What can particle therapy add to the treatment of prostate cancer?

The treatment of prostate cancer with either protons or carbon ions is not a novelty, and several thousands of patients were treated with hadrontherapy in the past decades. The standard treatment approach consisted in two lateral opposed fields for both protons and carbon ions, mostly delivered with scattered beams and using conventional fractionation and hypofractionation for protons and carbon ions, respectively. Similar (RBE-weighted and BED) doses to photon therapy (XRT) have been delivered, with comparable results in terms of both local control and toxicity. The advancements in dose deposition and image guidance of the early '00s that improved the quality of XRT treatments and then allowed for hypofractionation, are being matched with some delay by hadrontherapy in these very years. Pencil beam scanning is now the norm in proton therapy, and volumetric image guidance is being developed in all new hadrontherapy facilities. There is therefore the possibility of truly taking advantage of superior dose distributions of hadrons and safely apply it to innovative treatment protocols, such as an intraprostatic boost and the treatment of larger volume for advanced stage disease. This full integration between the best of technology and new clinical approaches is probably necessary in order to obtain clinical results that are truly superior to the current state of the art of XRT.