Computed tomography in the evaluation, staging, and therapy of carcinoma of the bladder and prostate.

Computed tomography was performed in 24 patients with bladder carcinoma, 29 patients with prostate carcinoma, and one patient with simultaneous bladder and prostate carcinoma. In nine patients (16%), the stage of the carcinoma would have been underestimated based on CT alone. Six of these nine patients had only microscopic or laboratory evidence (elevated serum acid phosphatase level) of more widespread disease than what was demonstrated by CT. The overall accuracy of pelvic lymph node evaluation by CT was 79% in 34 patients. The 21% inaccuracy arises from five false-negative cass in which there was microscopic involvement within normal-sized nodes (4 patients) or only minimally enlarged (2.0 cm or less) nodes (1 patient), and two false-positive cases related to benign changes in nodes. CT was unable to differentiate Stage A, B1, and B2 bladder tumors. CT was used in planning portals for 16 patients who underwent external beam radiation therapy. CT was also used to measure the volume of the prostate prior to placement of 125I seeds for therapy, and to assess the positioning of the seeds.