Bladder Cancer Test Looks Promising
Wednesday, October 26th 2005, 10:53 am
By: News On 6
CHICAGO (AP) _ A simple, experimental urine test that checks for an enzyme that fuels tumors is an effective way to detect bladder cancer in early, curable stages, Italian researchers say.
A handful of similar tests that check for different substances are already on the market, but the new test is more accurate, said Daniele Calistri, the study's senior author and a cancer researcher at Morgagni-Pierantoni Hospital in Forli, Italy.
``Another important advantage of this test is its ability to identify low-grade (less aggressive) tumors, which often escape detection,'' the researchers said in a report published in Wednesday's Journal of the American Medical Association.
Early diagnosis is a challenge in bladder cancer, which often grows rapidly. Blood in the urine is a common symptom, but it also can signal less serious conditions and patients frequently dismiss it until the disease has progressed, said Dr. Edward Messing, urology chairman at the University of Rochester Medical Center.
``It's potentially a very useful test,'' said Messing, calling the study ``the best results I've ever seen,'' although not definitive. He was not involved in the research.
The study involved 134 male bladder cancer patients and 84 healthy men. The test correctly identified cancer in 90 percent of the patients and ruled it out appropriately in healthy men almost as often.
Bladder cancer occurs in men much more often than women; whites, smokers and people aged 65 and older also are disproportionately affected. More than 60,000 new cases are diagnosed each year in the United States alone. About 20 percent of patients die each year but survival chances are good with early detection, the researchers said.
The new test detects urine levels of telomerase, or what is sometimes called the ``immortalizing enzyme'' because it enables cancer cells to keep growing indefinitely. Telomerase is present in almost all human cancer cells but only rarely in non-cancerous cells, and burgeoning research is investigating ways to use it as a target for both diagnosing and treating cancer, said Jerry Shay, a cancer researcher at the University of Texas Southwestern Medical Center in Dallas.
Telomerase appears relatively late in some cancers but early in bladder cancer, making it a good target for early detection, he said.
The Italian researchers said larger studies are needed but that they envision the test as a potential screening tool for people at high risk for bladder cancer, including smokers and those with symptoms. The cancer is not common enough to recommend universal screening, asid the researchers whose goal is to use the test to help spot patients who need more invasive testing.
Traditional testing includes checking urine specimens for abnormal-looking cells, but that misses many cancers, Shay said.
An invasive test called cystoscopy is more definitive and involves visually inspecting the bladder through a catheter and removing suspicious cells for examination.
Newer detection methods include testing urine for certain proteins, with results available while patients wait in the doctor's office. These typically don't rule out the need for more invasive testing.
The telomerase test is more accurate but takes two to three days to get results, Calistri said.