IMMUNOSTAINING OF LEWIS-X IN CELLS FROM VOIDED URINE, CYTOPATHOLOGY AND ULTRASOUND FOR NONINVASIVE DETECTION OF BLADDER-TUMORS

Purpose: We examined the use of immunostaining of the Lewis X antigen in exfoliated cells from voided urine samples, cytopathology and bladd er ultrasound for noninvasive detection of bladder tumors as a potenti al substitute for cystoscopy. Materials and Methods: A total of 260 pa tients were included, of whom 80 were evaluated because of irritative symptoms or hematuria and 180 were examined during followup visits aft er resection of bladder tumors. Voided urine samples were obtained fro m each patient for immunocytology and cytopathology. Bladder ultrasoun d and cystoscopy were performed. Biopsies were obtained whenever a bla dder tumor was seen or if carcinoma in situ was suspected. Indirect im munoperoxidase staining was done on cytocentrifuge slides, using the P 12 monoclonal antibody against the Lewis X antigen. Results: Cystoscop y 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 immunocytolog y was correct in 100% of the cases. The examination of 2 consecutive u rine samples detected 95.1% of the tumors. False-negative results occu rred in a few cases with small, superficial, low grade tumors. Cytopat hology 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. C onclusions: Immunostaining of the Lewis X antigen is significantly mor e sensitive than cytopathology for the detection of low grade as well as high grade tumor cells in voided urine. Immunocytological evaluatio n of 2 consecutive voided urine specimens for the Lewis X antigen is t he most sensitive method currently available for noninvasive detection of transitional cell tumors. This assay may replace cystoscopy for de tection of bladder cancer.