[Analysis of risk factors for long-term severe anastomotic complications following rectal cancer surgery].

Objective: To investigate the risk factors of long-term (>3 months) severe anastomotic complications after rectal cancer surgery. Methods: A case-control study was employed, with the following inclusion criteria for cases: (1) age between 18 and 80 years; (2) history of radical surgery for rectal cancer; (3) tumor located ≤10 cm from the anal verge; (4) occurrence of long-term (>3 months) severe anastomotic complications (e.g., refractory local infection or intestinal obstruction) requiring transverse colostomy; (5) complete clinical data. Exclusion criteria: (1) transverse colostomy due to local recurrence or extensive peritoneal metastasis; (2) transverse colostomy due to non-anastomotic complications(e.g., radiation enteritis, fecal incontinence, anal pain); (3) extensive liver or lung metastasis; (4) loss to follow-up.

This study defined long-term severe anastomotic complications as complications requiring readmission for transverse colostomy, including anastomotic leakage, sinus tract formation, anastomotic stenosis, and intestinal obstruction. According to the above criteria, a retrospective collection was conducted on 107 patients who underwent transverse colostomy after rectal cancer surgery at Shanghai Changhai Hospital from May 2014 to June 2024 due to long-term severe anastomotic complications (severe anastomotic complications group). 737 patients who underwent radical surgery for rectal cancer at the same hospital from January 2019 to December 2019 were selected from the clinical database as the control group. The inclusion criteria for the control group are as follows: (1) age between 18 and 80 years; (2) history of radical surgery for rectal cancer in our hospital; (3)tumor located ≤10 cm from the anal verge; (4) complete clinical data. No transverse colostomy, recurrence, metastasis, death, or loss to follow-up were included.

The observation indicators of this study were risk factors associated with long-term severe anastomotic complications. The variables analyzed included: gender, age, carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), body mass index (BMI), preoperative hemoglobin, preoperative albumin, tumor distance from the anal verge, stoma construction status, postoperative tumor T stage, postoperative tumor N stage, maximum tumor diameter, KRAS mutation, NRAS mutation, BRAF mutation, neoadjuvant chemoradiotherapy status, adjuvant chemoradiotherapy status, and perirectal fat space (PFS).

Preoperative images with fat quantification sequences of the rectum were acquired via the Picture Archiving and Communication System (PACS), followed by quantification of perirectal fat areas at superior and inferior tumor margins using ImageJ software. Results: Among 107 rectal cancer patients undergoing transverse colostomy for long-term severe anastomotic complications, 85 were male (79.4%) and 22 female (20.6%), with BMI (22.3±3.1) kg/m². Twenty-nine patients (27.1%) had no radiotherapy exposure, while 78 (72.9%) received radiotherapy, including 31 (39.7%) preoperatively and 47 (60.3%) postoperatively. The long-term severe anastomotic complications comprised two categories:(1) fistulas in 47 cases (43.9%): including anastomotic, rectovaginal, rectourethral, and rectovesical fistulas; (2) anastomotic stenosis in 60 cases (56.1%). Univariate analysis demonstrated significantly higher proportions of male patients, advanced age, postoperative T/N stages, and radiotherapy history, but lower BMI in the severe anastomotic complications group versus controls (all P