Bile acid in drainage fluid for early diagnosis of anastomotic leakage and safe discharge after minimally invasive rectal cancer resection: A prospective cohort study.

Background: This study was designed to evaluate the diagnostic value of bile acid levels in drainage fluid for early prediction and exclusion of anastomotic leakage, and assess the performance in allowing a safe discharge.

Methods: This prospective single-center study was conducted in patients diagnosed with rectal cancer who had received minimally invasive anterior resection consecutively from December 2021 to March 2024. Bile acid in drainage fluid, C-reactive protein, and procalcitonin in serum were measured on the third and fifth day after surgery. Four criteria were considered in discharging patients: a C-reactive protein level below 100 mg/L, flatus with or without defecation, a restore of liquid diet, a bile acid level less than 2 μmol/L.

Results: A total of 419 patients were included and divided into an anastomotic leakage group (n = 37; 8.8%) and a nonanastomotic leakage group (n = 382; 91.2%). Of those patients, 384 accorded with the discharge criteria and 380 of them (99%) discharged safely. The rate of anastomotic leakage after discharge and readmission was 0.5% and 0.3%. Bile acid levels in drainage fluid in the anastomotic leakage group were significantly greater than that in the nonanastomotic leakage group on both postoperative days 3 and 5 (postoperative day 3: 3.00 [2.00-5.17] μmol/L vs 0.80 [0.40-1.30] μmol/L, P < .001; and postoperative day 5: 5.17 [3.00-9.20] μmol/L vs 2.00 [1.40-3.50] μmol/L, P < .001). The negative predictive value in ruling out an anastomotic leakage were 0.96 on postoperative day 3 and 0.97 on postoperative day 5 for bile acid alone.

Conclusion: Drainage bile acid has a high negative predictive value in the early diagnosis of anastomotic leakage and showed potential to allow for safe discharge.