[Double cancer in urology]

Since our clinic opened eight years ago, we have experienced a total of 397 patients with 400 tumors in the urinary system. Of them, 29 double tumors were observed in 26 patients. Statistical investigation was made on these double tumors. In this study, the definition of Billroth was employed and, in addition, a patient presenting with previous history of cancer and showing traces of any treatment was diagnosed as having double cancer. As a result, the incidence of double cancer was as high as 6.6%, although the disease has been considered to be rare. It is evident that double cancer is not rare. The disease was not specific to any organ concerning the urinary system and its incidence was higher in the female patients. Of 11 female patients with double cancer, 7 suffered from uterine cancer. The primary cancer had appeared in the uterine in 6 patients and all the 6 developed secondary cancer in the pelvic viscera (the urinary bladder and the lower part of the ureter). The mean age at which the patients developed the secondary cancer in the pelvic viscera was almost significantly lower in those in whom uterine cancer was the primary one than those in whom the primary cancer had not occurred in the uterine. This suggests that the operative procedures inside the pelvis or irradiation for the treatment of uterine cancer is related to the onset of the secondary cancer in the pelvic viscera.