Background: Colorectal cancer remains the second leading cause of cancer-related death in the US. As early-onset colorectal cancer (EO-CRC) becomes more prevalent in the US, research attention has shifted towards identifying at-risk populations. Previous studies have highlighted the rising rate of early-onset adenocarcinoma (ADC) and neuroendocrine tumors (NET) in the US. However, data on geographical variations of EO-CRC are scarce. Hence, our study aims to analyze time trends in EO-CRC incidence rates across various US regions and to assess these trends by sex and histopathological subtypes (ADC and NET). Methods: We analyze data spanning from 2001 to 2020 from the United States Cancer Statistics (USCS) database, covering nearly 98% of the US population. Using SEER*Stat software version (8.4.2, NCI), we calculated EO-CRC incidence rates among adults aged 20–54 years, adjusting for the age standard 2000 US population. The rates were categorized by sex and US geographical regions into west, midwest, northeast, and south. Time trends, reported as annual percentage change (APC) and average APC (AAPC), were generated via Joinpoint Regression software (v.5.0.2, NCI) utilizing the weighted Bayesian Information Criteria “BIC” method to generate the best-fit trends with a two-sidedp-value cutoff at 0.05. The rates were also stratified by histopathology into ADC and NET. Results: Between 2001 and 2020, a total of 514,875 individuals were diagnosed with early-onset CRC in the US, with 54.78% being men. Incidence rates and trends varied across geographical regions. In the western region (comprising 106,685 patients, 54.85% men), incidence rates significantly increased in both women (AAPC = 1.37,p< 0.001) and men (AAPC = 1.34,p< 0.001). Similarly, in the midwestern region (with 110,380 patients, 55.46% men), there were significant increases in incidence rates among women (AAPC = 1.06,p< 0.001) and men (AAPC = 1.35,p< 0.001). The northeastern region (with 94,758 patients, 54.53% men) also witnessed significant increases in incidence rates for both women (AAPC = 0.71,p< 0.001) and men (AAPC = 0.84,p< 0.001). In contrast, the southern region (with 203,052 patients, 54.48% men) experienced slower increases in incidence rates among both women and men (AAPC = 0.25,p< 0.05 in women; AAPC = 0.66,p< 0.05 in men). When stratified by histopathology, incidence rates for adenocarcinomas (ADC) increased in all regions, most notably in the west (AAPC = 1.45,p< 0.05), and least in the south (AAPC = 0.46,p< 0.05). Conversely, for neuroendocrine tumors (NET), while incidence rates increased similarly across all regions, the pace was notably faster compared to ADC, particularly in the west (AAPC = 3.26,p< 0.05) and slower in the south (AAPC = 2.24,p< 0.05) Discussion: Our analysis of nationwide US data spanning two decades and encompassing over half a million early-onset CRC patients, representing nearly 98% of the US population, highlights significant temporal variation in incidence rates across various geographical regions. The most substantial increases in incidence rates were observed in the west, while the least pronounced changes were noted in the south, affecting both men and women. These trends persisted across the main CRC histopathological subtypes, with NET exhibiting a notably swifter pace of increase compared with ADC. These findings hold important implications for public health strategies and underscore the need for targeted interventions to address the rising burden of early-onset CRC across different regions in the US.
背景：结直肠癌仍是美国癌症相关死亡的第二大原因。随着早发性结直肠癌在美国日益普遍，研究重点已转向识别高危人群。既往研究已指出美国早发性腺癌和神经内分泌肿瘤的发病率呈上升趋势。然而，关于早发性结直肠癌地域差异的数据尚显不足。因此，本研究旨在分析美国不同地区早发性结直肠癌发病率的时间趋势，并按性别和组织病理学亚型（腺癌与神经内分泌肿瘤）进行评估。 方法：我们分析了美国癌症统计数据库2001年至2020年的数据，覆盖近98%的美国人口。使用SEER*Stat软件（8.4.2版，美国国家癌症研究所），我们计算了20-54岁成年人的早发性结直肠癌发病率，并按2000年美国标准人口进行年龄调整。发病率按性别和美国地理区域（西部、中西部、东北部和南部）分类。通过Joinpoint回归软件（5.0.2版，美国国家癌症研究所）采用加权贝叶斯信息准则方法生成最佳拟合趋势，以年度百分比变化和平均年度百分比变化报告时间趋势，双侧p值临界值设为0.05。发病率还按组织病理学分为腺癌和神经内分泌肿瘤进行分层分析。 结果：2001年至2020年间，美国共有514,875人被诊断为早发性结直肠癌，其中54.78%为男性。不同地理区域的发病率和趋势存在差异。在西部地区（包含106,685例患者，54.85%为男性），女性和男性的发病率均显著上升（女性AAPC = 1.37, p < 0.001；男性AAPC = 1.34, p < 0.001）。同样，在中西部地区（包含110,380例患者，55.46%为男性），女性和男性的发病率也显著增加（女性AAPC = 1.06, p < 0.001；男性AAPC = 1.35, p < 0.001）。东北部地区（包含94,758例患者，54.53%为男性）女性和男性的发病率同样显著上升（女性AAPC = 0.71, p < 0.001；男性AAPC = 0.84, p < 0.001）。相比之下，南部地区（包含203,052例患者，54.48%为男性）女性和男性的发病率增长较缓（女性AAPC = 0.25, p < 0.05；男性AAPC = 0.66, p < 0.05）。按组织病理学分型分析，所有地区的腺癌发病率均有所上升，其中西部地区增幅最大（AAPC = 1.45, p < 0.05），南部地区增幅最小（AAPC = 0.46, p < 0.05）。相反，神经内分泌肿瘤的发病率在所有地区均呈上升趋势，且增速明显快于腺癌，其中西部地区最快（AAPC = 3.26, p < 0.05），南部地区最慢（AAPC = 2.24, p < 0.05）。 讨论：我们对涵盖美国近98%人口、跨越二十年、包含超过50万早发性结直肠癌患者的全国性数据进行分析，揭示了不同地理区域发病率存在显著的时间异质性。西部地区发病率增幅最为显著，而南部地区变化最小，这一趋势在男女性别中均保持一致。这些趋势在主要结直肠癌组织病理学亚型中持续存在，其中神经内分泌肿瘤的增速明显快于腺癌。这些发现对公共卫生策略具有重要意义，并强调需要采取针对性干预措施，以应对美国不同地区日益加重的早发性结直肠癌疾病负担。
Geographical Variations in Early Onset Colorectal Cancer in the United States between 2001 and 2020
肿瘤(癌症)患者之家