No abstract

Forty-five patients known or suspected to have transitional cell carcinoma of the urinary bladder underwent intravesical administration of either AUA1 tumor-associated monoclonal antibody or 11.4.1. nonspecific monoclonal antibody. Antibodies were radiolabeled with iodine-131, diluted in 50 ml normal saline and remained in the bladder for up to 1 h. During cystoscopy or transurethral resection of the tumor, tissue samples were taken from normal and malignant areas and were counted for radioactivity in a gamma counter. Blood samples were also measured for radioactivity. Mean uptake of AUA1 at 2, 20, 40 and 60 h after administration (expressed as 10(3) x percentage of injected dose/gram of tissue) was: 1.77 +/- 3.2, 1.28 +/- 1.67, 0.72 +/- 0.94 and 0, respectively in the tumor and 0.79 +/- 0.83, 0.14 +/- 0.34, 0.033 +/- 0.06 and 0 in normal tissue. Mean uptake of 11.4.1 at 2 and 20 h was: 0.47 +/- 0.42 and 0.018 +/- 0.015, respectively, in tumor and 0.2 +/- 0.19 and 0.013 +/- 0.002 in normal samples. No remarkable radioactivity was found in blood samples. Conventional and immunoperoxidase staining were also performed. Mean uptake of AUA1 by the tumor increased as the degree of tumor differentiation decreased. Our findings indicate that intravesical administration of AUA1 results in selective immunolocalization of AUA1 in intermediate and high-grade transitional cell carcinoma. This may allow the development of a new method for bladder carcinoma treatment or prophylaxis against recurrence.

The monoclonal antibody AUA1, labelled with 2 or 3 mCi iodine-131, was administered intravesically to 11 patients with known or suspected bladder carcinoma and was kept in the bladder for 1 h. All patients underwent immunoscintigraphy of the bladder at 2 h and three patients also at 20 h after instillation. Conventional histological and immunohistochemical examinations were performed on tissue samples from tumour and normal areas taken during cystoscopy, carried out 24-h after the instillation. Transitional cell carcinoma of the bladder was present in nine patients whereas dysplastic and normal urothelium was found in the remaining two patients, respectively. Six out of nine tumours were successfully imaged at the 2-h scan. Normal urothelium showed no uptake while dysplastic urothelium was positive on imaging. Successful detection was correlated with size and grade of tumour in almost all cases. Tumors with a diameter of 1 cm or less were not detected. Four out of five grade II tumours and two out of three grade III tumours were detected with this method. The method is a promising one although further studies using more suitable isotopes and/or monoclonal antibodies are required to increase its sensitivity.