KEY POINTS
- TREASURE was a multicenter open-label phase 2 randomized trial in Germany and Austria, enrolling patients with extensive-stage small cell lung cancer and at least stable disease after carboplatin, etoposide, and atezolizumab induction.
- 68 patients were randomized to atezolizumab maintenance plus consolidative thoracic radiotherapy (30 Gy in 10 fractions) or atezolizumab maintenance alone; recruitment was stopped early because of safety concerns.
- Median overall survival was numerically shorter with thoracic radiotherapy plus atezolizumab — 6.7 vs 13.4 months, hazard ratio 1.55, 95% confidence interval 0.90–2.69, p = 0.34.
- Median progression-free survival was similar — 2.4 vs 2.6 months, hazard ratio 0.92, 95% confidence interval 0.54–1.55, p = 0.85.
- Serious adverse events were more frequent with thoracic radiotherapy plus atezolizumab — 61.3% vs 18.2%, p < 0.001 — and fatal adverse events were also higher: 19.4% vs 3.0%, p = 0.04.
CLINICAL TAKEAWAY
TREASURE argues against routine consolidative thoracic radiotherapy during atezolizumab maintenance for unselected patients with extensive-stage small cell lung cancer. The key signal is not efficacy but safety: more serious and fatal events, with persistent lymphocyte depletion after thoracic radiotherapy as a possible contributor. Because the trial stopped early and was underpowered for efficacy, this is a cautionary randomized phase 2 result, not the final word on carefully selected patients.