Proliferative activity of urothelium and tumors of renal pelvis, ureter, and urinary bladder evaluated by thymidine labeling

Carcinoma of the urinary bladder is among the more frequent neoplasms in the United States, with an estimated 37,100 new cases diagnosed in 1982, 27,000 in males and 10,100 in females.' In addition, more than 2,000 new cases of carcinoma of the renal pelvis and ureter would be expected during the same one-year period. 1.2 The urethra is less often the site of the presenting carcinoma," but carcinoma in situ of the urethra may coexist with invasive bladder carcinoma," and subsequently become invasive after treatment of the bladder carcinoma. 5 Both stage" and histologic grade? influence the course of the disease and response to therapy. The proliferative rate of urothelial carcinoma could be another determinant of prognosis. Prior studies have shown that normal epithelium and carcinomas of the urinary bladder can be labeled in vitro with tritiated thymidine and S-phase cells thereby detected.v" Veenema, Fingerhut, and Craff!" and Hainau and Dornbernowsky? reported that carcinomas of high histologic grade had a;high thymidine labeling index (TLI) compared with low-grade carcinomas. Histologically low-grade carcinomas with high TLI tended to have rapid clinical courses. 10 Flat transitional cell carcinomas were