Conventional radiotherapy plan using the same treatment planning computed tomography. The treatment margin was set to give the same dose distribution covering the clinical target volume, compared to proton beam therapy. 100%=2 Gy. Avoiding the spinal cord is difficult and the dose to the lung (V20=46.2%, V30=37.6%, mean lung dose=2213 cGy) is not acceptable with irradiation at the tolerance dose of the spinal cord (50 Gy in 25 fractions) using this treatment plan.