Long-term oncologic outcomes associated with clinically significant anastomotic leakage after curative colorectal cancer surgery: Stage- and location-stratified analyses.

BACKGROUND

Clinically significant anastomotic leakage (AL) after colorectal cancer surgery is associated with substantial postoperative morbidity, but its long-term oncologic impact remains uncertain. We evaluated the association of AL with long-term survival, including stage- and location-specific patterns, after curative colorectal cancer surgery.

METHODS

We retrospectively reviewed consecutive patients who underwent curative surgery for non-metastatic colorectal adenocarcinoma between 2004 and 2018. Clinically significant AL was defined as grade B or C leakage. Overall survival (OS) and disease-free survival (DFS) were assessed using Kaplan-Meier and multivariable Cox regression analyses. Subgroup and formal interaction analyses were performed according to tumor stage and location.

RESULTS

Among 2,122 patients, 63 (3.0%) developed clinically significant AL. After multivariable adjustment, including treatment era, AL was not independently associated with OS (HR, 1.581; 95% CI, 0.923-2.707; p = 0.095) or DFS (HR, 1.325; 95% CI, 0.812-2.161; p = 0.260). In stage III disease, patients with AL had lower 5-year OS (56.3% vs. 76.3%; p = 0.005) and DFS (43.9% vs. 68.4%; p = 0.007). However, formal interaction testing showed no significant effect modification by tumor stage (OS, p for interaction = 0.132; DFS, p for interaction = 0.141) or tumor location (OS, p for interaction = 0.775; DFS, p for interaction = 0.748).

CONCLUSIONS

Clinically significant AL was not independently associated with long-term oncologic outcomes in the overall cohort. Although poorer survival was observed in the stage III subgroup, the absence of significant interaction indicates that these stage- and location-specific findings should be interpreted as exploratory rather than evidence of differential AL effects.