Clinical Summary:

• Design/Population: This phase 3 randomized trial evaluated the addition of concurrent thoracic radiotherapy to platinum/etoposide chemotherapy plus durvalumab in patients with extensive-stage small cell lung cancer. The study planned to enroll approximately 302 patients but was stopped early because of safety concerns and a preplanned interim analysis showing no evidence of survival benefit.
• Key Outcomes: The addition of thoracic radiotherapy did not improve the primary endpoint of overall survival or progression-free survival compared with chemoimmunotherapy alone. The experimental arm experienced more adverse events and more treatment-related deaths, prompting early study termination. 
• Clinical Relevance: These data do not support the routine use of concurrent thoracic radiotherapy with chemoimmunotherapy in patients with extensive-stage small cell lung cancer. Thoracic radiotherapy should remain reserved for symptom palliation outside of clinical trials until results from ongoing studies of consolidation thoracic radiotherapy become available.

Bjørn Henning Grønberg, MD, PhD, professor and consultant in oncology at the Norwegian University of Science and Technology and St. Olavs Hospital in Trondheim, Norway, discusses results from a phase 3 randomized trial evaluating the addition of concurrent thoracic radiotherapy to platinum/etoposide chemotherapy plus durvalumab in patients with extensive-stage small cell lung cancer. The study investigated whether delivering thoracic radiotherapy between the second and third immunotherapy cycles could improve outcomes compared with chemoimmunotherapy alone.

The trial was stopped early because of safety concerns and a preplanned interim analysis showing no evidence of benefit. The addition of thoracic radiotherapy did not improve progression-free survival or overall survival and was associated with higher rates of adverse events and treatment-related deaths. According to Grønberg, these findings are consistent with results from the TREASURE trial and suggest that routine use of thoracic radiotherapy with chemoimmunotherapy should be avoided outside of clinical trials, except when needed for palliation of thoracic symptoms.

Dr Grønberg presented these findings at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.

Transcript:

Hi, my name is Bjørn Henning Grønberg. I’m a professor and consultant in oncology at the Norwegian University of Science and Technology and St. Olavs Hospital in Trondheim, Norway. On behalf of my colleagues in Norway, Sweden, Estonia, the Netherlands, and Iceland, I had the pleasure of presenting results of our phase 3 trial investigating whether adding thoracic radiotherapy improves survival among patients with extensive-stage small cell lung cancer who receive chemoimmunotherapy.

The background of the trial is that there is definitely a need for better treatment even with the introduction of immunotherapy. We see that most patients relapse within 1 to 2 years.

There were data from an older Dutch trial indicating that consolidation thoracic radiotherapy improves survival among patients who receive chemotherapy alone. That was the standard treatment before immunotherapy was established. There are also several preclinical studies indicating that there is a synergistic effect of giving radiotherapy concurrently with immunotherapy.

So we designed this trial investigating whether thoracic radiotherapy of 30 Gy in 10 fractions, given between the second and third immunotherapy cycles, improved survival compared with chemoimmunotherapy alone.

The plan was to randomize approximately 302 patients, but the study was closed prematurely due to safety concerns and also a preplanned interim analysis that did not show any indication of a survival benefit.

Overall, we did not see any signs of an improvement in either progression-free survival or overall survival, which was the primary endpoint.

Overall, there were more adverse events in the experimental group, but I think the main concern is that there were also more treatment-related deaths. It is not easy to understand the mechanisms because there was quite a wide range of adverse events leading to death, but the numbers were quite clear.

So we conclude that thoracic radiotherapy should not be given routinely to these patients but should still be considered for patients who have symptoms from tumor compression in the thorax.

These data are actually quite similar to data from the only other randomized trial investigating thoracic radiotherapy in extensive-stage small cell lung cancer. Those data were presented at ESMO in 2023 from the German TREASURE trial. That trial was also closed prematurely, and they also observed more treatment-related deaths and, again, a wide spectrum of adverse events leading to death.

I know there are other ongoing trials. Most of them give consolidation thoracic radiotherapy after chemoimmunotherapy, and, of course, we need to see the results of those before we can finally draw conclusions. But unless patients are enrolled in a clinical trial, I would say that we should not give thoracic radiotherapy in this patient group.

Thank you for your interest in our trial.

Source:

Grønberg BH, Dumoulin DW, Oselin K, De Petris L, Neumann K, Madebo T, et al. Concurrent thoracic radiotherapy (TRT), platinum/etoposide chemotherapy, and durvalumab immunotherapy in extensive-stage (ES) small cell lung cancer (SCLC): A phase III trial. Presented at the ASCO Annual Meeting. 2026.