Identification of Adherence Cut-off Points to the ERAS Protocol: Impact on Survival and Recurrence in Colorectal Cancer Surgery

Background Enhanced Recovery After Surgery (ERAS) programmes shorten recovery after colorectal resection, yet the amount of protocol adherence that translates into long-term oncological benefit is unclear. We explored the impact of different adherence thresholds on overall survival (OS), disease-free survival (DFS) and early morbidity after colorectal cancer surgery. Methods A prospective cohort study was conducted at Hospital Clínico Universitario Lozano Blesa (Zaragoza, Spain). Consecutive adults undergoing elective curative resection for colorectal cancer (September 2011 – February 2013) were analysed. Adherence to a 19-item ERAS pathway (5 pre-, 10 intra- and 4 post-operative elements) was recorded dichotomously; individual patient adherence was expressed as a percentage and stratified into three categories: < 50%, 50–69% and ≥ 70%. Primary outcomes were OS and DFS at 1, 3 and 5 years. Secondary outcomes were 30-day complications and length of stay (LOS). Kaplan–Meier curves, log-rank tests and Cox regression (adjusted for age, sex, comorbidity and AJCC stage) were applied. Results The study included 147 patients (57% male, mean age 70.5 ± 10.2 years). Median adherence was 47.4% (IQR 42.1–63.2); only 15.6% achieved ≥ 70%. Five-year OS was 76% for the whole cohort and did not differ between patients with ≥ 70% versus < 70% adherence (HR 1.21; 95% CI 0.50–2.94; p = 0.673). However, adherence < 45% independently predicted early mortality (≤ 12 months; HR 5.70; 95% CI 1.11–29.4; p = 0.038). Adherence ≥ 50% reduced the risk of recurrence at 5 years (HR 0.34; 95% CI 0.16–0.72; p = 0.006) and 3 years (HR 0.39; 95% CI 0.18–0.90; p = 0.024). Global complication rates fell from 61% (< 50% adherence) to 35% (≥ 70%; p = 0.04), with significant reductions in superficial surgical-site infection and reoperation. Median LOS decreased from 9 to 7 days among patients with ≥ 70% adherence (p < 0.01). Conclusions In this ERAS cohort, an adherence threshold of ~ 50% was associated with superior DFS and fewer recurrences, while very low adherence (< 45%) predicted early death. These findings suggest a minimum ‘effective dose’ of ERAS and support targeted strategies to lift low-performing elements rather than striving solely for perfect compliance