KEY POINTS
- This single-centre retrospective study included 82 patients with inoperable or surgery-declining stage III non-small cell lung cancer treated between March 2020 and March 2024. Median follow-up was 31.5 months.
- Carbon ion radiotherapy doses ranged from 48 to 78 Gy relative biological effectiveness, with a median of 72 Gy. Fractionation and systemic treatment varied substantially; 18 patients received carbon ion radiotherapy alone and 64 received combined treatment.
- One- and two-year overall survival rates were 85.4% and 65.9%, progression-free survival rates were 79.8% and 50.8%, and locoregional control rates were 95.3% and 82.9%. Median progression-free survival was 26 months; median overall survival was not reached.
- Combined immunotherapy was independently associated with improved overall survival (hazard ratio 0.41, 95% confidence interval 0.19–0.92; p=0.025). Because treatment allocation was non-randomized, this association does not establish causality.
- Grade 1 pneumonitis occurred in 6.1%, and esophagitis occurred in 47.6%, predominantly grade 1; no grade 3–4 pneumonitis or esophagitis was reported. Grade 3 or higher toxicity was mainly haematologic, led by grade 3 lymphopenia in 35.4%.
CLINICAL TAKEAWAY
Carbon ion radiotherapy produced encouraging locoregional control with limited high-grade thoracic toxicity in this selected cohort. However, the immunotherapy association is hypothesis-generating because prior and maintenance treatments were heterogeneous, long-term toxicity data were incomplete, and no photon or proton comparator was included; this is worth-attention evidence, not practice-changing.