This registry study from Japan reported outcomes of 274 patients with operable lung cancer treated with proton (n=138, 50 %) and carbon ion (n=136, 50 %). Peripherally situated tumors were 91%. With a median follow-up of 42.8 months, 3-year PFS was 80.5 % and OS was 92.5 %; grade ≥3 treatment-related toxicity was observed in 4 cases (1.5 %). particle-ion type were not significantly associated with PFS. The authors concluded that particle therapy for operable early-stage lung cancer resulted in excellent 3-year OS and PFS in each subset, and both are feasible alternatives to curative surgery.