Multiple primary tumours of the urogenital system: our cases and a review of the literature.

We had 6 genitourinary tumour patients with other primary tumours in a 147 genitourinary tumour patient group. Two of these tumours developed synchronously while the others were metachronous, and two of them developed in the genitourinary system. It is clear that cancer patients have a higher risk of a second cancer than the general population. Second cancers may be detected in long-term follow-up of cancer patients, or may be caused by the aetiologic factor(s) with pleiotropic effects, or may develop because of the therapies for the first cancer.