RADIATION PNEUMONITIS FOLLOWING COMBINED-MODALITY THERAPY FOR LUNG-CANCER - ANALYSIS OF PROGNOSTIC FACTORS

Purpose: To identify factors associated with radiation pneumonitis (RP ) resulting from combined modality therapy (CMT) for lung cancer. Mate rials and Methods: Series published before 1994 that used CMT for the treatment of lung cancer and explicitly reported the incidence of RP a re the basis for this analysis. Factors evaluated included the radiati on dose per fraction (Fx), total radiation dose, fractionation scheme (split v continuous), type of chemotherapy and intended dose-intensity , overall treatment time, histology (small-cell lung cancer [SCLC] v n on-smell-cell lung cancer [NSCLC]), and treatment schedule (concurrent v induction, sequential, or alternating CMT). Results: Twenty-four se ries, including 27 treatment groups and 1,911 assessable patients, met our criteria for inclusion in this analysis. The median total dose of radiation used in the trials analyzed was 50 Gy (range, 25 to 63 Gy). The median daily Fx used was 2.0 Gy (range, 1.5 to 4.0 Gy). Nineteen series included 22 treatment groups and 1,745 patients treated with si ngle daily fractions. Among these patients, 136 received a daily Fx gr eeter than 2.67 Gy. Five series used twice-daily radiotherapy and incl uded 166 patients (Fx, 1.5 to 1.7 Gy). The incidence of RP was 7.8%. I n a multivariate analysis, only daily Fx, number of daily fractions, a nd total dose were associated with the risk of RP (P < .0001, P < .018 , and P < .003, respectively). Conclusion: In this analysis, the use o f Fx greater than 2.67 Gy was the most significant factor associated w ith an increased risk of RP. High total dose also appears to be associ ated with an increased risk, but twice-daily irradiation seems to redu ce the risk expected if the same total daily dose is given as a single fraction. High-Fx radiotherapy should be avoided in patients who rece ive CMT with curative intent. (C) 1995 by American Society of Clinical Oncology.