Current Status and Future Directions of Proton Therapy for Head and Neck Carcinoma

Simple Summary Proton therapy allows for more effective organs at risk avoidance than photon radiotherapy, thus reducing both radiation-induced toxicity and second cancer risk. The aim of the present paper is to compare protons and photons outcomes in the context of oropharyngeal and nasopharyngeal cancer and provide an updated comprehensive overview of the most promising new approaches and methodologies for treating head and neck cancer with protons.Abstract The growing interest in proton therapy (PT) in recent decades is justified by the evidence that protons dose distribution allows maximal dose release at the tumor depth followed by sharp distal dose fall-off. But, in the holistic management of head and neck cancer (HNC), limiting the potential of PT to a mere dosimetric advantage appears reductive. Indeed, the precise targeting of PT may help evaluate the effectiveness of de-escalation strategies, especially for patients with human papillomavirus associated-oropharyngeal cancer (OPC) and nasopharyngeal cancer (NPC). Furthermore, PT could have potentially greater immunogenic effects than conventional photon therapy, possibly enhancing both the radiotherapy (RT) capability to activate anti-tumor immune response and the effectiveness of immunotherapy drugs. Based on these premises, the aim of the present paper is to conduct a narrative review reporting the safety and efficacy of PT compared to photon RT focusing on NPC and OPC. We also provide a snapshot of ongoing clinical trials comparing PT with photon RT for these two clinical scenarios. Finally, we discuss new insights that may further develop clinical research on PT for HNC.