Brian Rini, MD
While biomarker-based tools designed to guide the diagnosis and treatment of prostate cancer are emerging at an extraordinarily rapid rate, they are not exploding in the same practice-changing way in all genitourinary cancers.
The development of molecular tests for bladder, renal, and testicular cancers is still in its infancy, but some tests have already reached the market, and doctors may want to consider the pros and cons associated with their use—while keeping an eye on promising biomarkers that could lead to the development of additional tools.
So far, most such tests in these disease states are focused in the area of bladder cancer. Some are diagnostic, while others are aimed at monitoring response to treatment. Meanwhile, in renal and testicular cancers, scientists are exploring a number of different biomarkers that may eventually provide guidance in both diagnosis and patient response to treatment.
Brian Rini, MD, a professor of Medicine at the Cleveland Clinic who specializes in genitourinary malignancies, is aware of that research, but says the clinical utility of biomarkers is less proven than in prostate cancer.
“These are four very different diseases. They are geographically related but quite different,” he said of prostate, bladder, renal, and testicular cancers. “In prostate cancer, there are some molecular tests around diagnosis, but other GU cancers really don’t have as much of an issue with diagnosis. The issue of overdiagnosis is not as big in the non-prostate cancers. As a result, if there are useful biomarkers in bladder, renal, or testicular cancers, they will be in matching specific drugs to specific patients, not so much diagnostic.”Bladder Cancer
Bladder cancer is typically diagnosed by checking urine microscopically for the presence of blood via urinalysis, looking for abnormal cells via urine cytology, and/or through imaging and cystoscopy, according to the US Health and Human Services (HHS) in a report by its Effective Health Care Program. The report explores the research protocol for a planned review of “Emerging Approaches to Diagnosis and Treatment of Non-Muscle-Invasive Bladder Cancer.”1
Biopsies for bladder cancer are not as difficult to interpret, and any lesion that exists can usually be visualized on cystoscopy, so additional diagnostic tests are not always considered necessary in the disease, for which there are no targeted treatments, Rini said.
“For bladder cancer, starting with non-muscle invasive disease, there are a number of urine cytology tests,” he noted. “Regular cytology would just look for cancer cells. Urine cytology, classically, is not always straightforward: The cells can look abnormal, but it’s hard to tell if they’re cancerous. There have been a number of assays that have attempted to develop other, more sensitive ways to look at cells that come out of that urine to determine if the patient has bladder cancer or recurrent bladder cancer, and there are some on the market.”
The HHS report cites a handful of urine-based molecular diagnostic tests that have been approved by the FDA for the diagnosis of bladder cancer or to guide the treatment of the disease, and some additional tests are also available.
Among FDA-approved tests, BTA stat
(Polymedco) looks for bladder tumor-associated antigen (BTA) in office settings while sister product BTA TRAK identifies BTA in a laboratory; Alere’s NMP22 Test is an enzyme immunoassay that identifies nuclear mitotic apparatus protein in urine, and sister product Alere NMP22 BladderChek Test is a quick way to identify nuclear matrix protein 22 in-office; the Visys UroVysion Bladder Cancer Kit (Abbott Molecular) looks for chromosomal abnormalities via fluorescence in situ hybridization; and, according to HHS, ImmunoCyt (Scimedx) relies on monoclonal antibodies “to test for CEA and glycoproteins using an immunofluorescent technique.”
The CxBladder test (Pacific Edge Diagnostics USA), which does not require FDA approval, looks for five specific mRNA biomarkers. CertNDx (Physicians Choice Laboratory Services), also not approved by the FDA, is an assay of three tests: It uses DNA, immunohistochemistry, and protein biomarkers to assess hematuria, conduct molecular grading, and monitor recurrence, according to a description on the website of CGS Administrators, LLC, which provides Medicare-related services (http://tinyurl.com/n9sqvlg).
Investigated as possible alternatives to cytoscopy have been diagnostic cytology tests looking for fibroblast growth factor receptor 3; cytokeratin fragments such as CYFRA 21-1, TPA, and TPS; survivin; telomerase; vascular endothelial growth factor; aurora kinase; metalloproteinases MMP-2 and MMP-9; carcinoembryonic antigen; and mucin glycoproteins, the HHS states.