Yang Daniel X, Gross Cary P, Soulos Pamela R, Yu James B
Yale University School of Medicine, New Haven, Connecticut; Cancer Outcomes, Public Policy, and Effectiveness Research (COPPER) Center, New Haven, Connecticut.
Cancer. 2014 Sep 15;120(18):2893-901. doi: 10.1002/cncr.28794. Epub 2014 Jun 3.
Ideally, screening detects cancer at a more curable stage and, as a result, decreases the rate of subsequent diagnosis at a late stage. Although it is suggested that some cancer screening tests have led to substantial increases in early-stage incidence with only marginal reductions in late-stage incidence (eg mammography), the association between temporal trends in colorectal cancer screening and its cumulative impact on colorectal cancer incidence is unknown.
Colorectal cancer incidence data spanning over 3 decades (1976-2009) were collected from the Surveillance, Epidemiology, and End Results database. Data on screening use spanning the period from 1986 to 2010 were collected from the National Cancer Institute Cancer Trends Progress Report, and trends in the incidence of early-stage (in situ, local) and late-stage (regional, distant) colorectal cancer were examined among adults aged ≥50 years.
From 1987 to 2010--the years for which screening data were available--the percentage of adults aged ≥50 years who underwent screening rose from 34.8% to 66.1% (which included increases in colonoscopy). During that time, the incidence of late-stage colorectal cancer decreased from 118 to 74 cases per 100,000 population (P < .001). The incidence of early-stage colorectal cancer also decreased, from 77 to 67 cases per 100,000 population (P < .001). After adjusting for underlying trends in cancer incidence, colorectal screening was associated with a reduction of approximately 550,000 cases of colorectal cancer over the past 3 decades in the United States.
There has been a significant decline in the incidence of colorectal cancer in the United States, particularly for late-stage disease, during a time of increasing rates of screening.
理想情况下，筛查能在癌症更可治愈的阶段检测出癌症，从而降低后续晚期诊断率。尽管有人认为一些癌症筛查测试已使早期发病率大幅上升，而晚期发病率仅略有下降（如乳腺钼靶检查），但结直肠癌筛查的时间趋势与其对结直肠癌发病率的累积影响之间的关联尚不清楚。
从监测、流行病学和最终结果数据库收集了跨越30多年（1976 - 2009年）的结直肠癌发病率数据。从美国国家癌症研究所癌症趋势进展报告中收集了1986年至2010年期间的筛查使用数据，并对年龄≥50岁的成年人中早期（原位、局部）和晚期（区域、远处）结直肠癌的发病率趋势进行了研究。
在有筛查数据的1987年至2010年期间，年龄≥50岁接受筛查的成年人比例从34.8%升至66.1%（其中包括结肠镜检查的增加）。在此期间，晚期结直肠癌的发病率从每10万人118例降至74例（P <.001）。早期结直肠癌的发病率也有所下降，从每10万人77例降至67例（P <.001）。在调整癌症发病率的潜在趋势后，在美国过去30年中，结直肠癌筛查与约55万例结直肠癌病例的减少相关。
在美国，在筛查率上升的时期，结直肠癌的发病率显著下降，尤其是晚期疾病。
