Division of Molecular Genetic Epidemiology, German Cancer Research Center, Heidelberg, Germany.
Clin Gastroenterol Hepatol. 2013 Aug;11(8):944-9. doi: 10.1016/j.cgh.2013.02.025. Epub 2013 Mar 15.
BACKGROUND & AIMS: Small intestinal cancer (SIC) is rare, and its etiology is poorly understood. We compared clusters of families with SICs of different histologic subtypes.
By using the nationwide family cancer data sets of Sweden and Finland, we identified a cohort of 9964 first-degree relatives of 1799 patients with SIC, diagnosed from 1961 through 2009. Data were collected from time periods as long as 47 years (mean, 35.4 y), and cancer incidence was determined. Standardized incidence ratios (SIRs) were calculated and stratified by sex, age, time period, and cancer type, using the incidence rates for the entire national population as the reference.
Among the 1799 SIC cases, 1.1% had a sibling with SIC, so the SIR was 11.8 (95% confidence interval [CI], 7.2-18.2); 1.1% had a parent or child with SIC (SIR, 3.5; 95% CI, 2.0-5.6). The SIR of concordant carcinoid histology of SIC among siblings was 28.4 (95% CI, 14.7-49.6; n = 12) and in parent-child pairs was 9.9 (95% CI, 5.4-16.6; n = 14). The familial risk of concordant histologic subtypes increased for siblings diagnosed with adenocarcinoma, but only 2 familial cases were identified. In family members of patients with SIC of the adenocarcinoma subtype, risks of colorectal and bladder cancer were modestly but significantly increased compared with the general population. Family members of patients with SIC of the carcinoid subtype had an increased risk for kidney cancer and polycythemia vera.
Based on data from our population-based study, first-degree relatives of patients with small intestinal carcinoid tumors have developed these tumors with high incidence. Because of the rareness of this tumor, the absolute risk remains moderate even within families. Gastroenterologists could inform patients with small intestinal carcinoids about the familial risk and encourage counseling for their first-degree relatives. Studies are needed to identify genetic factors that affect susceptibility to SIC.
小肠癌（SIC）较为罕见，其病因尚不清楚。本研究比较了不同组织学亚型 SIC 患者的家族聚集情况。
我们利用瑞典和芬兰全国范围内的家族癌症数据集，确定了 1961 年至 2009 年间诊断的 1799 例 SIC 患者的 9964 名一级亲属队列。收集了长达 47 年（平均 35.4 年）的数据，以确定癌症的发病率。使用整个国家人群的发病率作为参考，计算标准化发病比（SIR），并按性别、年龄、时间和癌症类型进行分层。
在 1799 例 SIC 患者中，有 1.1%的患者有兄弟姐妹患有 SIC，因此 SIR 为 11.8（95%置信区间[CI]，7.2-18.2）；1.1%的患者有父母或子女患有 SIC（SIR，3.5；95%CI，2.0-5.6）。SIC 中兄弟姐妹间一致性类癌组织学的 SIR 为 28.4（95%CI，14.7-49.6；n=12），在父母-子女对中为 9.9（95%CI，5.4-16.6；n=14）。诊断为腺癌的患者的兄弟姐妹中一致性组织学亚型的家族患病风险增加，但仅发现了 2 个家族病例。SIC 腺癌亚型患者的一级亲属中结直肠癌和膀胱癌的风险适度但显著增加，与普通人群相比。SIC 类癌亚型患者的一级亲属患肾癌和真性红细胞增多症的风险增加。
基于我们的基于人群的研究数据，小肠类癌肿瘤患者的一级亲属已患有此类肿瘤，发病率较高。由于这种肿瘤较为罕见，即使在家族中，绝对风险仍然适中。胃肠病学家可以向患有小肠类癌的患者告知家族患病风险，并鼓励对其一级亲属进行咨询。需要进行研究以确定影响 SIC 易感性的遗传因素。
