Predictors of Rescue Surgery, Mortality, and Permanent Stoma After Anastomotic Leak Following Colorectal Cancer Resection

Anastomotic leakage following colorectal cancer resection is associated with substantial postoperative morbidity and mortality. Although several management strategies are available-including antibiotics, image-guided drainage, endoscopic treatment, transanal drainage, proximal diversion, operative washout, anastomotic revision, and dismantling of the anastomosis-the clinical course varies considerably between patients.

Early identification of patients who are likely to require operative rescue, die following the leak, or remain with a permanent stoma may improve clinical decision-making. However, the predictors of these outcomes have not been sufficiently defined across different colorectal resections, anastomotic levels, leak presentations, and treatment strategies.

This study will include consecutive adult patients with colorectal cancer who develop a confirmed anastomotic leak after colorectal resection with primary anastomosis.

Anastomotic leakage will be defined as a defect in the intestinal wall at the anastomotic site resulting in communication between the intraluminal and extraluminal compartments. The diagnosis may be established clinically, radiologically, endoscopically, or operatively.

For this study, "rescue surgery" means an unplanned operative intervention performed for control or treatment of the anastomotic leak. It may include laparoscopy or laparotomy, abdominal or pelvic washout, operative drainage, anastomotic repair or revision, proximal diversion, or dismantling of the anastomosis with formation of an end stoma.

The decision to perform rescue surgery or any other treatment will remain entirely at the discretion of the treating clinical team. Participation in the study will not alter routine management.

Inclusion criteria

• Age 18 years or older. Histologically confirmed or clinically suspected primary colorectal adenocarcinoma requiring surgical resection.

Undergoing elective or emergency colorectal resection with formation of a primary intestinal or colorectal anastomosis.

Anastomotic leakage diagnosed within 90 days after the index colorectal resection or during the index hospital admission.

Leak confirmed clinically, radiologically, endoscopically, through drainage of enteric contents, or during operative exploration.

Availability of sufficient medical records to determine the method of leak diagnosis, treatment, and short-term outcomes.

Ability to complete follow-up for stoma status, where applicable.

Exclusion criteria

• Age younger than 18 years. Colorectal operation performed for a benign condition without colorectal cancer.

Abdominoperineal excision or another procedure without formation of an intestinal anastomosis.

Local transanal tumour excision without colorectal anastomosis. Leakage involving only a urinary, vascular, or non-intestinal anastomosis. Planned permanent stoma without a colorectal or intestinal anastomosis. Anastomotic leak occurring after surgery for recurrent disease without resection of a primary colorectal tumour, unless specifically included in a predefined secondary cohort.

Inability to verify the diagnosis of anastomotic leakage. Inadequate data to determine all three primary outcomes. Refusal to participate where individual informed consent is required.