Mellemkjaer Lene, Hasle Henrik, Gridley Gloria, Johansen Christoffer, Kjaer Susanne K, Frederiksen Kirsten, Olsen Jørgen H
Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark.
Paediatr Perinat Epidemiol. 2006 May;20(3):231-7. doi: 10.1111/j.1365-3016.2006.00717.x.
Cancer risk in children born before term has been assessed in a large number of case-control studies but very rarely in cohort studies. We carried out a cohort study of 35 178 children with the diagnosis immaturity at birth in the Hospital Discharge Register during 1977-89. The children were followed for cancer in the Danish Cancer Registry until 1994 and comparisons were made with incidence rates for all children in Denmark. The 64 observed cases of childhood cancer in the cohort corresponded closely to the expected number {standardised incidence ratio (SIR) = 1.03; [95% confidence interval (CI) 0.80, 1.32]}. The only cancer site with an observed number that deviated significantly from the expected number was central nervous system (CNS) tumours (26 cases observed; SIR = 1.57; [95% CI 1.02, 2.30]) in particular medulloblastoma (9 cases observed; SIR = 3.1; [95% CI 1.4, 5.9]). In a nested case-control study of the CNS tumours, we found that more cases than controls had been exposed to diagnostic X-rays, but the result was not significant. Surprisingly, for those born before term, the risk of CNS tumours increased with increasing gestational age in the nested case-control data. Our results are in line with previous evidence that children born before term are not at increased risk for childhood cancer in general. An explanation behind the excess of CNS tumours could not be identified, but the effect of diagnostic X-rays in newborns may deserve further attention.
大量病例对照研究评估了早产儿童的癌症风险，但队列研究却极为罕见。我们对1977 - 1989年期间医院出院登记册中出生时诊断为不成熟的35178名儿童进行了队列研究。这些儿童在丹麦癌症登记处进行癌症随访，直至1994年，并与丹麦所有儿童的发病率进行比较。队列中观察到的64例儿童癌症病例与预期数量密切相符{标准化发病率（SIR）= 1.03；[95%置信区间（CI）0.80，1.32]}。唯一观察数量与预期数量有显著偏差的癌症部位是中枢神经系统（CNS）肿瘤（观察到26例；SIR = 1.57；[95% CI 1.02，2.30]），特别是髓母细胞瘤（观察到9例；SIR = 3.1；[95% CI 1.4，5.9]）。在一项针对CNS肿瘤的巢式病例对照研究中，我们发现病例组比对照组接受诊断性X线照射的更多，但结果并不显著。令人惊讶的是，在巢式病例对照数据中，对于早产儿童，CNS肿瘤的风险随着胎龄增加而升高。我们的结果与之前的证据一致，即一般来说早产儿童患儿童癌症的风险并未增加。虽然无法确定CNS肿瘤过多的原因，但新生儿诊断性X线照射的影响可能值得进一步关注。
