The impact of microsatellite instability status on the risk of anastomotic leakage after colorectal cancer surgery
Petrus Vinnars, Martin Rutegård, Peter Cashin, Johan Svensson, Ioannis GkekasAbstract
Introduction
Given the inherent inflammatory nature of tumours with microsatellite instability (MSI) and the increased risk of anastomotic leakage in inflammatory states, we investigated whether MSI is associated with leakage in a modern colorectal cancer cohort undergoing anastomotic surgery.
Methods
All adult patients undergoing anastomotic surgery for colorectal cancer in 2021–2024 were identified and data retrieved using the Swedish Colorectal Cancer Registry, with MSI-high or defective mismatch repair status as exposure and anastomotic leakage as outcome. In our primary analyses, the following confounders were included: sex, age, Association of American Anesthesiologists’ grade, body mass index, anastomotic location, intraoperative bleeding and minimally invasive surgery. We also performed analyses using only patients from hospitals with low levels of missing MSI data, as well as stratification analyses according to tumour site. All analyses were carried out using both complete datasets and multiple imputation.
Results
24 011 patients remained after exclusion, of whom 1031 patients (4.29%) suffered from anastomotic leakage. In an unadjusted analysis, MSI was associated with lower odds of anastomotic leakage (OR 0.78, 95% c.i. 0.62–0.97). This association was neither seen overall (OR 1.07, 95% c.i. 0.84–1.38), nor in any strata (OR for right-sided tumours 1.20, 95% c.i. 0.83–1.74), when adjusting for confounders.
Discussion
In our cohort, MSI status was not associated with an increased risk of anastomotic leakage. Although caution is warranted when performing anastomotic surgery in patients with overt signs of inflammation, MSI on its own does not seem to be an important risk factor for leakage.