局部晚期直肠癌术前短程放疗的研究进展

术前放疗提高了局部晚期直肠癌的局部控制率，可以采用常规分割同步化疗的长程方案，也可行25 Gy／5次短程放疗。前者肿瘤反应率高；后者毒副反应低，耐受性好。二者局部控制率无差异，均好于单独手术，但总生存率未见提高。短程放疗延期4～8周后手术较7天内手术提高了肿瘤反应率。近期研究又发现短程放疗联合新辅助化疗并延期手术，进一步提高了肿瘤的完全缓解率，甚至有超过长程同步放化疗的趋势，局部控制率亦不劣于长程。但是否可降低远处转移率，提高总生存率还有待长期研究。

Progress of preoperative short-course radiotherapy in locally advanced rectal cancer

Preoperative radiotherapy increased local control rates of locally advanced rectal cancer.Short-course radiotherapy (25 Gy/5 f) or conventionally fractionated chemoradiotherapy (long-course radiation) are the most frequent therapies.Long-course radiation with concurrent chemotherapy presents higher tumor response rate.But the benefits of short-course schedule are the lower rate of toxicity and better compliance for patients.There are no differences in local control rate between the two schedules and superior to surgery alone.But overall survival rate has not been improved.Short-course radiotherapy with delayed surgery of a 4-8 weeks' interval increased tumor complete response rate compared with short-course radiotherapy with immediate surgery of within 7-day.More recently,short-course radiotherapy combined with neoadjuvant chemotherapy and delayed surgery has been proposed as a promising regimen,which further improves pathologic complete response rate and even showes a trend toward being superior to long-course chemoradiotherapy,and the local control rate is not inferior to the long-course schedule.Long-term outcomes involved decreasing distant metastasis rate and increasing overall survival rate need further study.