The Influence of Phenacetin or Mechanical Perforation on the Development of Renal Pelvic and Urinary Bladder Tumors in Fanft‐induced Urinary Tract Carcinogenesis

The influence of 0.535% phenacetin in the diet or mechanical perforation of the renal pelvis and urinary bladder of male Sprague-Dawley rats in FANFT-induced urinary tract carcinogenesis was studied. The 151 rats were divided into 5 experimental and one control group. The rats were followed for up to 80 weeks. FANFT administered at 0.2% in the diet for 11 weeks resulted in a high incidence of urinary tract tumors particularly of the renal pelvis. Similar results were obtained by administration of 0.2% FANFT for 6 weeks followed by 0.535% phenacetin while FANFT for 6 weeks preceded or followed by mechanical perforation of the renal pelvis resulted in a significantly lower incidence of renal pelvic tumors. Phenacetin appeared to enhance the development of renal pelvic tumors in FANFT-induced urinary tract carcinogenesis. In contrast no effect of phenacetin on the urinary bladder could be detected.