Testicular cancer risk in boys with maldescended testis: a cohort study.

Testicular maldescent is considered as a predisposing condition for development of testicular malignancy. Male subjects with a history of cryptorchidism have been suggested by some authors to have a 40 to 50 times increased risk of testis cancer. However, the magnitude of this risk is a point of considerable disagreement. Therefore, we studied the records of 506 consecutive patients hospitalized for maldescended testis from January 1949 to December 1960. Testis cancer developed in 6 patients, which when compared to the 1.3 expectant Danish incidence rate, yielded a statistically significant relative risk of 4.7 (95 per cent confidence interval 1.7 to 10.2). Thus, our study confirmed that male subjects with a history of testicular maldescent have an increased risk for testis cancer, although the magnitude of this risk was lower than suggested previously.