The consolidation paradox: rethinking thoracic radiotherapy in extensive-stage small cell lung cancer in the immunotherapy era
Year: 2026
Type: review
Abstract: The role of thoracic radiotherapy in extensive-stage small cell lung cancer (ES-SCLC) remains uncertain in the chemo-immunotherapy era. In the pre-immunotherapy era, the phase 3 CREST trial did not meet its primary overall-survival endpoint but showed reduced progression and higher 2-year overall survival rates with consolidative thoracic radiotherapy (cTRT). cTRT was not incorporated into the pivotal trials establishing chemo-immunotherapy as first-line treatment, leaving its contemporary role undefined. We reviewed the historical and contemporary evidence, grouping prospective studies by strategy: early concurrent radiotherapy during induction, post-induction consolidation during maintenance, low-dose immunomodulatory radiotherapy, and thoracic-only versus combined thoracic/extrathoracic irradiation. In the randomized phase 3 TRIPLEX trial, early concurrent radiotherapy during induction chemo-immunotherapy did not improve survival and was associated with more adverse events and non-progression deaths. In the randomized phase 2 TREASURE trial, conventional-dose cTRT during atezolizumab maintenance was associated with substantially higher rates of serious and fatal adverse events, together with marked lymphocyte depletion temporally associated with radiotherapy, although all patients had ECOG performance status 0-1; lower baseline DLCO was associated with fatal adverse events in an exploratory analysis. Single-arm studies (SAKK 15/19, a phase 2 adebrelimab study, and MATCH) did not report a comparable signal, but differences in design, dose, systemic agent, and adverse-event ascertainment preclude attributing this contrast to any single factor. A competing-risks analysis of TREASURE showed a numerically lower, non-significant cumulative incidence of overall radiologic progression with radiotherapy, with a numerically higher incidence of death without documented progression, and does not constitute evidence of reduced intrathoracic progression. Current evidence therefore does not support routine cTRT in ES-SCLC patients receiving chemo-immunotherapy, and conventional eligibility criteria may be insufficient to identify patients at risk of serious toxicity. We propose the term "Consolidation Paradox" for the hypothesis that improved systemic control may increase the value of residual thoracic disease control while narrowing the safety margin for thoracic irradiation. The ongoing randomized RAPTOR/NRG-LU007 trial will address the efficacy of post-induction consolidation; future trials should also record immune-cell dosimetry, stratify by pulmonary reserve, report thoracic progression separately, and analyze progression and death without progression as competing risks.
Source: Frontiers in Oncology
Institution: Azienda Sanitaria Unità Locale di Reggio Emilia
Language: English
Topic: Lung Cancer Research Studies
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,801
Award: G3584898954
OpenAlex ID: W7223133162