Background: Little is known about the descriptive epidemiology of colorectal adenomas diagnosed in the population.
Aim: To describe time trends in the rate of first diagnosis of colorectal adenomas and estimate the proportion of adenoma-bearing individuals detected over a 24-year period.
Methods: A total of 11,027 patients were first-diagnosed with colorectal adenomas among Côte-d'Or residents (France) between 1976 and 1999. Annual percentage changes were estimated using a Poisson regression model. The proportion of diagnosed adenoma-bearing individuals was estimated using the prevalence of adenomas in an autopsy study performed in the area.
Results: Standardized diagnosis rates were 89.6/100,000 men and 50.3/100,000 women. During the period 1976-1993, diagnosis rates significantly increased with annual percentage changes in men and women of respectively +17.1% and +22.3% for proximal adenomas, +7.5% and +9.1% for distal adenomas and +7.2% and +8.0% for advanced adenomas. Changes were less marked during the period 1994-1999. The estimated proportion of adenoma-bearing individuals diagnosed during the 24-year period was 20.0% in men and 16.0% in women.
Conclusion: Despite a marked increase in the rate of first adenoma diagnosis, the proportion of diagnosed adenoma-bearing individuals seems too low to induce a significant decrease in colorectal cancer incidence.