背景与目的:局部复发是Ⅱ～Ⅲ期直肠癌治疗后失败的主要原因.手术联合放化疗被广泛用于局限进展期直肠癌的治疗以提高直肠癌术后的局部控制率.但由于直肠周围正常组织的限制,肿瘤床及区域淋巴结的照射剂量被限制在45～50 Gy,无法进一步提高;且同步放化疗较单纯放疗明显增加了治疗相关毒性,对于中危的PT3No直肠癌是否要采用同步放化疗存在争议.术中放疗采用电子线照射技术,对术后瘤床进行单次大剂量照射,缩短了手术和照射的间隔时间,避免了瘤床周围重要正常组织的不必要照射.本文旨在探讨术中放疗在PT<,3>N<,0>M<,0>直肠癌辅助治疗中的价值.方法:回顾性分析1998年-2005年间接受放射治疗的pT<,3>N<,0>M<,0>期直肠癌74例.所有患者均接受了直肠癌根治手术,联合盆腔淋巴结清扫.其中39例患者接受了手术联合单纯术中放疗(15～25 Gy)及术后化疗.35例患者接受了手术联合术后辅助放化疗[外照射总剂量为(45～50.4)Gy/(25～28)Fx,共5～5.5周].采用SPSS 13.0统计软件进行处理,并采用Kaplan-Meier法进行总生存率、无瘤生存率、局部一区域控制率及无远处转移率分析.结果:中位随访71个月(15.93～127.37个月),术后放疗组1、3和5年局部控制率分别为94%、91%和91%;术中放疗组1、3和5年的局部控制率分别为97%、90%和87%(P=0.939).术后放疗组1、3和5年总生存率分别为100%、91%和85%;术中放疗组1、3和5年总生存率分别为100%、94%和84%(P=0.416).术后放疗组1、3和5年无瘤生存率分别为94%、80%和76%;术中放疗组1、3和5年无瘤生存率分别为97%、82%和74%(P=0.709).术中放疗组3级急性骨髓抑制(P=0.02)及肛周皮肤黏膜反应(P<0.01)发生率明显低于术后放疗组.结论:pT<,3>N<,0>M<,0>直肠癌患者接受术中放疗或术后同期放化疗后的局部控制率、总生存率及无瘤生存率均无明显差异,但术中放疗缩短了手术和放疗时间间隔及疗程,且急性不良反应明显低于术后放疗组.因此,经大样本前瞻性研究结果检验后,术中放疗有望替代常规外放射治疗作为pT<,3>N<,0>M<,0>直肠癌的主要辅助治疗手段之一.%Background and purpose: Local-regional failure was one of the major concern after curative surgery for stage Ⅱ- Ⅲ rectal cancer. Although concurrent chemoradiotherapy has been the standard for locally advanced rectal cancer, the dose of external beam radiotherapy was still limited to 45-50 Gy owing to the tolerance of the surrounding normal tissues, additional escalation of the radiation dose delivered to the tumor bed and regional lymph nodes with conventional radiotherapy was not feasible. Compared to radiotherapy alone, the addition of chemotherapy would further improve the treatment toxicity. Therefore, the role of chemoradiotherapy in patients with inter-median risk, stage Ⅱ A (pT3N0M0) rectal cancer was controversial. Intraoperative radiotherapy (IORT) has the ability to deliver a high, singie-fraction radiation dose to tumor beds with minimal exposure of surrounding tissues (ie small intestine,et al), which are displaced or shielded right after the tumor removal during the surgical procedure. Our aim of this study was to evaluate the efficacy of intraoperative radiation therapy (IORT) followed by adjuvant chemotherapy in the treatment of pT3N0M0 rectal adenocarcinoma. Methods: From 1998 to 2005, 74 consecutive patients with newly diagnosed pT3N0M0 adenocarcinoma of the rectal underwent either Dixon or Miles combined with bilateral lymph node dissection. Thirty-five patients received adjuvant concurrent chemotherapy (5-FU, lencovorin and cisplatin)and external-beam radiation therapy (EBRT), and 39 patients received IORT (dose range: 15-25 Gy) immediately after radical surgery followed by identical systemic chemotherapy (IORT group). Kaplan-Meier method was used to estimate the overall survival, disease-free survival, and local control rates. Results: After a median follow-up of 71 months (range: 15.93-127.73 months), the 5-year locoregional control rates were 91％ in the EBRT group, versus 87％in the IORT group, respectively (P＞0.05). The 5-year overall survival and disease-free survival were 85％ and 76％in the EBRT group versus 84％ and 74％ in the IORT group, respectively (P＞0.05). Compared to EBRT group, the incidence of acute grade 3 toxicity was significantly lower in IORT group (P＜0.05). Conclusion: IORT followed by chemotherapy as an adjuvant treatment for pT3N0M0 rectal adenocarcinoma provided a similar outcome in terms of local control, overall survival, and disease free survival, as compared to concurrent chemoradiation therapy after surgery.However, no significant acute or late complications were observed in patients treated with IORT. Further investigation,preferably in prospective fashion, is warranted to confirm the efficacy of IORT in the treatment of non-metastatic rectal cancer.
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