Risk of testicular cancer with cryptorchidism and with testicular biopsy: cohort study.

Swerdlow et al studied a cohort of 1075 men who had been treated for cryptorchidism. In 120 testes that had been biopsied at the time of orchiopexy the relative risk of subsequent development of testicular cancer was 66.7. The corresponding relative risk in 1285 undescended testes that had also been operated on but not biopsied was 6.7. The estimate for testes that were not biopsied is about as expected, but the high relative risk of testicular cancer in biopsied testes is a new finding not yet substantiated by other studies. A potential weakness of the study is the unclear criteria for biopsy in 9% of the testes in the series; this leaves open the possibility of selection bias if testes with a high risk of subsequent malignancy were preferably biopsied. To explore the risk of testicular cancer in an unselected population of biopsied undescended testes, we investigated a cohort of 830 men who had surgical treatment of 1026 undescended testes at this hospital between January 1971 and January 1992.