Detecting lymphatic metastases from prostatic carcinoma: superiority of CT.

CT scanning was performed on 29 consecutive patients with clinically localized prostatic carcinoma (stage A or B). Bipedal lymphangiography was performed in 12 cases. Histologic confirmation was obtained in 15 cases (pelvic lymphadenectomy in 12 and positive percutaneous needle biopsy in three). In these 15 proven cases, the overall accuracy of CT was 93% with one false positive and no false negatives. Lymphangiography was far less accurate (55%) with two false positives and three false negatives in 11 proven cases. The greater accuracy of CT resulted primarily from its ability to detect abnormal nodes in the pelvis, particularly hypogastric nodes, which are rarely opacified by lymphangiography. Preliminary experience suggests that CT is superior to lymphangiography in detecting early lymphatic spread from prostatic carcinoma in the pelvis. In the future, CT-guided percutaneous needle biopsy should be useful for documenting metastases in these patients.