OBJECTIVES Despite overall reductions in colorectal cancer burden, incidence rates continue to rise among younger patients, and causes remain unknown. We examined differences in clinicopathologic and racial/ethnic characteristics within the adolescent and young adult (AYA) population diagnosed with colorectal cancer in the United States. METHODS Using the National Cancer Institute's Surveillance, Epidemiology, and End Results program data, we identified individuals diagnosed with first primary colorectal cancer between ages 15 and 39 years from 2010 to 2015. Adjusted multivariable logistic regression models were used to quantify clinicopathologic and racial/ethnic differences across age at onset subgroups (15-19, 20-24, 25-29, 30-34, and 35-39 years). RESULTS We identified 5,350 AYA patients diagnosed with colorectal cancer. Of note, 28.6% of AYA cases were diagnosed with right-sided tumors (cecum to transverse colon). The proportion of right-sided colorectal cancers differed significantly by age group at diagnosis (38.3% vs 27.3% of AYAs aged 15-19 vs 35-39 years, respectively; P trend = 0.01). Proportions of cases with mucinous adenocarcinoma and signet ring cell carcinoma histopathologic subtypes significantly increased with younger age at onset (P trends = 0.01 and 0.03, respectively). Differences in clinical stage were observed across AYA age groups, with stage II disease increasing with younger age (P trend = 0.01). The proportion of Hispanic AYAs was higher within younger patients, accounting for 21.0% of the AYA population aged 35-39 years up to 28.3% of 15-19-year-old individuals (P trend = 0.003). DISCUSSION Within the AYA population, colorectal cancers differ by clinicopathologic and racial/ethnic characteristics. Further investigation of the clinical and biologic diversity of colorectal cancers that partially underlie age- and race-related differences in cancer susceptibility and outcomes is warranted.

中文翻译：

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青少年和年轻人之间结直肠癌的临床病理和种族/种族差异。

目的尽管结直肠癌的负担总体上有所减轻，但年轻患者的发病率继续上升，其原因仍然未知。我们检查了在美国诊断为大肠癌的青少年（AYA）人群中临床病理和种族/种族特征的差异。方法使用美国国家癌症研究所的监测，流行病学和最终结果计划数据，我们确定了2010年至2015年年龄在15至39岁之间的首例原发性结肠直肠癌患者。调整后的多因素Logistic回归模型用于量化临床病理和种族/种族发病亚组（15-19岁，20-24岁，25-29岁，30-34岁和35-39岁）的年龄差异。结果我们确定了5,350名被诊断患有大肠癌的AYA患者。值得注意的是28。6％的AYA患者被诊断出患有右侧肿瘤（盲肠至横结肠）。诊断时右侧大肠癌的比例存在显着差异（15-19岁的AYAs分别为35-39岁的AYAs的38.3％vs 27.3％； P趋势= 0.01）。粘液腺癌和印戒细胞癌组织病理学亚型病例的比例随着发病年龄的增加而显着增加（P趋势分别为0.01和0.03）。在AYA年龄组中观察到临床阶段的差异，随着年龄的增长，II期疾病呈上升趋势（P趋势= 0.01）。在较年轻的患者中，西班牙裔AYA的比例较高，占35-39岁的AYA人群的21.0％，占15-19岁的28.3％（P趋势= 0.003）。讨论在AYA人群中，大肠癌的临床病理和种族/种族特征不同。有必要进一步研究结直肠癌的临床和生物学多样性，这些差异部分是与年龄和种族相关的癌症易感性和结果差异的部分原因。