Palliative appropriateness criteria: external validation of a new method to evaluate the suitability of palliative radiotherapy fractionation.

This study supports the dual strategy of PRL and risk of early death calculation, with results stratified for fractionation regimen, in line with the original PAC score study. When considering multifraction regimens, the PAC score identifies patients who may benefit from shorter courses. Additional work is needed to answer open questions surrounding the underlying components of the score, because the original and validation study were only partially aligned.