Cryptorchism, orchiopexy, and the risk of testicular cancer.

Adult white male residents of 13 counties of western Washington State in whom germ cell testicular cancer was diagnosed between 1977 and 1983 (n = 333) were interviewed by telephone regarding their history of cryptorchism and its treatment. The same interview was given to a sample of 675 men selected from the population of these counties by dialing telephone numbers at random. Men who reported a history of cryptorchism were 5.9 times (95 per cent confidence interval 3.4-10.2) more likely than men without such a history to develop testicular cancer. Compared with noncryptorchid men, those with unilateral cryptorchism were at greater risk of developing a tumor on the side of nondescent (relative risk = 8.0) than on the opposite side (relative risk = 1.6). The size of the increased risk tended to be smaller among cryptorchid men who had undergone orchiopexy by age 10 than for other cryptorchid men, but the influence of orchiopexy in early childhood could not be evaluated in this population. These observations offer support for the hypothesis that one or more local factors (e.g., temperature elevation) account for the major part of the increased risk of germ cell testicular tumors in cryptorchid men.