Intensity Modulated Proton Therapy For Head-And-Neck Cancer: The First Clinical Experience

Intensity-modulated radiation therapy (IMXT) results in improved conformality but often produces unacceptable beam-path toxicity (i.e. oral mucositis, nausea and vomiting) from use of multiple coplanar beams for head and neck cancer. We sought to test the feasibility, toxicity, and effectiveness of multi-field optimization (MFO) intensity-modulated proton therapy (IMPT) with discrete spot scanning beam technology for patients with head and neck tumors. Fifteen patients with head and neck cancer [8 oropharynx, 4 nasopharynx, 2 paranasal sinus, and 1 unknown primary], enrolled on an approved protocol, underwent MFO IMPT with a simultaneous integrated boost; 10 had squamous cell carcinoma and 5 had adenoid cystic carcinoma. Doses for patients, who were to receive concurrent chemoradiation therapy, were 70 Gy(RBE), to be given in 33 fractions of 2.12 Gy(RBE). Organs at risk were brain, brainstem, spinal cord, optical apparatus, cochleas, parotids, submandibular glands, oral cavity, larynx, and esophagus. All 15 patients completed treatment with MFO IMPT with no need for treatment breaks and no hospitalizations; 12 patients (80%), 4 of whom had induction chemotherapy, also received concurrent chemotherapy. Toxicity profile was favorable; there were no treatment-related deaths and only 1 grade 4 toxicity (vomiting). Ten patients (67%) experience no anterior oral mucositis with the other five patients experiencing Grade 1. Six patients (40%) experienced no nausea or vomiting (2 with base-of-tongue, 2 tonsil, 1 nasopharynx, and 1 paranasal sinus tumors); 8 had nausea (4 grade 2, 4 grade 3); and 11 patients experienced no vomiting. No patient had disease progression during treatment, and 14 of 15 patients (93%) experienced clinical complete response of the primary and nodal disease. MFO-IMPT is clinically feasible for head and neck cancer with low acute toxicity and excellent clinical response. Proton therapy may represent the next step in the technological advancement of radiation therapy for head and neck cancer.