The Intraoperative Detection of Ovarian Adenocarcinoma Using Radiolabeled CC49 Monoclonal Antibody and a Hand-Held GammaDetecting Probe

A phase II study to evaluate the safety and efficacy of the ¹²⁵I-radiolabeled anti-TAG-72 monoclonal antibody, CC49, as a component of a system for the intraoperative detection of occult ovarian cancer deposits was carried out at the University of Nebraska Medical Center. Patients entered into the study were to have surgery for evaluation of their disease status. The primary objective of this study was to determine the ability of a gammadetecting probe (GDP), the Neoprobe®1000, to intraoperatively localize sites of disease not identified by traditional surgical or radiographie evaluation. It was postulated that improved detection of cancer foci might allow for therapeutic excision or might result in an alteration of subsequent treatment. Ten patients were enrolled in the study between May 1993 and March 1994. Nine of the patients were undergoing second-look surgery after completing primary chemotherapy. The remaining patient was having surgery to assess possible cancer recurrence. All patients received an intravenous injection of2mCi/lmg ¹²⁵l-radiolabeled CC49 without complication. After a mean of 24.5 days, the patients background radiation counts were deemed low enough for accurate intraoperative cancer localization, and surgery was performed. Any visibly or palpably abnormal areas were biopsied after being evaluated with the GDP. Any areas suspicious for malignancy by GDP evaluation were also biopsied. Two patients without evident disease by radiographie or surgical examination had histologically confirmed métastases localized by the GDP. Four patients had obvious disease at surgery which was variably confirmed by the GDP; two of these patients had baseline elevations in circulating TAG- 72 antigen levels that may have affected binding of antibody to the tumor. This system of radioimmunoguided surgery was well tolerated and practical in its application, and it permitted disease detection that resulted in potentially beneficial changes in patient management.