2Kawashima M,Kagami Y,Toita T,et al.Prospective trail of radiotherapy for patients 80 years of age or older with squamous cell carcinoma of the thoracic esophagus[J].Int J Radiat Oncol Biol Phys,2006,64(4):1112-1121.
3Abrams J A,Buono D L,Strauss J,et al.Esophagectomy compared with chemoradiation for early stage esophageal cancer in the elderly[J].Cancer,2009,115(21):4924-4933.