Dosimetric factors predicting radiation pneumonitis after CyberKnife stereotactic body radiotherapy for peripheral lung cancer.

The incidence of symptomatic RP after CyberKnife SBRT was almost identical to the incidences reported in the linear accelerator-based SBRT. A significant association was observed between a V25 >3.4% and the risk of developing symptomatic RP. Advances in knowledge: This is the first report that has investigated prognostic factors for symptomatic RP after CyberKnife SBRT for lung cancer. The newly developed scoring system may help to predict symptomatic RP.