New Test Improves Detection of Bladder Cancer

CHICAGO -- Testing for a certain protein in urine was found to increase
the accuracy for diagnosis of bladder cancer, according to a study in
the February 16 issue of JAMA, a theme issue on medical applications of
biotechnology.

Bladder cancer is the fifth most common malignancy in the United
States, according to background information in the article. Early
detection improves prognosis, treatment options, and quality of life.
Although the 5-year survival rate is 95 percent when tumors are
detected while they are confined to the mucosa (membrane), up to 25
percent of the approximately 60,000 bladder tumors predicted to be
diagnosed this year will be detected after they have become invasive or
metastatic, which lowers 5-year survival to approximately 48 percent
and 10 percent, respectively. As a result, 13,000 Americans will die of
bladder cancer this year.

A combination of methods is used for diagnosis of bladder cancer
because no single procedure detects all malignancies. Urine tests are
frequently part of an evaluation, but have either been nonspecific for
cancer or required specialized analysis at a laboratory.

H. Barton Grossman, M.D., of M.D. Anderson Cancer Center, Houston, and
colleagues investigated whether a new, point-of-care, noninvasive
urine-based test for the protein NMP22 proteomic marker could improve
detection of bladder cancer.  The researchers compared the ability of
this test to detect cancer with that of urine cytology (cells), which
must be analyzed in a clinical laboratory.  The study included 23
academic, private practice, and veterans' facilities in 10 states which
enrolled 1,331 patients at elevated risk for bladder cancer (history of
smoking and certain symptoms) from September 2001 to May 2002.
Patients at risk for malignancy of the urinary tract provided a urine
sample for analysis of NMP22 protein and cytology prior to cystoscopy
(visual examination of the bladder using a special instrument that is
passed through the urethra).

Bladder cancer was diagnosed in 79 patients.  "We found that the NMP22
test is a useful adjunctive tool in the evaluation of patients at risk
for bladder cancer and that it identified several malignancies missed
by initial cystoscopy. Specificity of the NMP22 test was lower than for
cytology (85.7 percent vs. 99.2 percent), but sensitivity was
significantly greater (55.7 percent vs. 15.8 percent), with test
results available during the patient visit," the authors write. "The
proteomic marker detected 4 cancers that were not visualized during
initial cystoscopy, including 3 that were muscle invasive and 1
carcinoma in situ."

According to the article, the average Medicare reimbursement for voided
cytology is approximately $56, compared with $24 for the NMP22
point-of-care assay.

"In conclusion, the NMP22 assay may be a useful adjunct to cystoscopy
for diagnosing bladder cancer. Studies in different patient populations
are necessary to further define the role of this assay in patients with
risk factors and symptoms suggestive of possible bladder cancer," the
researchers write.