Am J Epidemiol. 2013 Oct 15;178(8):1240-5. doi: 10.1093/aje/kwt100. Epub 2013 Aug 8.
Testicular germ cell tumors (TGCTs), the most common neoplasms of young men, are categorized histologically as either seminomas or nonseminomas/mixed germ cell tumors. These subtypes differ by age at diagnosis and clinical course, but little is known about etiological distinctions. To test the hypothesis that histological subtypes have distinct sets of unrecognized etiological factors, we used a recently described approach, estimating the association between histological types of first and second tumors of men with 2 primary TGCTs. The study population of 488 men each with 2 primary TGCTs was ascertained through population-based cancer registries in the United States between 1972 and 2006. Univariate logistic regression analysis revealed that the histology of second primary TGCTs was associated with the histology of first TGCTs (odds ratio = 1.70, 95% confidence interval: 1.14, 2.52); however, the association did not persist in analyses adjusted for age at diagnosis of first TGCT (odds ratio = 1.09, 95% confidence interval: 0.71, 1.70). These results would be expected if the subtypes share etiology but experience different rates of progression to diagnosis or if the histological fate of TGCTs is influenced by age-related processes. Men with 2 primary TGCTs provide novel opportunities to learn whether histological subtypes are likely to share etiology, so results may inform research designed to identify causes.
睾丸生殖细胞肿瘤（TGCTs）是最常见的青年男性肿瘤，组织学上可分为精原细胞瘤或非精原细胞瘤/混合性生殖细胞肿瘤。这些亚型在诊断时的年龄和临床过程上有所不同，但对其病因学差异知之甚少。为了验证组织学亚型是否具有不同的未被识别的病因因素这一假说，我们采用了一种新描述的方法，估计了具有 2 个原发性 TGCT 的男性的第一个和第二个肿瘤的组织学类型之间的关联。该研究的 488 名男性，每个男性都有 2 个原发性 TGCT，他们是通过美国在 1972 年至 2006 年期间基于人群的癌症登记处确定的。单变量逻辑回归分析显示，第二个原发性 TGCT 的组织学与第一个 TGCT 的组织学相关（优势比=1.70，95%置信区间：1.14，2.52）；然而，在调整了第一个 TGCT 的诊断年龄后，这种关联并不存在（优势比=1.09，95%置信区间：0.71，1.70）。如果亚型具有共同的病因，但经历了不同的进展到诊断的速度，或者 TGCT 的组织学命运受到与年龄相关的过程的影响，那么就会出现这种结果。具有 2 个原发性 TGCT 的男性为了解组织学亚型是否可能具有共同的病因提供了新的机会，因此研究结果可能会为旨在确定病因的研究提供信息。
