Short- and long-term results after laparoscopic vs conventional colon resection in a tumor-bearing small animal model

Background: We designed a study to evaluate the short- and long-term outcom e of laparoscopic vs conventional colonic resection in a tumor-bearing smal l animal model. Methods: We operated on male BD X rats (260-300 g), performing either lapar oscopic (n = 9) or open colon resection(n = 9) in order to evaluate stress and immunological response to laparoscopic vs conventional colon resection. A third group (n = 9) underwent anesthesia only. Immediately before and af ter surgery, as well as at 1, 7, and 21 days postoperatively, a sample of 1 mi blood was taken from the retrobulbar venous plexus. Stress (corticoster one) and immune parameters (neopterine and IL-1 beta, IL-6) and body weight as a parameter of postoperative recovery were measured to identify short-t erm alterations. Long-term changes were evaluated in terms of survival time and at autopsy by measuring the tumor weight and the number of tumor infil trated nodules (histology). Results: The analysis of variance (ANOVA) showed significant differences be tween the three groups over a period of 1 week (p < 0.001 for corticosteron e, p = 0.009 for neopterine, p = 0.04 for IL-1 beta, p = 0.024 for IL-6). A dditionally, significant differences by t-test were found between the lapar oscopic (minor alteration) and conventional (major alteration) group regard ing corticosterone (p = 0.0015), neopterine (p = 0.0024), IL 1-beta (p = 0. 033), and IL-6 (p = 0.015) at the end of the operation. One week after the operation, the body weight was different depending on the type of operative procedure: 7 days postoperatively the rats lost 8% of their body weight af ter open surgery but only 4.3% after laparoscopic surgery. After anesthesia only, body weight increased by similar to 4.8%. The medium survival time f or the lap group was 44 days, whereas it was 44.1 days for the conventional group and 46 days for the anesthesia group (ANOVA p = 0.625). The number o f nodules was 13.5 in the laparoscopic group 10.5 in the open group, and 7. 4 in the anesthesia group, (ANOVA p = 0.119). The tumor weight was 6.8 g in the laparoscopic group, 6.4 g in the open group, and 5.04 g in the anesthe sia group (ANOVA p = 0.874). Conclusion: In a tumor-bearing small animal model, laparoscopic colon resec tion alters the stress and immune system less than open colon resection. Th is observation has no implications for the long-term results as measured by survival time and at autopsy. Therefore, laparoscopic colon resection has a short-term benefit and has no negative effect on long-term results compar ed to conventional operative procedures.