Konstantinoudis Garyfallos, Kreis Christian, Ammann Roland A, Niggli Felix, Kuehni Claudia E, Spycher Ben D
Faculty of Medicine, Institute of Social and Preventive Medicine (ISPM), University of Bern, Finkenhubelweg 11, 3012, Bern, Switzerland.
Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Cancer Causes Control. 2018 Mar;29(3):353-362. doi: 10.1007/s10552-018-1011-6. Epub 2018 Feb 13.
Childhood cancers are rare and little is known about their etiology. Potential risk factors include environmental exposures that might implicate spatial variation of cancer risk. Previous studies of spatial clustering have mainly focused on childhood leukemia. We investigated spatial clustering of different childhood cancers in Switzerland using exact geocodes of place of residence.
We included 6,034 cancer cases diagnosed at age 0-15 years during 1985-2015 from the Swiss Childhood Cancer Registry. Age and sex-matched controls (10 per case) were randomly sampled from the national censuses (1990, 2000, 2010). Geocodes of place of residence were available at birth and diagnosis for both cases and controls. We used the difference in k-functions and Cuzick-Edwards test to assess global clustering and Kulldorff's circular scan to detect individual clusters. We also carefully adjusted for multiple testing.
After adjusting for multiple testing, we found no evidence of spatial clustering of childhood cancers neither at birth (p = 0.43) nor diagnosis (p = 0.13). Disregarding multiple testing, results of individual tests indicated spatial clustering of all childhood cancers combined (p < 0.01), childhood lymphoma (p = 0.01), due to Hodgkin lymphoma (HL) (p = 0.02) at diagnosis, and embryonal tumors of the central nervous system (CNS) at birth and diagnosis, respectively (p = 0.05 and p = 0.02).
This study provides weak evidence of spatial clustering of childhood cancers. Evidence was strongest for HL and embryonal CNS tumors, adding to the current literature that these cancers cluster in space.
儿童癌症较为罕见，其病因鲜为人知。潜在风险因素包括可能与癌症风险空间变异有关的环境暴露。以往关于空间聚集性的研究主要集中在儿童白血病。我们利用居住地的精确地理编码，对瑞士不同儿童癌症的空间聚集性进行了调查。
我们纳入了瑞士儿童癌症登记处1985 - 2015年期间诊断的6034例0至15岁的癌症病例。年龄和性别匹配的对照（每例病例10名）从全国人口普查（1990年、2000年、2010年）中随机抽取。病例和对照在出生时及诊断时均有居住地的地理编码。我们使用k函数差异和Cuzick - Edwards检验来评估全局聚集性，并使用Kulldorff圆形扫描来检测个体聚集区。我们还仔细校正了多重检验。
校正多重检验后，我们未发现儿童癌症在出生时（p = 0.43）或诊断时（p = 0.13）存在空间聚集性证据。不考虑多重检验时，个别检验结果表明，所有儿童癌症综合起来（p < 0.01）、儿童淋巴瘤（p = 0.01）、诊断时因霍奇金淋巴瘤（HL）（p = 0.02）以及出生时和诊断时的中枢神经系统胚胎性肿瘤（分别为p = 0.05和p = 0.02）存在空间聚集性。
本研究提供了儿童癌症空间聚集性较弱证据。HL和中枢神经系统胚胎性肿瘤的证据最为有力，这为这些癌症在空间上聚集的现有文献增添了内容。
