Thoracic Consolidation Plus SBRT to Cranial Mets May Improve OS in ES-SCLC

Given the modest improvement of immunotherapy when added to platinum-based doublet chemotherapy, investigators sought to improve outcomes for patients diagnosed with ES-SCLC, in which the tumor extends beyond what can be treated with a definitive radiation field.

The addition of thoracic consolidation or stereotactic body radiation therapy (SBRT) administered to cranial metastases after chemoimmunotherapy or chemotherapy alone may be associated with a significant improvement in overall survival (OS) vs platinum-doublet chemotherapy alone or with immunotherapy in patients with extensive-stage small cell lung cancer (ES-SCLC), according to results from a single-center, retrospective cohort study presented at the IASLC 2025 World Conference on Lung Cancer (WCLC).

Efficacy data revealed that among patients with ES-SCLC treated with SBRT to extracranial metastases (n = 12), the median OS was 6.5 months vs 8.9 months in patients not treated with radiotherapy (n = 114; HR, 1.381; 95% CI, 0.7574-2.517; P = .5222). However, an OS improvement was observed with SBRT administered to cranial metastases vs patients not treated with radiotherapy, at 24.4 months (HR, 0.3658; 95% CI, 0.1603-0.8348; P = .0594). Furthermore, patients treated with thoracic consolidation in addition to chemotherapy with or without immunotherapy (n = 18) displayed a median OS of 18.9 months vs 8.9 months without thoracic consolidation (HR, 0.4730; 95% CI, 0.2785-0.8034; P = .0189).

Additionally, among patients treated with chemoimmunotherapy alone (n = 70), the median OS was 9.5 months, with neither the addition of extracranial (n = 6) nor cranial SBRT (n = 2), at 8.3 months (HR, 1.161; 95% CI, 0.4691-2.873; P = .7102) and 18.2 months (HR, 0.8694; 95% CI, 0.2283-3.310; P = .7145), respectively, showing significantly improved OS. By contrast, the addition of thoracic consolidation showed a trend towards improved OS, with a median of 20.7 months (HR, 0.4722; 95% CI, 0.1710-1.304; P = .1388).

“[This] study suggests that thoracic consolidation and SBRT to cranial metastases may be associated with improved [OS] in patients with ES-SCLC following induction therapy, with this trend maintained after addition of immunotherapy,” Helen Gandler, a resident physician of Internal Medicine at Temple University Hospital, wrote in the presentation with study coinvestigators. “In contrast, SBRT to extracranial metastases did not yield a survival benefit. While limited by small sample size and potential selection bias, these findings support further prospective investigation into the role of [radiotherapy], particularly [thoracic consolidation], in the management of ES-SCLC in the era of chemoimmunotherapy.”

The retrospective cohort study identified and treated patients with ES-SCLC with chemotherapy or chemoimmunotherapy and compared outcomes among those who did (n = 29) or did not receive subsequent radiotherapy (n = 114) from January 1, 2013, to December 30, 2023. Specifically, the receipt of chemotherapy with or without immunotherapy or chemoimmunotherapy alone was compared to the receipt of subsequent radiation therapy consisting of SBRT to extracranial or cranial metastases, or thoracic consolidation.

The median dose of extracranial SBRT, cranial SBRT, and thoracic consolidation was 2000 cGy (range, 800-3000), 2000 cGy (range, 1800-3300), and 4500 cGy (range, 2000-12000), respectively.

Given the modest improvement of immunotherapy when added to platinum-based doublet chemotherapy, investigators sought to improve outcomes for patients diagnosed with ES-SCLC, in which the tumor extends beyond what can be treated with a definitive radiation field. According to a narrative review of radiotherapy for the oligometastatic treatment of lung cancer published in Cancers, radiotherapy is often considered to treat intracranial disease, as these metastases are considered resistant to drug therapies due to the presence of the blood-brain barrier, but the role of radiotherapy is poorly defined.2 The study authors sought to better define the role of radiation therapy, particularly SBRT, to oligometastatic sites or thoracic consolidation following chemotherapy or chemoimmunotherapy induction to improve outcomes among this patient population.

References

1. Gandler H, Adavelly P, Desai P. ES-SCLC outcomes following SBRT and/or thoracic consolidation after induction systemic therapy. Presented at: IASLC 2025 World Conference on Lung Cancer. September 6-9, 2025. Barcelona, Spain. EP.13.24
2. Shirai K, Endo M, Aoki S, et al. Efficacy of radiotherapy for oligometastatic lung cancer and irradiation methods based on metastatic site. Cancers (Basel). 2025;17(15):2569. doi: 10.3390/cancers17152569.