Injection of colorectal cancer cells in mesenteric and antimesenteric sides of the colon results in different patterns of metastatic diffusion: an experimental study in rats

This experimental study was designed to investigate the differences in pattern of local growth and diffusion of colorectal cancer cells injected into either mesenteric (M) or antimesenteric (AM) sides of the colon. A total of 1 x 10(6) colonic adenocarcinoma cells (line DHD/K12-TRb) were injected into the cecal wall of BDIX syngeneic male rats at an M or AM site of the colon. At six weeks after injection, all animals were sacrificed and the presence or absence of tumor in the cecum as well as regional metastasis and peritoneal carcinomatosis were determined. Six weeks after injection, macroscopic tumor growth was observed in 27/37 (72%) animals in group M and 21/32 (65%) in group AM (P = 0.98). In group AM, diffuse peritoneal carcinomatosis was present in 19/21 rats (90.4%) versus 3/27 rats (11%) in group M; this difference was statistically significant (P = 0.025). Regional mesenteric lymph nodes were the only location in which tumor was detected in 23/27 rats (85%) in group M versus 2/21 (9.5%) in group AM; this difference too was statistically significant (P = 0.031) The patterns of diffusion of tumors implanted in mesenteric and antimesenteric sites of the colon appear to be different, although the reason for this is not clear.