A Kinder, Gentler Bladder Cancer Test
Jan. 16, 2001 -- A simple, painless urine test may soon help doctors tell which patients with bladder cancer are at risk for having the disease recur. That's important because such cancer reappears about 80% of the time, say researchers from Yale University, and the current method used to test for it -- which involves inserting a scope through the urethra into the bladder -- is quite uncomfortable for patients.
That method, called a cystoscopy, might become just an unpleasant memory if the Yale team's urine test continues to prove effective. The new test looks for the presence of something called survivin in the urine, says Dario Altieri, MD, professor of pathology at the Yale School of Medicine in New Haven, Conn.
Altieri explains that survivin is a natural substance that hinders "apoptosis," the body's built-in system of killing off unnecessary cells. "For this reason, survivin is very important during fetal development," Altieri says. "By inhibiting apoptosis, it helps keep cells alive."
In the case of cancer cells, which are multiplying out of control, it is not surprising that there is an excess of survivin. "The molecule helps preserve the viability of cancer cells and makes them more resistant to chemotherapy," Altieri says.
In collaboration with physicians from Yale's department of surgery, Altieri devised a strategy for exploiting this phenomenon to determine if a patient with a history of bladder cancer is at risk for having the cancer come back.
"The assumption is that if there were a tumor in the bladder, the tumor cells, which would be released in the urine, would contain the survivin molecule," he says. "We reasoned that we might be able to detect it with a simple urine test."
Their hunch appears to be borne out.
Altieri and colleagues surveyed urine samples from various groups of individuals: healthy volunteers, patients with noncancerous urinary tract disease, patients with genitourinary cancer, and patients with bladder cancer. They found that survivin was detected in the urine samples of all of the patients with new or recurrent bladder cancer, but was not found in healthy volunteers or in patients with prostate, kidney, vaginal, or cervical cancer.
The results indicate a high degree of test sensitivity, Altieri says, meaning the presence of the molecule is a strong signal a tumor is present. At the same time, however, he notes that three of the patients with noncancerous urinary tract disease, and one patient with increased prostate specific-antigen, also tested positive for survivin.
This indicates the test may not be perfectly specific for bladder cancer and could therefore lead to false-positive results.
"Clearly, this study needs to be expanded in a much larger population," Altieri cautions. "We are following the three individuals who had a false-positive test and have found after six months had elapsed, that one of them did develop bladder cancer."