Frequency of coexistent disease at CT in patients with prostate carcinoma selected for definitive radiation therapy: is limited treatment-planning CT adequate?

PURPOSE: To document the frequency of clinically important coexistent disease depicted at contrast material-enhanced abdominal and pelvic computed tomography (CT) in patients undergoing definitive radiation therapy for prostate carcinoma, as such lesions might be missed at limited nonenhanced treatment-planning CT. MATERIALS AND METHODS: Of 133 consecutive patients with prostate carcinoma who were referred to the radiation oncology division between January 1, 1994, and December 31, 1996, 77 underwent definitive radiation therapy that required either contrast-enhanced abdominal and pelvic CT (n = 67) or contrast-enhanced pelvic CT (n = 10). Results of these studies were reviewed and retrospectively categorized. RESULTS: Forty-eight (62%) of the 77 patients had either negative studies or minor abnormalities that did not require further follow-up. Only two patients (3%) had major abnormalities that required intervention. Five patients (6%) had new findings of clinically important coexistent disease, but no intervention was required. CONCLUSION: The incidence of clinically important coexistent disease in patients with prostate carcinoma who are referred for definitive radiation therapy is low. Therefore, contrast-enhanced abdominal and pelvic CT in addition to treatment-planning CT is of limited value.