Evaluation of the telomeric repeat amplification protocol (TRAP) assay for telomerase as a diagnostic modality in recurrent bladder cancer

There is a need for the identification of an accurate test for the detection of recurrent bladder cancer. In this study, we evaluate the telomeric repeat amplification protocol (TRAP) assay for detection of telomerase as a potential new method for bladder cancer detection and compare it to voided urine cytology. A urine sample and a bladder wash were obtained from 63 patients with a history of bladder cancer. Cytological evaluation was performed on voided urine, and the TRAP assay was performed on voided urine and bladder wash. The overall clinical sensitivity of the TRAP assay, as defined by the ability to identify correctly the patients with pathologically confirmed bladder cancer, was 35% in voided urine and 50% in bladder wash, whereas the overall clinical sensitivity of voided urine cytology was 71%. The sensitivity of voided urine cytology for the papillary and noninvasive tumors (T(a)) was 50%, compared to 92% for the superficially invasive tumors (T₁), 62% for the muscle-invasive tumors (T₂₊), and 100% for the high-grade flat carcinoma in situ (T(is)). The clinical sensitivity of the TRAP assay using voided urine was 46% for T(a), 50% for T₁, 18% for T₂₊, and 20% for T(is). The sensitivity of the TRAP assay in T(a) disease was similar to that of cytology (50% for cytology versus 46% for the TRAP assay). There was a strong association between the total number of exfoliated malignant cells and the sensitivity of the assay. The sensitivity of the TRAP assay in bladder washes was 44% for T(a), 67% for T₁, 46% for T₂₊, and 43% for T(is). The TRAP assay is reproducible, highly specific, and not dependent on the expertise of the cytopathologist. These results suggest that this assay should be further investigated as a diagnostic tool for bladder cancer.