There’s a need for better treatment of extensive-stage small cell lung cancer; even with the introduction of immunotherapy most patients relapse within one year and very few patients are alive after 2-3 years. An older trial suggested that consolidation thoracic radiotherapy improves survival in patients who receive chemotherapy, that was their standard treatment back then, and there are preclinical studies suggesting that combining radiotherapy and immunotherapy might enhance the effect of the immunotherapy. So we performed this trial aiming to investigate whether the combination of thoracic radiotherapy and chemoimmunotherapy prolongs survival in these patients.
Could you outline the methodology?
Patients were randomised 1:1 to receive chemoimmunotherapy alone or chemoimmunotherapy plus thoracic radiotherapy of 30Gy in ten fractions, starting 3-4 weeks after the first chemoimmunotherapy infusions. Patients were then followed until progression and they received their maintenance immunotherapy as in previous studies.
What did you find?
Overall there was no survival benefit of adding thoracic radiotherapy to the chemoimmunotherapy. In fact, the survival curves are a little bit inferior in the experimental group. Again, there was no difference in PFS and overall there were more adverse events.
The most concerning observation was that there were more treatment-related deaths among the patients who received the experimental treatment.
What impact could these findings have?
There are several other ongoing trials investigating whether adding thoracic radiotherapy improves survival in this space with slightly different designs, most administer the TRT as consolidation of the chemoimmunotherapy. Of course we need to await the results of these trials before we can finally conclude but, until then, I would recommend that patients should not routinely receive thoracic radiotherapy except when they have symptoms from compression of central structures in their thorax, especially if they respond poorly to the chemoimmunotherapy.
