[Tumors of the efferent parts of the urinary tract and abuse of analgesics].

Since 1965, when Swedish authors first suggested that analgesic abuse could cause uroepithelial tumors associated with or without analgesic nephropathy, an increasing number of cases have been reported from many parts of the world. In a retrospective analysis of all patients admitted to the medical department of the University Hospital in Basel from 1966 to 1976, records of 20 patients with analgesic nephropathy and tumors of the urinary tract (excluding hypernephroma) were found (17 uroepithelial tumors, 2 sarcomas, 1 chorionepithelioma). Typical symptoms, outcome and actuarial survival of the patients with uroepithelial tumors are summarized. Phenacetin as the common ingredient in analgesic mixtures has been regarded as carcinogenic, since some of its metabolites are similar in chemical structure to well-known industrial carcinogens. In animal experiments malignant tumors have in fact been induced with 2-hydroxylated metabolites and areneoxydes of phenacetin and paracetamol, and there is even more convincing evidence of the carcinogenic properties of N-oxydized metabolites such as N-hydroxy-phenetidine and N-hydroxy-phenacetin. Dimethylnitrosamine formed from aminophenazone appears to be improbable as a cause of uroepithelial tumors associated with analgesic abuse, since aminophenazone has not been a common ingredient of analgesic mixtures in Australia, where the incidence of uroepithelial tumors appears to be as high as in Sweden, where abuse of aminophenazone-containing analgesics has been massive.