ELEVATED INTRASCROTAL TEMPERATURE AND THE INCIDENCE OF TESTICULAR CANCER IN NONCRYPTORCHID MEN

Abstract

The possibility that intrascrotal temperature is involved in the etiology of testicular cancer was investigated through a population-based case-control study conducted in western Washington State. A total of 323 men with germ cell tumors of the testis diagnosed between 1977 and 1984 and 658 randomly selected controls were interviewed with regard to type of shorts worn, use of long underwear, heat-resistant clothing, and hot tubs or saunas, and a history of varicocele. No association was found between testicular cancer and having worn tight-fitting underwear (jockey shorts) or having worn heat-resistant clothing on the job. A 50% increase in risk was observed for men who typically wore long underwear for more than three months out of the year, but this association was within the limits of chance given no true association. A smaller fraction of the men with cancer than controls had used a hot tub or sauna in the preceding five years, but the size of the case-control difference was not related to the frequency of use. The relative risk associated with a history of physician-diagnosed varicocele was 1.8 (95% confidence interval 0.9-3.4). There was little difference between men with seminomas and those with other germ cell tumors regarding any of the above exposures. Taken in aggregate, these results provide little or no support for the hypothesis that intermittent intrascrotal temperature elevation, to the degree encountered by US men today, plays a role in the etiology of germ cell testicular cancer. The possibility that risk increases after a continuous temperature increase, such as might result from a varicocele, needs to be evaluated further.