Radioscintiscanning of prostate cancer

Radioscintiscanning of the prostate has been unsuccessfully attempted in the past 25 years. 65 Zinc was an early possibility could not provide satisfactory clinical images. Although cellular secretory products of the prostate, such as acid phosphatase and prostatic specific antigen (PSA), were labeled with radioisotopes, final results did not yield acceptable outcomes. More recently, a monoclonal antibody (MoAb), 7E11‐C5, to the membranes of the LNCaP (prostate cancer) cell line been developed and radiolabeled with III In. This agent, designated as CYT‐356, has successfully undergone human Phase I and II trials in which suitable radioimmunoscintography was achieved detecting prostate cancer foci in the prostate, pelvic lymph nodes, bones, and soft tissues. Generally acceptable sensitivity (>50%) and specificity (>90%) levels have been observed in the initial trials, suggesting a useful role for preoperative evaluation and follow‐up for post‐operative pelvic recurrence or other metastases. Two national Phase III trials are about to be completed in addition repeat administration study. The epitope detected by MoAb 7E11‐C5 or CYT 356 has recently been shown to be present in normal male serum, seminal fluid, and benign prostate enlargement and in higher levels in clinically advanced prostate cancers, Stages C, D1, and D2 (T2‐T3, T4). A second‐generation MoAb to CYT‐356 (7E11‐C5.3)‐defined antigen has been developed and is being tested as a potential prostate cancer serum marker. Cancer 1995;75:1819–22.