Objectives: To study the diagnostic performance of the ImmunoCyt test in patients in follow-up for superficial urothelial cell carcinoma (UCC) of the bladder.
Methods: Voided urine samples were collected from all included patients. Samples were processed with the ImmunoCyt test. The ImmunoCyt slides were scored under a fluorescence microscope by 3 observers. The ImmunoCyt test was considered positive if one or more observers scored the test positive. Urethrocystoscopy (and additional histologic examination in the case of suspicious cystoscopic findings) was used as the reference standard. To investigate the validity of ImmunoCyt, sensitivity, specificity, positive predictive value, negative predictive value, area under the receiver operating characteristic curve, and diagnostic odds ratios were determined. To investigate the reproducibility of ImmunoCyt, kappa values (measure of agreement) were computed. The observers' findings were analyzed in pairs.
Results: One hundred four patients in follow-up after primary superficial UCC of the bladder were included. Samples of 18 patients had to be excluded because of low cellularity (ie, insufficient assessable urothelial cells). Tumor recurrence was found in 22 of the remaining 86 patients (17 pTa, 3 pT1, 1 carcinoma in situ, 1 pT2 or higher). The test had a sensitivity of 50%, specificity of 73%, positive predictive value of 39%, and negative predictive value of 81%. The diagnostic odds ratio was 2.8 (95% confidence interval 1.0 to 7.5). The area under the curve for the different observers varied between 0.54 and 0.60. The kappa values were low (0.05 to 0.45), representing high interobserver variability.
Conclusions: The promising results from other studies could not be confirmed in this specific group of patients in follow-up for superficial UCC of the bladder. The validity of ImmunoCyt was insufficient to justify the omission of cystoscopy in patients in follow-up for superficial UCC.