Trends in incidence, treatment, and relative survival of colorectal cancer in the Netherlands between 2000 and 2021

Background The epidemiology of colorectal cancer (CRC) has changed rapidly over the years. The aim of this study was to assess the trends in incidence, treatment, and relative survival (RS) of patients diagnosed with CRC in the Netherlands between 2000-2021. Patients and Methods 275,667 patients diagnosed with CRC between 2000-2021 were included from the Netherlands Cancer Registry. Analyses were stratified for disease extent (localised: T1-3N0M0; regional: T4N0M0/T1-4N1-2M0; distant: T1-4N0-2M1) and localisation (colon; rectum). Trends were assessed with joinpoint regression. Results CRC incidence increased until the mid-2010s but decreased strongly thereafter to rates comparable with the early 2000s. Amongst other trend changes, local excision rates increased for patients with localised colon (2021: 13.6%) and rectal cancer (2021: 34.9%). Moreover, primary tumour resection became less common in patients with distant colon (2000-2021: 60.9%-12.5%) or rectal cancer (2000-2021: 47.8%-6.9%), while local treatment of metastases rates increased. Five-year RS improved continuously for localised and regional colon (97.7% and 72.0% in 2017, respectively) and rectal cancer (95.2% and 76.3% in 2017, respectively). The rate of anti-cancer treatments decreased in distant colon (2010-2021: 80.3% to 67.2%; p<0.001) and rectal cancer (2011-2021: 86.0% to 77.0%; p<0.001). The improvement of five-year RS stagnated for distant colon (2010-2017: 11.2% to 11.9%; average percentage of change [APC]: 2.1, 95% confidence interval [CI]: -7.6, 4.7) and rectal cancer (2009-2017: 12.7% to 15.6%; APC: 1.4, 95% CI: -19.1, 5.5). Conclusions Major changes in the incidence and treatment of CRC between 2000 and 2021 were identified and quantified. Five-year RS increased continuously for patients with localised and regional CRC, but stagnated for patients with distant CRC, likely caused by decreased rates of anti-cancer treatment in this group.