School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada.
Department of Oncology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Cancer Epidemiology and Prevention Research, Cancer Care Alberta, Alberta Health Services, Calgary, Alberta, Canada.
Cancer Epidemiol. 2024 Oct;92:102640. doi: 10.1016/j.canep.2024.102640. Epub 2024 Aug 5.
Colorectal cancer (CRC) incidence among adults younger than 50 years has increased in recent decades, leading to some advocating for lowering the age to start CRC screening. Here, we estimate age-specific trends in CRC incidence in Canada and changes in risk by birth cohort.
CRC incidence data from 1971 to 2021 by province, sex, and five-year age group (35-64) were obtained from the National Cancer Incidence Reporting System and the Canadian Cancer Registry. Annual percent changes in age-specific or age-adjusted incidence rates were analyzed with joinpoint regression. Birth cohort effect was estimated with age-period-cohort models and reported as cohort incidence rate ratios (IRRs) with respect to the 1947-51 cohort.
CRC incidence has increased among all age groups under 50 years, with the largest relative increases occurring in the youngest age group (35-39 years). Males and females had similar incidence trends, though males under age 50 had larger increases than females. The birth cohort analysis showed that males born since 1966 have a significantly higher risk than those born at any other time.
These results up to 2021 confirm and update reports that CRC incidence is increasing among adults under age 50 in Canada and that the youngest birth cohorts carry the highest risk. Future studies should assess the effectiveness of CRC screening in younger populations.
近几十年来，50 岁以下成年人的结直肠癌（CRC）发病率有所上升，这促使一些人主张降低 CRC 筛查的起始年龄。在此，我们评估了加拿大按年龄划分的 CRC 发病率趋势，并按出生队列变化了风险。
从国家癌症发病率报告系统和加拿大癌症登记处获得了 1971 年至 2021 年按省、性别和 5 岁年龄组（35-64 岁）划分的 CRC 发病率数据。采用 Joinpoint 回归分析年龄特异性或年龄调整发病率的年度百分比变化。利用年龄-时期-队列模型估计出生队列效应，并以相对于 1947-51 队列的队列发病率比（IRR）报告。
50 岁以下所有年龄组的 CRC 发病率均有所上升，其中最年轻年龄组（35-39 岁）的相对增长率最大。男性和女性的发病率趋势相似，但 50 岁以下男性的增长率高于女性。出生队列分析表明，自 1966 年以来出生的男性比任何其他时期出生的男性具有更高的风险。
这些截至 2021 年的结果证实并更新了报告，即加拿大 50 岁以下成年人的 CRC 发病率正在上升，且最年轻的出生队列具有最高的风险。未来的研究应评估在年轻人群中进行 CRC 筛查的效果。
