163 consecutively treated patients with biopsy-proven, stage III NSCLC who received IMPT (n = 35, 21%) or IMRT (n = 128, 79%) were analyzed in this study. Median RT dose was 60 (range, 45-72) Gy [RBE]. This study found no difference in OS, FFDM, and FFLR between the two RT modalities. IMPT provided significant dosimetric pulmonary and cardiac sparing when compared to IMRT. IMPT was associated with a reduced rate of grade ≥3 pneumonitis (HR 0.25, P = .04) and grade ≥3 cardiac events (HR 0.33, P = .08). The authors suggested that IMPT may provide a safer treatment option, particularly for high-risk patients with poor pretreatment pulmonary function.