Analysis of bladder carcinoma by subsite. Cystoscopic location may have prognostic value. Nine hundred fourteen cases of carcinoma of the urinary bladder registered from 1977 to 1988 with the Kansas state tumor registry were evaluated by subsite for differences in grade, histology, sex, age at diagnosis, and survival. Only initial occurrences of carcinoma were included. Carcinoma of the lateral walls accounted for 37.1%; the posterior wall, 17.9%; the trigone, 12.6%; the neck, 11.1%; the ureteric orifices, 9.8%; the dome, 7.7%; and the anterior wall, 3.8%. Malignant neoplasms occurring in the neck of the bladder had a significantly poorer prognosis by survival analysis (P less than 0.05). Malignancies of the dome were found to present as higher grade lesions (P = 0.00003), and carcinoma of the ureteric orifices and lateral walls tended to be of lower grade (P = 0.02 and P = 0.05, respectively). Carcinomas of the anterior wall and dome occurred in a more elderly population (mean ages, 75.6 and 73.9 years, respectively), and carcinomas of the trigone and ureteric orifices occurred in a younger group (mean ages, 68.3 and 67.5 years, respectively). On histologic evaluation the trigone gave rise to more squamous cell carcinoma than expected (P = 0.001, 325% of expected). No distribution difference was noted among subsites with respect to sex. These data show significant differences among subsites of the urinary bladder with regard to survival, grade, histology, and age at diagnosis. 