLC).
In this single-arm study, 46 patients received carboplatin (AUC5) plus 100 mg/m² of etoposide on days 1 through 3 and 1500 mg of durvalumab on day 1 for 4 cycles, followed by maintenance durvalumab every 4 weeks for up to 2 years in the absence of disease progression. Thoracic radiotherapy was delivered within 5 weeks of completing chemoimmunotherapy, and prophylactic cranial irradiation was permitted. The primary end point was 12-month progression-free rate. Key secondary end points included progression-free survival (PFS), overall survival (OS), and safety.
At a median follow-up of 29 months, the 12-month progression-free rate was 15.6%. Median PFS was 6.4 months, and median OS was 15.0 months. Grade 3/4 treatment-related adverse events occurred in 23.9% of patients, most frequently neutropenia (23.9%) and thrombocytopenia (8.4%). One treatment-related death due to sepsis was reported. No severe thoracic radiotherapy-related toxicities occurred.
“Adding consolidative [thoracic radiotherapy] after chemotherapy plus durvalumab in ES-SCLC didn’t meet the primary endpoint of the expected 12-month PFR,” concluded Dr Addeo et al. “Ongoing larger Phase III trials, including RAPTOR (LNRG LU007), will further define [thoracic radiotherapy]’s role in this setting.”
Source:
Addeo A, Dietrich D, Mach N, et al. Thoracic radiotherapy plus maintenance durvalumab after first line carboplatin and etoposide plus durvalumab in extensive-stage disease small cell lung cancer (ES-SCLC) – A multicenter single arm open label phase II trial (SAKK 15/19). Eur J Cancer. Published online: November 28, 2025. doi:10.1016/j.ejca.2025.116138
