The impact of anastomotic leak on long-term oncological outcomes after low anterior resection for mid-low rectal cancer: extended follow-up of a randomised controlled trial

Purpose: The impact of anastomotic leaks (AL) on oncological outcomes after low anterior resection for mid-low rectal cancer is still debated. The aim of this study was to evaluate overall survival (OS), disease-free survival (DFS), and local and distant recurrence in patients with AL following low anterior resection. Methods: This is an extension of a multicentre RCT (NCT01110798). Kaplan–Meier method and the log-rank test were used to estimate and compare the 3-, 5-, and 10-year OS and DFS, and local and distant recurrence in patients with and without AL. Predictors of OS and DFS were evaluated using the Cox regression analysis as secondary aim. Results: Follow-up was available for 311 patients. Of them, 252 (81.0%) underwent neoadjuvant chemoradiotherapy and 138 (44.3%) adjuvant therapy. AL occurred in 63 (20.3%) patients. At a mean follow-up of 69.5 ± 31.9 months, 23 (7.4%) patients experienced local recurrence and 49 (15.8%) distant recurrence. The 3-, 5-, and 10-year OS and DFS were 89.2%, 85.3%, and 70.2%; and 80.7%, 75.1%, and 63.5% in patients with AL, and 88.9%, 79.8% and 72.3%; and 83.7, 74.2 and 62.8%, respectively in patients without (p = 0.89 and p = 0.84, respectively). At multivariable analysis, AL was not an independent predictor of OS (HR 0.65, 95%CI 0.34–1.28) and DFS (HR 0.70, 95%CI 0.39–1.25), whereas positive circumferential resection margins and pathological stage impaired both. Conclusions: In the context of modern multimodal rectal cancer treatment, AL does not affect long-term OS, DFS, and local and distant recurrence in patients with mid-low rectal cancer.