Telomerase may yield promising bladder cancer marker

Forlì, Italy-A noninvasive bladder cancer detection test that relies on measuring telomerase activity could offer higher sensitivity and specificity rates than other commonly used noninvasive tests, according to a new study from Italy.

"It looks like we are looking at something with about 90% sensitivity and 90% specificity. That is about 10 points higher than any other test that is out there," said Dr. O'Donnell, who was not involved with this study.

The Italian researchers conducted a case-control study of 218 men: 84 healthy individuals and 134 who were patients at the first diagnosis of histologically confirmed bladder cancer. The researchers took urine samples from all patients and processed the samples for cytologic diagnosis and telomeric repeat amplification protocol (TRAP) assay. Then they compared the TRAP assay, which was performed in a blinded fashion, with urine cytology for the ability to detect bladder cancer.

Using a cutoff value of 50 arbitrary enzyme units, the TRAP test demonstrated a sensitivity of 90% and specificity of 88%, as reported in JAMA (2005; 294:2052-6). In a subgroup of patients 75 years of age or younger, the specificity increased to 94%.

"The sensitivity of the TRAP test was similar for all grade tumors. For grade 1 tumors, the sensitivity was 93%; for grade 2 tumors, the sensitivity was 87%; and for grade 3 tumors, the sensitivity was 89%," said senior author Daniele Calistri, PhD, of the division of oncology and diagnostics, Morgagni-Pierantoni Hospital, Forlì, Italy.

The test's predictive value was equally high in study participants who were free of cancer and in those who had low-grade tumors, the data showed.

"... [I]t could be a good marker for high-risk screening groups," Dr. Calistri told Urology Times. "Furthermore, it shows a high sensitivity for the diagnosis of low-grade tumors that can escape detection during cytological examination. Results are usually available in 2 to 3 days."

Urine telomerase is a simple test because patients need only to produce a urine specimen.

"It is that readout that is the quantitative measurement of this enzyme in the urine. Telomerase is an enzyme that is essentially only present in cancer cells and cells with unlimited growth potential."