Purpose: We examined the use of immunostaining of the Lewis X antigen in exfoliated cells from voided urine samples, cytopathology and bladder ultrasound for noninvasive detection of bladder tumors as a potential substitute for cystoscopy.
Materials and methods: A total of 260 patients were included, of whom 80 were evaluated because of irritative symptoms or hematuria and 180 were examined during followup visits after resection of bladder tumors. Voided urine samples were obtained from each patient for immunocytology and cytopathology. Bladder ultrasound and cystoscopy were performed. Biopsies were obtained whenever a bladder tumor was seen or if carcinoma in situ was suspected. Indirect immunoperoxidase staining was done on cytocentrifuge slides, using the P12 monoclonal antibody against the Lewis X antigen.
Results: Cystoscopy and biopsies revealed bladder tumors in 84 patients. Immunocytology of 1 urine sample resulted in a sensitivity of 79.8% and a specificity of 86.4%. The diagnosis of primary carcinoma in situ by immunocytology was correct in 100% of the cases. The examination of 2 consecutive urine samples detected 95.1% of the tumors. False-negative results occurred in a few cases with small, superficial, low grade tumors. Cytopathology and bladder ultrasound resulted in a sensitivity of 47.6 and 66.7%, and a specificity of 97.7 and 97.2%, respectively. The results of immunocytology of 2 urine samples were equivalent to the combination of immunocytology of a single urine sample, cytology and ultrasound.
Conclusions: Immunostaining of the Lewis X antigen is significantly more sensitive than cytopathology for the detection of low grade as well as high grade tumor cells in voided urine. Immunocytological evaluation of 2 consecutive voided urine specimens for the Lewis X antigen is the most sensitive method currently available for noninvasive detection of transitional cell tumors. This assay may replace cystoscopy for detection of bladder cancer.