Disease recurrence after colorectal cancer surgery in the modern era: a population-based study.

Purpose This population-based study determined the cumulative incidence (CI) of local, regional, and distant recurrences, examined metastatic patterns, and identified risk factors for recurrence after curative treatment for CRC. Methods All patients undergoing resection for pathological stage I-III CRC between January 2015 and July 2015 and registered in the Netherlands Cancer Registry were selected (N = 5412). Additional patient record review and data collection on recurrences was conducted by trained administrators in 2019. Three-year CI of recurrence was calculated according to sublocation (right-sided: RCC, left-sided: LCC and rectal cancer: RC) and stage. Cox competing risk regression analyses were used to identify risk factors for recurrence. Results The 3-year CI of recurrence for stage I, II, and III RCC and LCC was 0.03 vs. 0.03, 0.12 vs. 0.16, and 0.31 vs. 0.24, respectively. The 3-year CI of recurrence for stage I, II, and III RC was 0.08, 0.24, and 0.38. Distant metastases were found in 14, 12, and 16% of patients with RCC, LCC, and RC. Multiple site metastases were found often in patients with RCC, LCC, and RC (42 vs. 32 vs. 28%). Risk factors for recurrence in stage I-II CRC were age 65-74 years, pT4 tumor size, and poor tumor differentiation whereas in stage III CRC, these were ASA III, pT4 tumor size, N2, and poor tumor differentiation. Conclusions Recurrence rates in recently treated patients with CRC were lower than reported in the literature and the metastatic pattern and recurrence risks varied between anatomical sublocations.