近20年直肠及乙状结肠癌的根治术疗效未见明显进步。早在1914年即开始放射治疗,或为外科切除的辅助治疗,或做为姑息治疗。对于可手术切除的直肠癌综合采用术前放疗,有其确实的放射生物学基础(如腺癌有一定的放射敏感性;有相 The curative effect of radical resection of rectal and sigmoid colon cancer in the past 20 years has not seen obvious progress. Radiation therapy began as early as 1914, or as an adjuvant treatment for surgical resection, or as a palliative treatment. The use of preoperative radiotherapy for the resection of rectal cancer has a solid basis for radiobiology (eg, adenocarcinoma has certain radiosensitivity;