Differences in survival and recurrence of colorectal cancer by stage across population-based European registries.

Recurrence after colorectal cancer resection is rarely documented in the general population while a key clinical determinant for patient survival. We identified 8785 patients with colorectal cancer diagnosed between 2010 and 2013 and clinically followed up to 2020 in 15 cancer registries from seven European countries (Bulgaria, Switzerland, Germany, Estonia, France, Italy, and Spain). We estimated world age-standardized net survival using a flexible cumulative excess hazard model. Recurrence rates were calculated for patients with initially resected stage I, II, or III cancer in six countries, using the actuarial survival method. The proportion of nonmetastatic resected colorectal cancers varied from 58.6% to 78.5% according to countries. The overall 5-year net survival by country ranged between 60.8% and 74.5%. The absolute difference between the 5-year survival extremes was 12.8 points for stage II (Bulgaria vs Switzerland), 19.7 points for stage III (Bulgaria vs. Switzerland) and 14.8 points for Stage IV and unresected cases (Bulgaria vs. Switzerland or France). Five-year cumulative rate of recurrence among resected patients with stage I-III was 17.7%. As compared to the mean of the whole cohort, the risk of developing a recurrence did not differ between countries except a lower risk in Italy for both stage I/II and stage III cancers and a higher risk in Spain for stage III. Survival after colorectal cancer differed across the concerned European countries while there were slight differences in recurrence rates. Population-based collection of cancer recurrence information is crucial to enhance efforts for evidence-based management of colorectal cancer follow up.