DIETARY OMEGA-3 FATS REDUCE PROLIFERATION AND TUMOR YIELDS AT COLORECTAL ANASTOMOSIS IN RATS

Background and Aims: Colorectal anastomoses show increased mucosal cry pt cell proliferation rates (CCPRs) and often form the site for tumor recurrence after resection of colorectal cancer. The aim of this study was to assess the effects of a 20% omega-3 fat diet on CCPRs and anas tomotic tumor formation compared with an isocaloric 20% saturated fat diet in experimental colorectal cancer. Methods: One hundred sixty mal e Wistar rats were administered azoxymethane or saline for 6 weeks, af ter which a colonic anastomosis or sham operation was performed. CCPR, mucosal fatty acids, and tumor yield were analyzed at the anastomosis and proximal and distal colon sites at 15 and 23 weeks. Results: Diet , carcinogen treatment, and surgery all had significant effects on CCP R with omega-3 fats producing the lowest CCPR at all sites. There were fewer tumors (P < 0.02), including a marked reduction of anastomotic tumors in omega-3 fat-fed animals that was associated with a significa nt reduction of arachidonic acid in mucosal and tumor lipids. Conclusi ons: Dietary omega-3 fat significantly reduced colonic CCPR and tumor yield, including at the site of anastomosis. Dietary omega-3 fats may be of value to patients after colorectal resection and anastomosis for cancer and warrant further testing.