POSSIBLE EFFECT OF PNEUMOPERITONEUM ON THE SPREADING OF COLON-CANCER TUMOR-CELLS

PURPOSE: By using a murine hepatic metastatic model, we tried to inves tigate the possible influence of gas insufflation in colon cancer cell s spreading from the portal system to the liver. METHODS: After transd ucing the human placental ALP gene into murine colon cancer cell line CT26, we successfully selected a clone of CT26/DAP that would yield a specific color following histochemical staining. Fifty mice were assig ned into two groups, receiving either an intrasplenic injection of 10( 6) CT26/DAP cells alone or the cells followed by intra-abdominal heliu m insufflation with the pressure of 15 cm H2O for ten minutes. Five mi ce in each group were used to observe their survival and the other mic e were killed at four different time periods: 10 minutes, 24 hours, 48 hours, and 72 hours following cell injection. The livers and spleens were removed for histochemical staining. By counting the numbers of sp ecific dark reddish spots of CT26/DAP cells, we could estimate the num ber of tumor cells on the hepatic surface. RESULTS: At the very beginn ing following tumor cell injection, we found a significantly greater n umber of tumor cells on the hepatic surface in mice with gas insufflat ion (6354 +/- 1072 vs. 2133 +/- 223, respectively; P = 0.012). But the difference of these two groups became smaller and smaller as time wen t by. The number of tumor cells on the hepatic surface would reach the lowest level at postoperative 48 tours, and the tumor foci then began to grow both in size and number. The above patterns of dynamic change in tumor cell distribution were similar in mice both with and without gas insufflation. Average survival was slightly shorter in mice with gas insufflation, but the difference was not statistically significant . CONCLUSION: Pneumoperitoneum caused by gas insufflation may increase tumor cell spread from the portal system to the liver at the very beg inning stage; however, there was no significant difference in long-ter m survival between mice with and without gas insufflation in this muri ne animal model.