대한대장항문학회

Purpose : Preoperative chemoradiotherapy has become an important adjunct in the<br>management of rectal cancer. But both systemic toxicity of chemotherapy and local effect of<br>radiation interfere wound healing of intestinal anastomosis and ultimately may lead to<br>anastomotic leak and septic complications. The purpose of this study is to determine the<br>optimal time interval between preoperative chemoradiotherapy and anastmotic construction,<br>and it was evaluated by security of anastomotic construction. Methods : One hundred and<br>twenty male Sprague Dawley rats weighing approximately 250 g were randomly divided into<br>4 groups (Control group; n=40, Group 1; n=20, Group 2; n=20, Group 3; n=40). The control<br>group (n=20) underwent anastomotic construction at 1 week after general anesthesia without<br>preoperative chemoradiotherapy. The experimental animals (group 1, 2, 3) received<br>preoperative chemoradiotherapy with 5 daily dose (20 mg/kg) of 5-fluorouracil and single<br>dose of 1500 cGy radiation at the rectosigmoid junction under general anesthesia on the day<br>after last dose of chemotherapy. And group 1∼3 subsequently underwent a laparotomy to<br>make anastomotic construction at 1 week (Group 1), 2 weeks (Group 2), and 3 weeks (Group<br>3; n=20) after completion of chemoradiotherapy. The security of anastomotic construction was<br>determined by bursting pressure, tissue hydroxyproline content, gross and microscopic<br>findings of anastomotic area at the 5th and 10th postoperative day after anastomotic<br>construction. To evaluate systemic toxicity after chemoradiotherapy, serial body weight and<br>alteration of CBC were measured in the control group (n=20) and Group 3 (n=20) without<br>anastomotic construction. Results : At the 5th postoperative day, Mean bursting pressures of<br>the all treated groups were lower than that of the control group (Control group; 88 23<br>mmHg, Group 1; 49 22 mmHg, Group 2; 56 17 mmHg, Group 3; 78 23 mmHg). The<br>difference was not significant in the group 3 compared with the control group. Body weight<br>decreased in the all treated animals. The mean body weight was lowest on the day 8 after<br>completion of chemoradiotherapy and then it gradually increased. WBC and platelet counts<br>also decreased in the all treated animals. WBC count was lowest on the day 1 and platelet<br>count was lowest on the day 3 after completion of chemoradiotherapy. Mean hydroxyproline<br>contents at the anastomotic sites in the all treated groups were higher than that of the control<br>group, especially in the group 2 and 3. Similar histologic changes were observed in both<br>group 3 and control group. Conclusion : The results suggest that the optimal time interval for<br>safe intestinal anastomosis after preoperative chemoradiotherapy is 3 weeks or later.<br>