Neoadjuvant chemoradiotherapy determines the prognostic impact of anastomotic leakage in advanced rectal cancer

The prognostic impact of anastomotic leakage (AL) in rectal cancer remains uncertain. We investigated the prognostic significance of AL in rectal cancer patients who underwent curative surgery, especially in terms of chemoradiotherapy.A total of 1,818 rectal cancer patients who underwent radical surgery from 2011 to 2015 were retrospectively evaluated. We categorized patients according to AL and compared survival outcomes between the groups before and after matching. In locally advanced rectal cancer patients, we classified patients according to neoadjuvant chemoradiotherapy (nCRT) or adjuvant chemotherapy (aCTx) and analyzed survival outcomes according to AL in each group.Before matching, overall survival (OS) was significantly worse in the AL (+) group compared to the AL (-) group (P = 0.004). In matched patients, there were no differences in disease-free survival (DFS) and OS between groups (P = 0.423 and P = 0.083, respectively). In subgroup analysis for locally advanced rectal cancer, patients were classified as follows: nCRT (+) and aCTx (+) group; nCRT (+) and aCTx (-) group; nCRT (-) and aCTx (+) group; and nCRT (-) and aCTx (-) group. In the nCRT (-) and aCTx (+) group, patients with AL exhibited significantly worse DFS than patients without AL (P = 0.040). In the other 3 groups, there were no differences in DFS according to AL.In locally advanced rectal cancer, AL had an adverse effect on oncologic outcome in patients receiving aCTx without nCRT but not in patients receiving nCRT.