Urine test helps detect 99 percent of recurring bladder cancers
Results available in physician’s office
A simple urine test that can be interpreted in a doctor’s office can help detect nearly all recurrences of bladder cancers with a higher accuracy rate than conventional laboratory analysis of urine tests. The BladderChek test, used in conjunction with a diagnostic scope, detected 99 percent of recurring bladder cancers, according to a study in the Jan. 18 issue of JAMA.
"This is good news for patients. If you have been treated for bladder cancer and are being monitored for recurrence, the accuracy of your diagnosis is extremely important. We depend on the urine test to show us whether there’s a possibility of cancer that we’re not seeing with the scope. If we say there’s no recurrence of cancer, we want to be right," says author Barry Stein, MD, a professor of urology at Brown Medical School and surgeon-in-chief of urology at Rhode Island Hospital, a participating site in the study.
The BladderChek test – which requires four drops of urine – detects elevated levels of the nuclear matrix protein NMP22, an indication of cancer even at early stages of the disease. A doctor or nurse can read the results in 30 to 50 minutes.
"You know the answer before the patient is out of your office," Stein says. "If the result is positive, and you didn’t see anything from the cystoscopy, you would check to see if you missed something."
No single procedure is completely effective in detecting recurring bladder cancer, so physicians use a combination of methods – typically cystoscopy and a urine cytology test. Cystoscopy, a minimally invasive procedure performed in a physician’s office, enables physicians to view the wall of the bladder through a scope. However, it may not detect very small tumors or tumors in the muscle or upper tract. So in conjunction with the scope, physicians rely on cytology, a clinical analysis of a urine sample. The process can take a week or more, and requires expert interpretation. The analysis identifies changes in intact cells, but its sensitivity is dependent on the size and shape of the tumor.
In this study, 668 patients with a history of bladder cancer provided a urine sample before undergoing cystoscopy during follow-up visits with their physician. The urine sample was analyzed with urine cytology, and with the BladderChek test. Bladder cancer was identified in 103 patients. Cytoscopy alone detected 94 cancers, and the BladderChek test detected 8 of 9 cancers that were not seen through the scope – 7 of them life-threatening. The urine cytology only detected 3 of the 9 cancers.
Cystoscopy alone detected 91.3 percent of cancers. When cystoscopy was used with conventional urine analysis, the detection rate was 94.2 percent; when it was used with the BladderChek test, detection was 99 percent.
An accurate urine test could reduce the number of cystoscopies a patient undergoes, Stein says. While not painful, the procedure can be uncomfortable. By contrast, the BladderChek test is similar to a pregnancy test and gives objective results – if cancer is detected, a purple line appears.
The study demonstrates that one day a simple urine test might replace cystoscopies, Stein says.
"I’m not saying any one study gives you the confidence to change 100 years of tradition," Stein says. "We need to do further research. But if a test is developed that is effective as a stand-alone, that would be a real benefit."
Nicole Gustin | EurekAlert!