MULTICENTER RADIOIMMUNOSCINTIGRAPHIC EVALUATION OF PATIENTS WITH PROSTATE CARCINOMA USING IN-111 CAPROMAB PENDETIDE

BACKGROUND. Optimum therapy for prostate carcinoma patients requires a ccurate staging, but computed tomography (CT) and magnetic resonance i maging (MRI) have limitations as methods for detecting soft tissue met astases. In this study, radioimmunoscintigraphy (RIS) was evaluated fo r its ability to identify sites of metastatic disease in lymph nodes. METHODS. RIS was evaluated in 51 prostate carcinoma patients at high r isk for metastatic disease. An intravenous infusion of indium-111 capr omab pendetide tvas given, followed by nuclear medicine imaging on two separate dates. Bilateral, open pelvic lymph node dissection was perf ormed with additional exploration and biopsy of scan positive extrapro static regions. Histologic evaluation of removed tissue confirmed the accuracy of RIS. In addition, results were compared with other standar d methods for diagnosing patients prior to surgery. RESULTS. Nineteen patients (37%) had evidence of lymph node involvement with RIS. Fiftee n of the 19 positive patients had pathologic evidence of cancer in the biopsied lymph nodes. Sensitivity, specificity, accuracy, and the pos itive predictive value for detection of extraprostatic disease were 75 %, 86%, 81%, and 79%, respectively. CT, MRI, and ultrasound of the pel vis demonstrated a combined accuracy of only 48% in detecting lymph no de disease. Twenty-five previously undetected sites were deemed positi ve with RIS. Fourteen of these were biopsy-proven tumor sites, seven w ere probable tumor sites, and four were assumed to be false-positive. CONCLUSIONS. RIS had an impact on patient management through its detec tion of occult disease in more than 50% of prostate carcinoma patients studied, and it provided information concerning the likelihood that l ymph node metastases would be found during surgery. Cancer 1998;83:739 -47. (C) 1998 American Cancer Society.