Risk factors and long-term impact of anastomotic leak after colorectal cancer surgery in the elderly: a 5-year follow-up study

Background The elderly population represents an increasing proportion of patients undergoing surgery for colorectal cancer. Their risks and outcomes may differ from the general population. This study aimed to identify risk factors associated with anastomotic leak (AL) and the outcomes related to this complication in elderly patients, using a large retrospective cohort from a high-volume colorectal surgery unit. Methods A retrospective cohort study was conducted including patients aged ≥ 75 years who underwent colorectal cancer surgery between January 2015 and March 2019 at a tertiary centre. Univariable and multivariable logistic regression analyses were used to identify predictors of AL. Kaplan–Meier and Cox regression analyses assessed long-term survival. Results A total of 416 patients (mean age 81.3 ± 4.7 years, 56% male) were included, with AL occurring in 12.26% ( n = 51). Independent predictors of AL included preoperative hypoalbuminemia < 3 g/dL (OR 7.70, p = 0.009), mechanical anastomosis (OR 3.13, p = 0.033), and elevated CRP on postoperative day 3 (OR 1.14 per unit, p < 0.001). Intraoperative drain placement was protective (OR 0.34, p = 0.040). AL was associated with higher major complication rates, prolonged hospital stay, and increased 30-day and 5-year mortality ( p < 0.0001). Discharge to rehabilitation centre or hospital-at-home discharge remained associated with AL (OR 4.57, p = 0.011). Independent predictors of mortality included emergency surgery, AL, ECOG ≥ 2, and Clinical Frailty Scale ≥ 5. Conclusions These findings may support improved preoperative decision-making, patient counselling, and development of strategies to optimise outcomes in high-risk elderly patients.