Department of Oncology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.
JAMA Netw Open. 2019 Jul 3;2(7):e198090. doi: 10.1001/jamanetworkopen.2019.8090.
Recent evidence has shown that although the incidence of colorectal cancer (CRC) is decreasing among older adults, rates have increased in adults younger than 50 years. Given that younger adults are typically classified as at low risk for the disease, this epidemiologic shift is cause for concern.
To analyze Canadian national cancer incidence registries to determine incidence trends for CRC among older and younger adults, updated to 2015.
DESIGN, SETTING, AND PARTICIPANTS: This cohort study determined the incidence of CRC using data from the National Cancer Incidence Reporting System (1969-1992) and the Canadian Cancer Registry (1992-2015). All Canadians diagnosed with CRC from January 1, 1969, through December 31, 2015, were included in this study. Trends among men and women were examined separately and by age category (>50 vs <50 years). Birth cohort models were fit using 5-year groups starting in 1886, with 1936 as the reference cohort. Data were analyzed from May 13, 2018 to May 16, 2018.
Annualized percentage changes and incidence rate ratios of CRC.
From 1971 to 2015, 688 515 incident cases (52.9% women) of CRC were identified. Although the incidence of CRC has decreased in older men and women, rates among younger men and women have increased since 2006 and 2010, respectively. For women younger than 50 years, incidence has increased with a mean annual percentage change of 4.45% since 2010; for men younger than 50 years, a mean annual percentage change of 3.47% from 2006 through 2015. There was an association between CRC incidence and birth cohort, with more recent cohorts being at greater risk than those born earlier. For men, the risk of colorectal cancer in the youngest cohort is more than double that of the reference (incidence rate ratio, 2.57; 95% CI, 1.32-5.02). Incidence rate ratios were not significant for women (IRR, 2.12; 95% CI, 0.95-4.70) but increased in successively younger cohorts.
This study found increasing incidence of colorectal cancer diagnoses among Canadian men and women younger than 50 years of age. This increase in incidence among a low-risk population calls for additional research on possible risk factors that may be affecting these younger cohorts. It appears that primary prevention should be the highest priority to reduce the number of younger adults developing CRC in the future.
最近的证据表明，尽管老年人的结直肠癌（CRC）发病率正在下降，但 50 岁以下成年人的发病率却有所上升。鉴于年轻人通常被归类为疾病的低风险人群，这种流行病学转变令人担忧。
分析加拿大国家癌症发病率登记处的数据，以确定截至 2015 年的老年和年轻成年人 CRC 的发病率趋势。
设计、地点和参与者：本队列研究使用国家癌症发病率报告系统（1969-1992 年）和加拿大癌症登记处（1992-2015 年）的数据确定 CRC 的发病率。本研究纳入了 1969 年 1 月 1 日至 2015 年 12 月 31 日期间被诊断患有 CRC 的所有加拿大居民。分别对男性和女性以及>50 岁和<50 岁的年龄组进行了趋势检查。从 1886 年开始，使用每 5 年一组的出生队列模型，以 1936 年为参考队列。数据于 2018 年 5 月 13 日至 5 月 16 日进行分析。
CRC 的年化百分比变化和发病率比值。
1971 年至 2015 年，共发现 688515 例 CRC 新发病例（52.9%为女性）。尽管老年男性和女性的 CRC 发病率有所下降，但自 2006 年和 2010 年以来，年轻男性和女性的发病率有所上升。对于 50 岁以下的女性，自 2010 年以来，发病率每年平均增长 4.45%；对于 50 岁以下的男性，自 2006 年至 2015 年，发病率每年平均增长 3.47%。CRC 发病率与出生队列有关，较晚出生的队列风险更高。对于男性，最年轻队列患结直肠癌的风险是参考队列的两倍多（发病率比，2.57；95%CI，1.32-5.02）。女性的发病率比值无统计学意义（IRR，2.12；95%CI，0.95-4.70），但在年龄较小的队列中呈上升趋势。
本研究发现加拿大 50 岁以下男性和女性 CRC 诊断的发病率呈上升趋势。在低风险人群中发病率的增加要求对可能影响这些年轻人群的潜在危险因素进行更多研究。看来，初级预防应该是降低未来年轻成年人患 CRC 数量的首要任务。
