DETECTION OF BLADDER-TUMORS BY IMMUNOSTAINING OF THE LEWIS-X ANTIGEN IN CELLS FROM VOIDED URINE

Objectives. A study was made to determine the sensitivity and specificity of immunostaining of the Lewis X antigen in exfoliated urothelial cells from voided urine, for the detection and surveillance of bladder tumors. Methods. Three consecutive voided urine specimens were obtained from 101 patients, 78 of whom were under surveillance because of a history of bladder tumors, and 23 were being evaluated because of hematuria or irritative urinary symptoms. Indirect immunoperoxidase staining of two urine samples was done on cytocentrifuge slides, using the P12 monoclorial antibody against the Lewis X antigen. The diagnosis of the presence of a urothelial tumor was made if more than 5% of the cells showed a typical red-brown staining. Cytopathologic examination of the third urine specimen was done according to Papanicolaou. Each patient underwent cystoscopy, and biopsies were obtained whenever there was endoscopic evidence of bladder tumors or carcinoma in situ. Results. Cystoscopy and biopsies revealed transitional cell carcinoma in 32 patients, whereas 69 patients had no evidence of bladder tumors. Immunocytology of one urine sample showed true-positive results in 26 of the 32 patients with bladder tumors, corresponding to a sensitivity of 81.25%. When two samples were examined, a sensitivity of 97% and a specificity of 85.5% were obtained. When the results of cytology and immunocytology were combined, sensitivity reached 100%. High-grade and low-grade transitional cell tumors were detected with equal efficiency. Conclusions. The use of P12 monoclonal antibody for evaluation of Lewis X reactivity in cytologic preparations from multiple voided urine specimens can improve the sensitivity of noninvasive detection of bladder cancer. The technique may ultimately replace cystoscopy in monitoring therapeutic response and tumor recurrence.