Particle-beam radiation therapy for the tumor of pharyngeal region

Abstract

The purpose of this study is to investigate the treatment result for patient with pharyngeal region and to evaluate the difference between proton (PRT) and carbon ion radiotherapy (CRT). Thirty-three patients, 18 male and 15 female aged from 16 to 81 years underwent at the Hyogo Ion Beam Medical Center between May 2001 and August 2008. Twenty-two patients with nasopharyngeal and 11 with oropharyngeal cancer received PRT for a total prescribed doses of 65 GyE/26 Fr/5.2 weeks (2.5 GyE/ Fr) or CRT for 57.6 GyE/16 Fr/3.2 weeks (3.6 GyE/ Fr). The histology was adenoid cystic carcinoma in 17, squamous cell carcinoma in 6, malignant melanoma in 3, adenocarcinoma in 2, mucoepidermoid carcinoma in 2, and others in 3. The UICC TNM classification was T1 in 4, T2 in 9, T3 in 5, and T4 in 15, and N0 in 29, N1 in 3, and N2 in 1. One case diagnosed as M1 was nasopharyngeal adenoid cystic carcinoma accompanied by multiple lung metastasis. The tumor response was CR in 2, PR in 12, and NC in 14, with a response rate of 50%. The overall 3- and 5-year survival rates were 62 and 62% in all patients, respectively, and 81 and 81% in those with nasopharyngeal cancer. In contrast, none of patients with oropharyngeal cancer survived for 3 years. The 3- and 5-year local control rates were 79 and 79% in all patients, 84 and 84%, in patients with nasopharyngeal cancer, respectively, but slightly poor in those with oropharyngeal cancer, with 1- and 2-local control rates of 89 and 67%, respectively. There was no significant difference between the numbers of patients who underwent proton and carbon ion radiations. The differential use of proton and carbon ion radiation therapies is an unknown, and comparative studies are necessary.