Suture technique affects perianastomotic colonic crypt cell production and tumour formation

Abstract

Suture line recurrence is an important cause of failure after potentially curative resection for colonic carcinoma. Our aim was to determine whether suture technique affected the incidence of perianastomotic tumours in experimentally induced colonic cancer. Sprague-Dawley rats were randomized into three groups. A 1 cm longitudinal colotomy was repaired with four interrupted 6/0 polypropylene monofilament sutures, using either a transmural technique (n = 18) or a seromuscular technique (n = 18). Control animals (n = 18) had a sham laparotomy. All animals received nine, weekly, subcutaneous injections of azoxymethane (total dose 90 mg/kg) starting 6 weeks after laparotomy. Surviving animals were killed 32 weeks after laparotomy. Five animals from each group were given intraperitoneal bromodeoxyuridine (100 mg/kg) 1 h before being killed. At death, perianastomotic tumours occurred more frequently in animals with transmural sutures than in either controls or those with seromuscular sutures. This difference was associated with a greater mucosal bromodeoxyuridine crypt cell labelling index in the transmural suture group. We conclude that a transmural anastomotic suture technique promotes the development of experimental perianastomotic colonic tumours.

The Influence of the Interaction of Sutures with the Mucosa on Tumour Formation at Colonic Anastomoses in Rats

“…This might be explained by the fact that sig nificantly more tumours develop sponta neously in the descending colon after azoxy methane administration than in the ascend ing colon, so that a relatively weak cocarcinogenic factor will have less opportunity to express itself in a region of high tumour yield. In this study, as indeed in others [2,4,6,13. 27], a significantly higher tumour formation was noted in the left colon when compared to the right colon in the three groups studied (steel, Vicryl and controls) just as for the num ber of anastomotic tumours per rat.…”

“…Other au thors also have noticed an elimination of steel wire sutures [12]. O'Donell et al [4] interest ingly specified that 38 weeks postoperatively. only 5 of 72 transmural sutures remained, while in contrast 59 of 60 seromuscular su tures were identified at the end of the experi ment.…”

“…An interesting study by O'Donell et al [4] showed a higher tumour yield in rats in which a colotomv was closed with transmural sutures as compared to a group in which seromuscular sutures were employed. Various types of suture material have been compared and most studies have shown that non-absorbable sutures (steel) are especially prone to the development of anastomotic tu mours [ 12,25], Only McGregor et al [ 14. 26] observed a lower tumour yield at a steelsutured anastomosis compared to groups in which the anastomosis was carried out with other materials (nylon.…”

“…More and more evidence is now accumu lating that sutures themselves may enhance tumour formation at an anastomosis, over and above that caused by the healing wound itself [3,4], Classical experiments by Pozharisski [23] have shown that the chronic, irri tating effect of suture material caused en hanced tumour formation in the caecum after the administration of dimethylhydrazine, a chemical carcinogen. Calderisi and Freeman [24] implanted various sorts of suture mate rial without creating an actual anastomosis and also noted an enhanced tumour yield at the site at which non-absorbed or slowly ab sorbed suture material had been implanted.…”

“…However, other mechanisms may be responsible for the development of anastomotic recurrence: im plantation of viable, exfoliated colon carci noma cells at the suture line and metachronous carcinogenesis in those recurrences occurring 2 or more years after the primary intervention [1], In metachronous carcinogenesis, the in tensity of cell proliferation at the suture line seems to be the crucial determinant of the risk of malignant change in the epithelium [2], Evidence is accumulating that sutures themselves can enhance tumour formation at an anastomosis over and above that caused by wound healing itself [3,4], In a study on the effect of suture material on colonic anasto motic crypt cell proliferation rate (CCPR) in the rat, we showed that the CCPR of an 8-week-old anastomosis was significantly ele vated when non-absorbable steel suture mate rial was used, whereas no rise in CCPR could be detected when the anastomosis had been carried out with rapidly absorbable suture material (Vicryl Rapide®) [5], In order to explore the respective roles of wound healing and suture material on meta chronous carcinogenesis, we studied the tu mour yield at colonic anastomoses after ad ministration of a chemical carcinogen (azoxymethane) at the moment that in one group of rats suture material was still present and the crypt cell proliferation elevated, while in another group no more suture material was present and the crypt cell proliferation rate normalized at the anastomotic site. As the right and left colon are known to react differ ently to carcinogenic stimuli in both man and animals, the colonic anastomoses were car ried out simultaneously in both the right and left colon of the same animal [6.…”