BACKGROUND: Anastomotic leakage might be directly or indirectly related to the prognosis of patients with rectal cancer. OBJECTIVE: This study aimed to investigate whether anastomotic leakage affects the oncologic outcomes in patients with rectal cancer. DESIGN: This was a retrospective analysis of prospectively collected data. SETTINGS: This study was conducted at a teaching hospital between January 2009 and December 2013. PATIENTS: Patients who underwent curative resection for primary rectal cancer were included. MAIN OUTCOME AND MEASURE: Kaplan–Meier analyses were used to evaluate disease-free survival and overall survival. RESULTS: The overall incidence of anastomotic leakage was 2.7% (107/3865). Local recurrence was more frequent in patients with anastomotic leakage than in those without (14.0% vs 6.7%; p = 0.007). By multivariate analysis, anastomotic leakage was associated with increased local recurrence rate ( p = 0.014) and poorer overall survival ( p = 0.011). In subgroup analysis, compared with other pathologic risk factors, anastomotic leakage was associated with higher occurrence of local and distant recurrence in patients with stage II rectal cancer ( p = 0.031 and <0.001). In patients with stage III rectal cancers, adjuvant therapy was more likely to be delayed or canceled in those experiencing anastomotic leakage (63 vs 39 d, p < 0.001; 37.3% vs 66.7%, p < 0.001). In addition, this patient group had the worst survival outcome when compared with those without anastomotic leakage and those with timely adjuvant therapy (5-year disease-free survival rate, p = 0.013; 5-year overall survival rate, p = 0.001). LIMITATIONS: This study is limited by its retrospective nature. CONCLUSIONS: There was a robust association between anastomotic leakage and local recurrence, while also potentially affect long-term survival of the patient group. Delayed or cancelled adjuvant therapy administration because of anastomotic leakage may partly account for the poorer survival in those patients with advanced rectal cancer. See Video Abstract at http://links.lww.com/DCR/B459 . EFECTOS DE OBSERVANCIA DE TERAPIA ADYUVANTE Y FUGA ANASTOMÓTICA, EN RESULTADOS ONCOLÓGICOS DE PACIENTES CON CÁNCER RECTAL, DESPUÉS DE UNA RESECCIÓN CURATIVA ANTECEDENTES: La fuga anastomótica podría estar relacionada directa o indirectamente, con el pronóstico de los pacientes con cáncer de recto. OBJETIVO: El estudio tuvo como objetivo investigar si la fuga anastomótica afecta...