Advances in the Technology of Radiation Therapy for Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is highly sensitive to ionizing radiation, and radiation therapy is the mainstay treatment modality for nonmetastatic disease. For decades, NPC radiation therapy utilizes conventional treatment using two-dimentional and lately three-dimentional techniques. Both techniques mainly utilize opposed lateral fields with or without a supplement anterior field focused to the primary tumor to deliver tumoricidal doses of radiation. Disease control using conventional radiotherapy techniques has been acceptable; however, insufficient dose to parts of the targets owing to the proximity of the primary disease to critical structures such as optic chiasm, spinal cord, and/or brainstem may result in reduced disease control in locally advanced NPC. Although the local control of T1 and T2 NPC ranges between 76.6 % and 93 %, the reported overall local control rates were between 58 % and 79 % in patients with locally advanced NPC treated with conventional radiation (Ma et al. 2001; Leung et al. 2005; Au et al. 2003; Chua et al. 2001; Lee et al. 2005).