Despite improvements in surgical technique and postoperative surveillance, colorectal anastomotic leaks and cancer recurrence after pathologically confirmed complete surgical resection remain a significant issue.
Only recently we have begun to acknowledge the importance of microbial organisms and our symbiotic relationship which allows for our survival and health maintenance.
It has been proposed that factors unrelated to the technical characteristics of the anastomosis may contribute to the development of anastomotic leaks. Furthermore, there is evidence demonstrating that anastomotic leaks are associated with increased local recurrence and reduced disease-free survival in patients with colorectal cancer.
One of the factors that has been scarcely investigated is certainly the gut micriobiome. To this regard, some authors have shown in experimental conditions, how microbiota has a strong influence on the healing process of an intestinal anastomosis. Understanding the mechanisms by which the bacterial community of the gut influences intestinal healing and cancer recurrence process could open the door for new preventive and therapeutic approaches. There is an urgent need for appropriate interventions with a deep microbiota analysis to determine both the surgical technical benefits of a proper anastomosis compared with the potential effect of the gut microbes (beneficial vs harmful) on the processes of wound healing, anastomotic leakage reduction and possible cancer recurrence.
Interrogating the intestinal microbiome using next-generation sequencing technology has the potential to directly and indirectly influence cancer outcomes following colonic resection. The aim of this study is to compare the intestinal microbiota of patients who developed anastomotic leaks and/or local cancer recurrence with matched patients with correctly healed colorectal anastomoses without local recurrence.
Anastomotic leak or insufficiency is an unpredictable complication and serious efforts have been made to identify patients at a higher risk of developing one after surgical colorectal procedures. The lack of consensus on possible risk factors in its development is likely due to the absence of well-designed clinical trials analyzing the various probable causes.
Recent large database evaluations and population-based data have led to the identification of strong associations between patient factors, technical aspects and the occurrence of anastomotic leaks in intestinal surgery. Parthasarathy et al. have identified, using the American College of Surgeons National Surgical Quality Improvement Program (ACSNSQIP) database, male sex, smoking, elective rectal cancer surgery, preoperative albumin level 3, diabetes mellitus and urgent surgery for bleeding as strong predictors for anastomotic leaks (1). In this same study, a combination of oral and intravenous antibiotics has been reported as having a possible protective effect against surgical site infections and anastomotic leaks (2). Intestinal microbes have been mentioned in this paper as emerging potential factors in intestinal healing.
Anastomotic leak has intrigued surgeons for decades and endless efforts have been made to prevent it. Despite steady attempts to perfectly understand its pathophysiology, even the most experienced surgeons have not succeeded to eradicate it from their practice. Even with a perfectly conceived intestinal anastomosis with no tension, torsion or ischemia, in healthy patients with no identifiable risk factors that could impair tissue healing, anastomotic leak may still occur. The inconsistency of some elements as being causal factors of this complication has raised serious doubts over our understanding of its entire pathophysiology.
The emergence of the impact of the microbiome as a common denominator in several medical conditions and pathophysiological processes have made it recently the center of attention in certain gastrointestinal pathologies; the bowel being the largest pool of microbiota in the human body.
Thanks to the advancements in microbiota analysis techniques, we aim at conducting in depth analyses of its compostion in humans before and after surgical intervention with the objective of trying to understand the shifts in microbiota composition that perioperative measures induce, allowing to explain their effects on clinical outcomes, namely anastomotic leaks and local cancer recurrence. This research study will allow to generate new evidence on the importance of gut microbiome in colorectal surgery, which is still widely lacking in the scientific literature to date.
REFERENCES
1. Parthasarathy M, Greensmith M, Bowers D, Groot-Wassink T. Risk factors for anastomotic leakage after colorectal resection: a retrospective analysis of 17 518 patients. Colorectal Dis. 2017 Mar;19:288e298.
2. Kawada K, Sakai Y. Preoperative, intraoperative and postoperative risk factors for anastomotic leakage after laparoscopic low anterior resection with double stapling technique anastomosis. World J Gastroenterol. 2016 Jul 7;22: 5718e5727.