Characteristics of patients who developed radiation pneumonitis requiring steroid therapy after stereotactic irradiation for lung tumors

BACKGROUND To find possible risk factors for symptomatic radiation pneumonitis (RP) after stereotactic irradiation (STI) for peripheral non-small cell lung cancer (NSCLC), pre-treatment pulmonary function test and dose volume statistics in patients who developed RIP requiring steroid intake were retrospectively compared with statistics of those who did not develop RP. MATERIALS AND METHODS From 1996 to 2002, 156 patients with Stage I NSCLC received STI at 5 hospitals in Japan. Of those patients, 12 were medicated with steroids for RP after treatment (RP group). For comparison, 31 patients were randomly selected from the remaining 144 patients who received STI but did not receive steroids (control group). RESULTS There were no statistical differences in age, sex, tumor size, performance status, forced expiratory volume in 1 sec(FEV1.0%), or percent vital capacity (%VC) between patients medicated with steroids for RP and those who did not have RIP and received no steroids. V-20 (%) was 7 to 18% (median 8%) in patients medicated with steroids for RP and 2 to 16% (median 7%) in those who did not have RP No difference was observed in V-20, the biologically effectively dose (BED) at the periphery of the planning target volume, or the dose per fraction between the two groups. CONCLUSIONS Pre-treatment pulmonary function test (%VC, FEV1.0%), and dose volume statistics (V-20, total dose. BED, dose per fraction, peripheral dose) were not predictive of RP requiring steroid intake after STI for stage I NSCLC.