THE ROLE OF RADIOIMMUNOSCINTIGRAPHY AND COMPUTED-TOMOGRAPHY SCAN PRIOR TO REASSESSMENT LAPAROTOMY OF PATIENTS WITH OVARIAN-CARCINOMA - A PRELIMINARY-REPORT

BACKGROUND. Accurate evaluation of patients with ovarian carcinoma who have completed primary therapy often requires surgical exploration. R adioimmunoscintigraphy (RIS) represents an evolving technique that may allow noninvasive detection and localization of persistent or recurre nt disease in these patients. METHODS. Our prospective, blinded study enrolled patients with normal CA 125 levels and no clinical evidence o f disease after primary cytoreductive surgery and cytotoxic chemothera py for ovarian carcinoma. Each patient underwent RIS using (111)Indium -satumomab pendetide (labeled antibody B72.3 to the tumor-associated a ntigen TAG-72) and abdominal/pelvic computed tomography (CT) prior to reassessment laparotomy. RESULTS. Twenty patients were enrolled from J anuary 1994 to January 1995. Two patients with negative RIS scans refu sed reassessment laparotomy and were without evidence of disease >15 m onths from the study. Twelve of the remaining 18 patients (66.7%) had histologically proven disease at reassessment laparotomy. RIS images i ndicated the presence of disease in all 12 patients, whereas CT scans detected disease in only 2 patients. In three of five patients, biopsy -proven microscopic disease (no gross disease at the time of laparotom y) was found only in specimens obtained by RIS-directed biopsies. RIS was superior to CT in sensitivity (100% vs. 16.7%), accuracy (72% vs. 33%), and negative predictive value (100% vs. 28.6%) (P < 0.005). CONC LUSIONS. Routine use of CT is of limited value in the assessment of ov arian carcinoma patients with negative physical examinations and norma l CA 125 levels. With its high level of sensitivity and negative predi ctive value, RIS may play a role in the detection of persistent diseas e in this population and aid in the classification of patients into th ree distinct groups: those with gross residual disease, small volume o r microscopic disease, and no disease. Separation of this heterogenous group without surgery may help guide subsequent consolidation therapy . However, attaining a high level accuracy with RIS, depends on optimi zing the method of image acquisition, the timing of scans, and the rec onstruction of data. (C) American Cancer Society.