Radioimmunoguided radical prostatectomy and lymphadenectomy.

Background: The feasibility of using radioimmunoguided surgery (RIGS) (Neoprobe Corp., Columbus, OH) for intraoperative detection of prostate cancer was examined in a pre-Phase I clinical study involving 10 patients having radical prostatectomy and lymphadenectomy.

Methods: Patients were injected with iodine 125-radiolabeled B72.3 monoclonal antibody, which has been shown previously to bind to TAG-72, a pancarcinoma and oncofetal antigen. At a mean of 26 days after injection, RIGS was performed with a specially designed intraoperative gamma-detecting probe.

Results: By comparing probe counts with counts of appropriate background tissues, the RIGS system successfully localized tumor to the prostate of all 10 patients. Clinically occult and histologically confirmed bilateral intraprostatic tumor was identified in three patients. One additional patient had bilateral positive intraprostatic probe count ratios with the RIGS technique; on histologic examination, tumor was identified unilaterally, and extensive high-grade prostatic intraepithelial neoplasia was found on the contralateral side. Probe count ratios were positive in the lymph nodes of three patients; two had tumor confirmed histologically.

Conclusions: The current investigation supports the feasibility of the RIGS technique and the need for additional studies.