111Indium-capromab pendetide in the evaluation of patients with residual or recurrent prostate cancer after radical prostatectomy

Purpose: Standard diagnostic methods are limited for detecting distant metastases in patients with prostate cancer in whom the only evidence of disease after radical prostatectomy is a detectable prostate specific antigen (PSA) level. We evaluated the role of immunoscintigraphy with the radiolabeled monoclonal antibody, (111)indium (In-111)-capromab pendetide, to differentiate between local and distant recurrence in this patient population. Materials and Methods: We enrolled 183 men who had undergone radical prostatectomy in whom PSA later increased. Gamma camera images were acquired twice after infusion of a single dose of In-111-capromab pendetide. Results: Immunoscintigraphy revealed disease in 108 of 181 patients (60%) with interpretable scans. The antibody was localized most frequently to the prostatic fossa (34% of the cases), abdominal lymph nodes (23%) and pelvic lymph nodes (22%). Of the 181 men the scan localized the antibody outside the prostatic fossa in 42%. Half of the positive localizations in the fossa were confirmed by biopsy. Conclusions: These findings suggest that immunoscintigraphy with In-111-capromab pendetide can assist in determining the extent of disease in patients who have increasing PSA after prostatectomy.