This is a study by the Memorial Sloan Kettering based on the national cancer database. This analysis found that among the 220,491 patients who received any radiation therapy as part of their initial treatment course, only 417 (0.2%) of whom received proton therapy. The use of protons had a small increase from 0.13% in 2005-06 to 0.41% by 2013-14 (P < .001).

The most common primary sites treated with proton therapy were the nasal cavity/nasopharynx and the oral cavity. Most patients had T4 disease. This study concluded that proton use has undergone an incremental increase in the United States but remains an uncommon modality for the treatment of primary head and neck cancer.