(99m)Technetium-C595 radioimmunoscintigraphy: a potential staging tool forbladder cancer

Objectives To assess whether immunoscintigraphy using a conjugate of the an ti-MUC1 monoclonal antibody C595 and Tc-99m could be used to target transit ional cell bladder cancer after intravenous administration to patients. Patients and methods Twenty-one patients with invasive or metastatic transi tional cell carcinoma were recruited. Patients received I mg of C595 labell ed with 800 MBq Tc-99m followed by imaging at 0.5, 6 and 24 h using a combi nation of planar and single-photon emission computed tomography. Of these p atients. 14 subsequently underwent cystectomy, four underwent radiotherapy and the remaining three had histologically confirmed metastatic disease. Th e results of immunoscintigraphy were compared with surgical findings and co nventional radiology. Results There were no adverse reactions in any patient. Of the 20 patients who were found to have tumour at the time of the study, positive localizati on of antibody in tumour was apparent in 16. Of the remaining four patients . false-positive localization of antibody in presumed nodal tissue was dete cted in two. The remaining scan results were equivocal. In three patients, histologically confirmed pelvic nodal metastases that had not been detected on preoperative computed tomography were identified. Conclusion These early results show the potential of Tc-99m-C595 immunoscin tigraphy for staging bladder cancer, A larger study is needed to fully eval uate the technique.