Comparison of risk and predictors for early radiation pneumonitis in patients with locally advanced non-small cell lung cancer treated with radiotherapy with or without surgery

• The study is a prospective non-randomized concurrent control trial. Risk of radiation pneumonitis was investigated in surgical and non-surgical group.
• Higher risk of radiation pneumonitis was found in surgical group.
• Lower tolerance of lung to radiotherapy was found in surgical group.
• Mean heart dose was a predictor for radiation pneumonitis only in surgical group.

ObjectivesTo investigate risk and predictors for radiation pneumonitis (RP) and tolerance of lung to radiation in patients treated with thoracic radiotherapy (RT) with or without surgery.Methods and materialsA total of 433 consecutive patients with locally advanced non-small cell lung cancer were followed after three-dimensional conformal radiotherapy. Among them 284 received RT without surgical intervention and 149 received postoperative radiotherapy (PORT). RP was graded according to Common Terminology Criteria for Adverse Events version 4.0.ResultsThe rate of grade ≥2 and grade ≥3 RP was 50 and 16% in the PORT group compared with 38 and 9% in the non-surgical group (p < 0.05 for each comparison). The lung volume was significantly smaller in PORT group than in no-surgical group (3181 ± 915 cm3 vs. 4010 ± 1120 cm3, p < 0.05). Age, chemotherapy, mean lung dose (MLD) and planning target volume (PTV) were predictors of RP for both non-surgical group and PORT group. Mean heart dose (MHD) predicted RP in PORT group only (OR = 1.28, p = 0.003). Among patients who developed RP, V20, MLD, and MHD were significantly lower in PORT group than in no-surgical group (p < 0.05 for each comparison).ConclusionsExcept MHD predicting RP in PORT group only, most of predictors for RP were consistent in patients treated with RT with or without surgery. Patients receiving PORT had a higher risk of RP than patients receiving RT without surgery did, possibly due to decreased lung volume and lower tolerance of lung to chemoradiotherapy.