Cryptorchidism, hernia, and cancer of the testis.

Risk of cancer of the testis was related to nondescent and hernia in a comparison of 596 testicular cancer patients and 602 unaffected men who had been in active service in the U.S. Army between 1950 and 1970. Medical histories were obtained from routine service records. Undescended testis was associated with a testicular cancer risk 8.8 times that of normal. Among cancer patients with a history of undescended testis, seminomas were nearly twice as frequent as in the remaining patients. Of 14 patients with unilateral undescended testis, 12 had the tumor on the side of the defect. Testicular cancer risk was estimated to be 2.9 times higher in men who had reported having had an inguinal hernia than in those who had not. Side of hernia and side of tumor were not associated; histologic type was not related to history of hernia.