Based on the national cancer database, there were total of 175,088 patients with HNSCC receiving either photon or proton RT. This analysis pointed out that patients receiving proton RT were more likely to be white, reside in higher income areas, and have private insurance. Proton RT was associated with delayed RT initiation compared to photon RT (median 59 days vs. 45, P < 0.001).

Receipt of proton therapy was independently associated with RT initiation beyond 6 weeks after diagnosis or surgery. In the context of adjuvant proton RT, increases in treatment delay were associated with worse overall survival. This study concluded that use of proton therapy is associated with delayed RT in both the definitive and adjuvant settings for patients with HNSCC and could be associated with poorer outcomes.