Particle therapy in gastrointestinal cancer-a narrative review.

Background and Objective: Radiation therapy is one of the main pillars in the treatment of gastrointestinal (GI) cancers, especially esophageal and anorectal malignancies. The worldwide standard of care is yet an irradiation with photons. Though not commonly used, charged particles offer some physical advantages with a highly conformal dose distribution, which allows an even better sparing of organs at risk. In addition to dosimetric advantages, heavy-ion beams like carbon ions may offer an additional set of biological advantages. Because particle therapy is not standard of care, data are scarce-especially concerning the use in GI malignancies. The aim of this review is to provide a compact overview of the currently available literature. Methods: PubMed and Web of Science databases were searched for publications on particle radiotherapy in GI cancer (e.g., proton therapy in esophageal cancer, carbon ion radiotherapy in pancreatic cancer). Key Content and Findings: Here we present a review of the current data on particle therapy with regard to esophageal, pancreatic, hepatic and anorectal malignancies. Conclusions: Data on particle therapy in GI cancer are scarce. Nevertheless, the current literature shows some promising results. Further clinical evidence, especially randomized trials, is crucial to augment the role of particle radiotherapy in GI cancer.