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 RP 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 RP and received no steroids. V20 (%) 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 V20, 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 V20, total dose, BED, dose per fraction, peripheral dose) were not predictive of RP requiring steroid intake after STI for stage I NSCLC.