Abstract
Three hundred and twenty-seven patients with inoperable squamous cell carcinomas of the head and neck were entered on a randomized study comparing a mixture of neutron and photon (“mixed beam”) radiation therapy with photon/electron radiation therapy. Neutron treatment was delivered with fixed-beam, physics-laboratory-based equipment. Patients with histologically proven tumors of T-stage T 2, T 3, or T 4 and any N-stage were eligible for randomization. Primary tumor sites were limited to cancers originating in the oral cavity, oropharynx, supraglottic larynx, or hypopharynx. Patients entered on this study now have a minimum at-risk follow-up period of 6 years. Study results reveal no significant differences in overall loco-regional tumor control rates or survival. Subgroup analysis reveals significant differences based on whether or not patients presented with positive lymph nodes. Locoregional tumor control rates for patients presenting with positive lymph nodes were 30% for mixed-beam-treated patients versus 18% for photon-treated patients ( p = 0.05). Loco-regional tumor control rates for patients presenting without positive lymph nodes were 64% for photon-treated patients and 33% for mixed-beam-treated patients ( p = 0.004). Control of tumor located in the nodal sites favored mixed beam over photons by a margin of 45% ( 49 109 ) to 26% ( 23 87 ) with a significance of p = 0.004. Possible explanations for these contradictory findings are discussed.
Published Version
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