Impact of anastomotic leakage on long-term oncologic outcome and its related factors in rectal cancer

Anastomotic leakage (AL) is a well-known cause of morbidity after low anterior resection (LAR) for rectal cancer, but its impact on oncologic outcome is not well understood. The aim of this study is to investigate the impact of AL on long-term oncologic outcome and to identify factors associated with AL that may affect prognosis after LAR for rectal cancer. A retrospective analysis of patients who underwent curative resection for rectal cancer without diverting stoma was performed. To investigate AL related factors that may be associated with oncologic outcome, Clavien-Dindo grades, prognostic nutritional indices (PNI) and inflammatory indices were included. One hundred and one patients out of a total of 1258 patients developed postoperative AL, giving an AL rate of 8.0%. Patients with AL showed poorer disease-free survival (DFS), than patients without AL (hazard ratio [HR] = 1.6; 95% confidence intervals [CI]: 1.1-2.5; P = 0.01). In patients who developed AL, age over 60 (HR = 2.2; 95% CI: 1.1-4.7; P = 0.033), advanced pathologic stage (HR = 2.4; 95% CI: 1.4-4.0; P = 0.001), suppressed neutrophil-proportion (≤80%) (HR = 2.6; 95% CI: 1.2-5.8; P = 0.019) and PNI <36 (HR = 3.5; 95% CI: 1.2-9.6; P = 0.018) were associated with poorer DFS. AL was associated with poorer DFS. In patients with AL, a suppressed neutrophil-proportion and decreased PNI below 36 were associated with tumor recurrence.