This study was a multicenter, retrospective cohort study. Although advancements in surgical techniques have mitigated the incidence of intestinal anastomotic fistula, complete avoidance remains elusive. Anastomotic leakage (AL) complications directly impinge on postoperative quality of life and pose life-threatening risks if inadequately managed. Given AL's adverse prognostic implications and the financial strain on patients' families, identifying its risk factors aids in perioperative risk assessment, enabling timely clinical decisions on interventions to enhance prognosis and curtail adverse outcomes and economic investments.

Optimal cytoreduction, particularly in advanced cases, significantly extends 5-year survival compared to cases with residual disease exceeding 1 cm. Consequently, ultra-radical tumor cytoreduction procedures, commonly performed in advanced ovarian cancer, entail the excision of abdominopelvic tissues affected by the primary ovarian malignancy, including segments of the bowel, bladder, spleen, gallbladder, diaphragm, and other organs. Rectosigmoid resection (RSR) emerges as the predominant bowel resection, followed by colon and small bowel resections. Intestinal anastomosis post-RSR is indispensable for bowel reconstruction but bears a notable risk of postoperative anastomotic fistula (AL), a major complication. AL incidence rates fluctuate over time, reported between 8-14% in OC surgery patients undergoing RSR.

AL imposes considerable burdens, encompassing elevated hospital costs, prolonged stays, heightened rates of secondary admissions and surgeries, and mortality rates ranging from 3% to 21%. Furthermore, AL delays the commencement of adjuvant chemotherapy, detrimentally impacting overall survival and representing a significant consequence of colorectal surgery.

Inclusion Criteria:

1. Patients with postoperative pathological diagnosis of primary ovarian, fallopian tube or peritoneal cancer
2. Patients undergoing tumour cytoreductive surgery combined with colorectal resection and stage I intestinal anastomosis
3. No history of other malignant tumours
4. Complete case data

Exclusion Criteria:

1. Previous combination of malignant tumours of other organs
2. Comorbidities with serious diseases related to other organs
3. Patients undergoing secondary tumour cytoreduction

All inpatients undergoing colorectal resection for patients with ovarian, fallopian tube and peritoneal cancer from January 2018 to June 2023 from multiple study centres were selected for the study.