To what extent should the intestinal be resected proximally after radiotherapy:hint from a pathological view

放疗后直肠癌手术近端肠管应切除多少:病理角度的思考

Background:Neoadjuvant chemoradiotherapy(nCRT)is associated with post-operative anastomotic complications in rectal-cancer patients.Anastomosis involving at least one non-irradiated margin reportedly significantly reduces the risk of post-operative anastomotic complications in radiation enteritis.However,the exact scope of radiotherapy on the remaining sigmoid colon remains unknown.Methods:We evaluated the radiation damage of proximally resected colorectal segments in 44 patients with rectal cancer,who received nCRT followed by conventional resection(nCRT-C,n=21)or proximally extended resection(nCRT-E,n=23).The segments from another 13 patients undergoing neoadjuvant chemotherapy(nCT)were used as control.We dissected these samples at a distance of 2 cmbetween the two adjacent sections.Radiation damage in proximally resected colorectal segments was evaluated using the radiation injury score(RIS)and the concentration and distribution patterns of angiostatin.Results:Compared to those in the nCT group,the nCRT group showed higher RIS,levels of angiostatin,and proportion of diffuse pattern of angiostatin.With increasing distance from the tumor site,these parameters all gradually decreased;and the differences came to be not significant at the site that is over 20cm from the tumor.The nCRT-E group showed lower RIS(median:2 vs 4,P=0.002)and a greater proportion of non-diffuse angiostatin(87%vs 55%,P=0.039)at the proximal margins compared with the nCRT-C group.Conclusions:The severity of the radiation damage of the proximal colon is inversely proportional to the proximal-resection margin length.Little damage was left on the proximal margin that was over 20cm from the tumor.Removal of an initial length of20cm from the tumor may be beneficial for rectal-cancer patients after nCRT.

背景:新辅助化放疗(nCRT)会增加直肠癌患者术后吻合口并发症的发生概率。有报道显示,吻合时至少保证有一端是未被放射损伤的肠管,可降低术后吻合口并发症的发生风险。然而,放疗对残留乙状结肠确切的损伤范围目前尚不明确。方法:我们对44例直肠癌手术标本中近端肠管的放射性损伤情况进行评估,其中21例在nCRT后接受了传统切除术(nCRT-C组),23例在nCRT后接受了近端扩大切除术(nCRT-E组)。另取13例仅接受新辅助化疗(nCT)的直肠癌手术标本作为对照。每隔2 cm对手术标本进行取材。采用放射性损伤评分(RIS)和血管抑素水平及其分布模式,对切除的近端肠管进行放射性损伤评估。结果:与nCT组相比,nCRT组近端肠管的RIS评分更高,血管抑素水平更高,血管抑素呈弥散分布的比例更高。随着距肿瘤距离的增加,上述指标逐渐下降;当距离肿瘤20 cm以远时,上述指标与nCT组肠管的差异已无统计学意义。与nCRT-C组相比,nCRT-E组近切缘中位RIS评分更低(2 vs 4,P=0.002),血管抑素呈非弥散分布的比例更高(87%vs 55%,P=0.039)。结论:直肠癌近切缘的放射性损伤程度与近端肠管切除长度负相关;当近端切除长度超过20 cm时,近切缘基本没有放射性损伤。建议nCRT后直肠癌手术近端肠管至少切除20 cm。