McNally Richard J Q, Alexander Freda E, Vincent Tim J, Murphy Michael F G
School of Clinical Medical Sciences (Child Health), Sir James Spence Institute, Newcastle University, Royal Victoria Infirmary, Newcastle-upon-Tyne, UK.
Int J Cancer. 2009 Feb 15;124(4):932-6. doi: 10.1002/ijc.23965.
The aetiology of childhood cancer is poorly understood. Both genetic and environmental factors are likely to be involved. The presence of spatial clustering is indicative of a very localized environmental component to aetiology. Spatial clustering is present when there are a small number of areas with greatly increased incidence or a large number of areas with moderately increased incidence. To determine whether localized environmental factors may play a part in childhood cancer aetiology, we analyzed for spatial clustering using a large set of national population-based data from Great Britain diagnosed 1969-1993. The Potthoff-Whittinghill method was used to test for extra-Poisson variation (EPV). Thirty-two thousand three hundred and twenty-three cases were allocated to 10,444 wards using diagnosis addresses. Analyses showed statistically significant evidence of clustering for acute lymphoblastic leukaemia (ALL) over the whole age range (estimate of EPV = 0.05, p = 0.002) and for ages 1-4 years (estimate of EPV = 0.03, p = 0.015). Soft-tissue sarcoma (estimate of EPV = 0.03, p = 0.04) and Wilms tumours (estimate of EPV = 0.04, p = 0.007) also showed significant clustering. Clustering tended to persist across different time periods for cases of ALL (estimate of between-time period EPV = 0.04, p =0.003). In conclusion, we observed low level spatial clustering that is attributable to a limited number of cases. This suggests that environmental factors, which in some locations display localized clustering, may be important aetiological agents in these diseases. For ALL and soft tissue sarcoma, but not Wilms tumour, common infectious agents may be likely candidates.
儿童癌症的病因目前还知之甚少。遗传因素和环境因素可能都有涉及。空间聚集现象的存在表明病因中存在非常局部化的环境因素。当少数地区发病率大幅上升或大量地区发病率中度上升时，就会出现空间聚集现象。为了确定局部环境因素是否可能在儿童癌症病因中起作用，我们使用了1969年至1993年期间英国基于全国人口的大量数据，对空间聚集进行了分析。采用波特霍夫-惠廷希尔方法来检验泊松外变异（EPV）。利用诊断地址将32323例病例分配到10444个病房。分析显示，在整个年龄范围内，急性淋巴细胞白血病（ALL）存在统计学上显著的聚集证据（EPV估计值=0.05，p=0.002），在1至4岁年龄组中也有（EPV估计值=0.03，p=0.015）。软组织肉瘤（EPV估计值=0.03，p=0.04）和肾母细胞瘤（EPV估计值=0.04，p=0.007）也显示出显著的聚集。ALL病例在不同时间段的聚集趋势持续存在（时间段间EPV估计值=0.04，p=0.003）。总之，我们观察到由于病例数量有限导致的低水平空间聚集。这表明，在某些地方显示出局部聚集的环境因素可能是这些疾病的重要致病因素。对于ALL和软组织肉瘤，而非肾母细胞瘤，常见的传染原可能是潜在的致病因素。
