Radiation pneumonitis in non.small.cell lung cancer patients treated with helical tomotherapy
Objective: In this study, we investigated the incidence of radiation pneumonitis (RP) in non.small.cell lung cancer (NSCLC) patients undergoing helical tomotherapy (HT) and the clinical and dosimetric factors associated with it.
Materials and Methods: We analyzed data from the treatment protocols of 62 NSCLC patients. The median total radiation dose was 64 Gy (range 57.6.66 Gy) at 22.214.171.124 Gy/fraction. Thirty.four of these patients underwent HT alone and 28 underwent HT in combination with chemotherapy. Treatment.related pneumonitis was graded according to the Common Terminology Criteria for Adverse Events, version 3.0.
Results: We found that RP grades 1, 2, 3 and 5 occurred in 29 (46.8%), 23 (37.1%), 8 (12.9%), and 2 (3.2%) patients, respectively. Using univariate analyses, we found that a grade .3 RP was associated with poor performance status (PS), age, planning target volume, mean lung dose, and relative V5 through V25, in increments of 5 Gy (P < 0.005). We determined that PS and V5V15 were the most significant factors associated with grade .3 RP using multivariate analysis.
Conclusions: We found that poor PS and V5.V15 were the risk factors associated with grade .3 RP in NSCLC patients treated with HT. Thus, for NSCLC patients treated with HT, the volume of total lung with low.dose region (V5.V15) should be carefully regulated and the use of HT should be restricted in patients with Eastern Cooperative Oncology Group .2.
Key words: Helical tomotherapy, non.small.cell lung cancer, radiation pneumonitis