Response

Extract

We appreciate the comments of Schild et al. and the opportunity to respond. They raise three concerns: that patients who underwent proton radiotherapy (PRT) for prostate cancer also underwent photon radiotherapy and that the toxicity attributed to PRT may actually reflect photon therapy; that some recorded toxicities were unrelated to radiotherapy; and that the less severe and more common side effects of radiotherapy, such as irritative bladder symptoms and rectal voiding, were not included.

Regarding their first concern, only less than3.2% of patients in the 12-month sample who underwent PRT received photon therapy. The lack of difference in complications between PRT and IMRT in our study is unlikely to be due to this small subset of patients.

Regarding their second concern, in order to measure the toxicity of treatment in the most comprehensive manner possible, we a priori included all Medicare claims indicative of complications potentially due to radiotherapy. Though Schild et al. question whether some of these complications are truly related to radiotherapy, this should not bias our results, as it is unlikely that there would be differential ascertainment of these outcomes between treatment groups.