Comprehensive abdominal composition evaluation of rectal cancer patients with anastomotic leakage compared with body mass index-matched controls

BACKGROUND: Anastomotic leakage (AL) is a fatal complication in patients with rectal cancer after undergoing anterior resection. However, the role of abdominal composition in the development of AL has not been studied. AIM: To investigate the relationship between abdominal composition and AL in rectal cancer patients after undergoing anterior resection. METHODS: A retrospective case-matched cohort study was conducted. Complete data for 78 patients with AL were acquired and this cohort was defined as the AL group. The controls were matched for the same sex and body mass index (± 1 kg/m(2)). Parameters related to abdominal composition including visceral fat area (VFA), subcutaneous fat area (SFA), subcutaneous fat thickness (SFT), skeletal muscle area (SMA), skeletal muscle index (SMI), abdominal circumference (AC), anterior to posterior diameter of abdominal cavity (APD), and transverse diameter of abdominal cavity (TD) were evaluated based on computed tomography (CT) images using the following Hounsfield Unit (HU) thresholds: SFA: -190 to -30, SMA: -29 to 150, and VFA: -150 to -20. The significance of abdominal composition-related parameters was quantified using feature importance analysis; an artificial intelligence method was used to evaluate the contribution of each included variable. RESULTS: Two thousand two hundred and thirty-eight rectal cancer patients who underwent anterior resection from 2010 to 2020 in a large academic hospital were investigated. Finally, 156 cases were enrolled in the study. Patients in the AL group showed longer operative time (225.03 ± 55.29 vs 207.17 ± 40.80, P = 0.023), lower levels of preoperative hemoglobin (123.32 ± 21.17 vs 132.60 ±1 6.31, P = 0.003) and albumin (38.34 ± 4.01 vs 40.52 ± 3.97, P = 0.001), larger tumor size (4.07 ± 1.36 vs 2.76 ± 1.28, P < 0.001), and later cancer stage (P < 0.001) compared to the controls. Patients who developed AL exhibited a larger VFA (125.68 ± 73.59 vs 97.03 ± 57.66, P = 0.008) and a smaller APD (77.30 ± 23.23 vs 92.09 ± 26.40, P < 0.001) and TD (22.90 ± 2.23 vs 24.21 ± 2.90, P = 0.002) compared to their matched controls. Feature importance analysis revealed that TD, APD, and VFA were the three most important abdominal composition-related features. CONCLUSION: AL patients have a higher visceral fat content and a narrower abdominal structure compared to matched controls.