Differences in the aetiology of testicular cancer by histological tumour type

There are two main histological groups of testicular germ cell rumours, which may have different risk factors. Some authors have examined these risk factors by histological group but few consistent differences have been detected. The aim of this study was to examine histological differences using the UK National Case-central study of Testicular Cancer. Seven hundred and ninety four pairs of cases and controls were included in this study. Four hundred of the cases had pure seminoma tumours, with 394 cases of non-seminoma histology. The risk of seminoma associated with undescended testis was higher than that for non-seminoma tumours (odds ratio of 5.30 compared with 3.00). This difference was most marked in men aged 31 and over (odds ratio of 11.94 compared with 5.10). The risks associated with vasectomy and testis or groin injuries were higher in the non-seminoma group. Some differences were also detected for participation in sports and employment in specific jobs. Whilst some of the differences detected may have arisen by chance, the stronger association between undescended testis and pure seminoma has been identified by a number of other studies and is likely to reflect a genuine difference in aetiology.