Particle therapy in head and neck cancer—expanding therapeutic options

The management of head and neck tumors is challenging and requires a multidisciplinary approach. Besides the common histology of squamous cell cancer, other histologies like adenoid cystic carcinoma, mucosal melanoma, and adenocarcinoma are often present. These tumors are radioresistant and need high radiation doses. Photon beam therapy is often limited by the normal tissue tolerance, and particle therapy using protons or carbon ions is a valuable treatment option. Due to their dosimetric advantages, protons enable deposition of high tumor doses, while optimally sparing the surrounding tissue. Carbon ions offer the additional advantage of a higher linear energy transfer (LET) which results in a higher biological effectiveness of tumor cell damage. Therefore, while protons can also be used in sterilizing microscopic disease, carbon ions should be considered in large macroscopic disease, where a significant tumor burden has to be managed.