Prevention of anastomotic tumour take by on-table colon washout with povidone-iodine - An experimental study in rats

The presence of organic material in the intestinal lumen is reported to int erfere with the efficacy of cancericidals when used in low concentrations t o prevent anastomotic recurrence in colorectal cancer surgery. We aimed at investigating the efficacy of intra-operative whole-colon washout using pov idone-iodine in an experimental model of anastomotic tumour growth. A large inoculum of highly 'tumorigenic' carcinoma cells was instilled in the colo nic lumen of Fischer rats. The whole-colon water washout was intended to re move the luminal organic material. This was followed by irrigation of incre asing concentrations of povidone-iodine up to 5% with or without additional incubation for 10-20 min. Five animals died after 30 min incubation with p ovidone-iodine 5%. Tumour take was observed in all control animals includin g after irrigation with physiological saline. Increasing the povidone-iodin e concentration from 1 to 5% reduced the rate of tumour take, but not signi ficantly. The anastomotic tumour growth was significantly reduced after tum our cell inoculation followed by whole-colon ravage and luminal incubation for 20 min with povidone-iodine 5%. Application of intra-operative whole-co lon washout to remove the luminal 'organic material' followed by luminal ap plication of povidone-iodine 5% for a sufficient incubation time could redu ce the risk of anastomotic recurrence in colorectal cancer surgery.