Radioimmunoguided breast surgery using radiolabeled antibody NR-LU-10 Fab:A pilot study

Aim and background: Radioimmunoguided surgery using radiolabeled NR-LU-10 F ab was evaluated as a method of intraoperative breast cancer detection. Methods: Breast cancer patients were injected intravenously with I-125 (74 MBq) labeled NR-LU-IO Fab (5 mg) and then underwent tumor excision 2, 4 or 7 days later, during which time the gamma detector probe was used to evalua te the primary tumor for evidence of radioactive uptake. Results: Intraoperative probing revealed tumor localization in 7 of 10 pati ents (70%), Gamma probe counts of the excised tumor were elevated in all pa tients, although high counts in surrounding non-malignant tissue obscured t he ability to detect the tumor in vivo in 3 patients. One patient with bila teral breast cancer was found to have a separate focus of occult tumor in e ach breast using the gamma detector probe. Conclusions: Radiolabeled NR-LU-10 Fab possesses favorable pharmokinetics a nd tumor-binding ability as a targeting agent. However, binding to non-mali gnant tissue limits its role in the intraoperative evaluation of tumor marg ins in breast cancer patients. Its role in other malignancies should be exp lored.