Bray Freddie, Richiardi Lorenzo, Ekbom Anders, Forman David, Pukkala Eero, Cuninkova Martina, Møller Henrik
Cancer Registry of Norway, Montebello, Oslo.
Cancer Epidemiol Biomarkers Prev. 2006 Apr;15(4):652-8. doi: 10.1158/1055-9965.EPI-05-0565.
The incidence of the two main clinical subentities of testicular germ cell cancer (seminoma and nonseminoma) is increasing throughout Europe. Most studies have revealed little variation in risk factors between the two subtypes. This study compared generation-specific trends in eight European countries, hypothesizing that similar temporal pattern by birth cohort implied that seminoma and nonseminoma had a largely comparable etiology. The results are presented using the age-period-cohort model and the nonidentifiability problem highlighted by partitioning the age, period, and cohort effects in terms of their linear and curvature component parts, assuming a priori that cohort effects predominated. Despite uniform overall increases by calendar period, declining rates of nonseminoma but not pure seminoma were observed in the majority of countries during the 1990s. The subtype trends were, however, largely analogous on a birth cohort scale. Notable observations were a decline in rates of both subtypes among recent birth cohorts in Switzerland and a short-term wartime effect in several countries, involving an attenuation of increasing risk of both subtypes in men born in 1940 to 1945. Departures from the steady increases in testicular cancer over time were likely to occur for nonseminomas some years ahead of seminoma on a period scale. The importance of birth cohort coincided with the view that given a short time interval of susceptibility to exposures earlier in life and a biologically constant time to diagnosis, all temporal changes in rate-limiting exposures should appear as generational effects. Trends in seminoma and nonseminoma conform to largely the same temporal patterns on this scale, implying that they share important etiologic factors.
睾丸生殖细胞癌的两个主要临床亚实体（精原细胞瘤和非精原细胞瘤）在整个欧洲的发病率都在上升。大多数研究表明，这两种亚型之间的风险因素差异不大。本研究比较了八个欧洲国家特定代际的趋势，假设按出生队列划分的相似时间模式意味着精原细胞瘤和非精原细胞瘤在很大程度上具有可比的病因。使用年龄-时期-队列模型呈现结果，并通过将年龄、时期和队列效应按其线性和曲率组成部分进行划分来突出不可识别性问题，前提是先验假设队列效应占主导。尽管按日历时期总体呈一致上升趋势，但在20世纪90年代，大多数国家非精原细胞瘤的发病率下降，而纯精原细胞瘤的发病率未下降。然而，在出生队列层面，亚型趋势在很大程度上是相似的。值得注意的观察结果是，瑞士近期出生队列中两种亚型的发病率均下降，以及几个国家出现短期战时效应，即1940年至1945年出生男性中两种亚型风险增加的趋势有所减弱。在时期尺度上，非精原细胞瘤发病率偏离随时间稳步上升的情况可能比精原细胞瘤提前数年出现。出生队列的重要性与以下观点一致，即鉴于生命早期暴露的易感性时间间隔较短且诊断的生物学时间恒定，限速暴露的所有时间变化都应表现为代际效应。在这个尺度上，精原细胞瘤和非精原细胞瘤的趋势在很大程度上符合相同的时间模式，这意味着它们共享重要的病因因素。
