Relationship between radiation pneumonitis and prognosis in patients with primary lung cancer treated by radiotherapy.

Relationship between the grade of radiation pneumonitis (RP) and treatment outcome in lung cancer patients has not been clarified yet. The purpose of this study was to retrospectively evaluate the relationship in patients with primary lung cancer treated by radiotherapy. One hundred thirty-five patients who underwent definitive radiotherapy with known grade of RP were analyzed. RP was scored by using the Radiation Therapy Oncology Group (RTOG) acute radiation morbidity scoring criteria. Survival and local control data were analyzed in relation to the grade of RP. RP was grade 0 in 5 patients, grade 1 in 71, grade 2 in 39, grade 3 in 15 (11%), grade 4 in 0 and grade 5 in 5 (3.7%). There were no significant correlations between patient or tumor characteristics and grade of RP. Excluding 5 patients with grade 5 pneumonitis, survival rates were similar between those with grade 0 or 1 pneumonitis and those with grade 2 or 3. Also, there was no difference in survival between patients with grade 0-2 pneumonitis and those with grade 3. Local control rates were similar between the two groups. Grade of RP did not appear to be associated with prognosis when patients with grade 5 pneumonitis were excluded from analysis.