Sequential Thoracic Radiotherapy After Chemoimmunotherapy Associated With Improved Survival in ES-SCLC
Key Clinical Summary:
- Design/Population: A multicenter retrospective study of 280 patients with extensive-stage small cell lung cancer (ES-SCLC) treated between January 2020 and July 2024 evaluated outcomes of concurrent chemoimmuno-radiotherapy versus sequential chemoimmuno-radiotherapy following first-line chemoimmunotherapy, with propensity score matching and analysis of time-corrected biologically effective dose.
- Key Outcomes: In the overall cohort (median PFS 8.7 months, OS 20.6 months), sequential TRT was associated with significantly improved PFS (HR 0.67; P = 0.008) and OS (HR 0.70; P = 0.048) compared with concurrent TRT, along with fewer treatment-related adverse events. Among concurrent TRT recipients, lower tBED ( ≤ 50 Gy) was associated with better OS (HR 2.24; P = 0.028) and PFS (HR 2.27; P = 0.014). Age, KPS, tBED, and metastatic burden were independent prognostic factors.
- Clinical Relevance: In ES-SCLC receiving chemoimmunotherapy, sequential thoracic radiotherapy may offer superior survival and safety compared with concurrent administration. For patients treated concurrently, lower radiation intensity (tBED ≤ 50 Gy) may optimize outcomes, informing timing and dosing strategies pending prospective validation.
Sequential thoracic radiotherapy (TRT) following first-line chemoimmunotherapy (CIT) was associated with improved progression-free (PFS) and overall survival (OS) compared with concurrent administration among patients with extensive-stage small cell lung cancer (ES-SCLC), according to a multicenter retrospective analysis.
Patients with ES-SCLC continue to experience rapid progression or death due to recurring disease, despite high objective response rates to initial systemic therapy, highlighting the need for more effective treatment options.
“[W]ithin the context of immunotherapy, the overall risk–benefit assessment of thoracic radiotherapy for ES-SCLC still requires elucidation through high-quality evidence,” wrote Hao Zhou, MD, Shandong Cancer Hospital and Institute Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, China, and co-authors.
Patients were stratified into concurrent chemoimmuno-radiotherapy (CCIRT; thoracic radiotherapy delivered during chemoimmunotherapy) or sequential chemoimmuno-radiotherapy (SCIRT; thoracic radiotherapy delivered after chemoimmunotherapy). Propensity score matching was performed to minimize selection bias. Radiation dose and fractionation were further analyzed using time-corrected biological effective dose (tBED).
The primary end points were progression-free survival (PFS), overall survival (OS), and treatment-related adverse events (TRAEs).
This study included 280 ES-SCLC patients treated between January 2020 and July 2024 who received both chemoimmunotherapy and thoracic radiotherapy, of which 78 received concurrent chemoimmuno-radiotherapy and 202 received sequential chemoimmuno-radiotherapy.
In the overall cohort, the median PFS was 8.7 months, and the median OS was 20.6 months. The sequential chemoimmuno-radiotherapy group demonstrated significantly longer PFS (hazard ratio [HR] = 0.67, 95% confidence interval [CI], 0.50 to 0.90; P = 0.008) and OS (HR = 0.70; 95% CI, 0.50 to 0.99; P = 0.048) compared with the concurrent chemoimmuno-radiotherapy group, along with a lower incidence of treatment-related adverse events. Within the concurrent chemoimmuno-radiotherapy subgroup, a lower tBED (≤ 50 Gy) was associated with improved OS (HR = 2.24; 95% CI, 1.07 to 4.68; P = 0.028) and PFS (HR = 2.27; 95% CI, 1.64 to 4.42, P = 0.014).
Multivariable analysis identified age, Karnofsky Performance Status (KPS), tBED, and distant metastasis status as independent prognostic factors for survival outcomes, while sex, KPS, tBED, and brain metastasis status were associated with TRAEs.
Dr Zhou and co-authors concluded, “an integrative evaluation of efficacy and safety demonstrates that thoracic radiotherapy delivered after CIT is superior to concurrent radiotherapy with CIT.”
“For patients receiving concurrent thoracic radiotherapy, a low-tBED regimen may yield superior prognostic outcomes compared to a high-tBED regimen,” they added.
Source:
Zhou H, Zhao H, Shi S, et al. Timing, fractionation, and dose of thoracic radiotherapy in patients with extensive-stage small cell lung cancer undergoing first-line Chemo-Immunotherapy. Clinical and Translational Radiation Oncology. Published online February 5, 2026. doi:10.1016/j.ctro.2026.101114
