Comparative evaluation of immune response after laparoscopical and open total mesorectal excisions with anal sphincter preservation in patients with rectal cancer

AIM: The study of immune response of open versus laparoscopical total mesorectal excision with anal sphincter preservation in patients with rectal cancer has not been reported yet. The dissected retroperitoneal area that contacts directly with carbon dioxide is extensive in laparoscopic total mesorectal excision with anal sphincter preservation surgery. Tt is important to clarify whether the immune response of laparoscopic total mesorectal excision with anal sphincter preservation (LTME with ASP) in patients with rectal cancer is suppressed more severely than that of open surgery (OTME with ASP). This study was designed to compare the immune functions after laparoscopic and open total mesorectal excision with anal sphincter preservation for rectal cancer.METHODS: This study involved 45 patients undergoing laparoscopic (n=20) and open (n=25) total mesorectal excisions with anal sphincter preservation for rectal cancer.Serum interleukin-2 (IL-2), interleukin-6 (IL-6), tumor necrosis factor α (TNFα) were assayed preoperatively and on days 1 and 5 postoperatively. CD3+ and CD56+ T lymphocyte count, CD3- and CD56+ natural killer cell (NK)count and immunoglobulin (IgG/IgM/IgA) were assayed preoperatively and on day 5 postoperatively. The numbers of CD3+ and CD56+ T lymphocytes and CD3- and CD56+ NK cells were counted using flow cytometry. An enzyme-linked immunosorbent assay (ELISA) was used for IL-2, TL-6 and TNFα determination. And IgG, IgM, and IgA were assayed using immunonephelometry.RESULTS: The demographic data of the two groups had no difference. The preoperative levels of CD3+ and CD56+ T lymphocyte count, CD3- and CD56+ NK count, serum IgG,IgM, IgA, IL-2, IL-6 and TNFα also had no significant difference in the two groups (P＞0.05). The CD3+ and CD56+ T lymphocyte counts had no obvious changes after surgery in laparoscopic (d=-0.79±3.83 %) and open (d=0.42±2.09 %)groups. The CD3- and CD56+ NK counts were decreased postoperatively in both laparoscopic (d=-7.23±11.33 %) and open (d=-9.21±13.93 %) groups. The differences of the determined values of serum IgG, IgM and IgA on the fifth day after operation subtracted those before operation were -2.56±2.14 g/L, -252.35±392.94 mg/L, -506.15±912.24 mg/L in laparoscopic group, and -1.81±2.10 g/L, -282.72±356.75mg/L, -252.20±396.28 mg/L in open group, respectively. The levels of IL-2 were decreased after operation in both groups.However, the levels of IL-6 were decreased after laparoscopic surgery (d1=-23.14±263.97 ng/L and d5=-40.08±272.03 ng/L),and increased after open surgery (d1=27.38±129.14 ng/L and d5=21.67±234.31 ng/L). The TNFα levels were not elevated after surgery in both groups. There were no significant differences in the numbers of CD3+ and CD56+ T lymphocytes and CD3- and CD56+ NK cells, the levels of IgG, IgM, IgA,IL-2, IL-6 and TNFα between the two groups (P＞0.05).CONCLUSION: There are no differences in immune responses between the patients having laparoscopic total mesorectal excision with anal sphincter preservation and those undergone open surgery for rectal cancer.