What biomarker testing is recommended for locally advanced Bladder Cancer

Biomarker Testing for Locally Advanced Bladder Cancer

Based on the NCCN Guidelines for Bladder Cancer (2025), here's what you need to know about biomarker testing for locally advanced disease:

Key Recommendation

For locally advanced unresectable or metastatic bladder cancer, the NCCN Panel recommends somatic tumor testing (genetic testing of the cancer cells themselves) for all patients at the time of initial diagnosis and again if the disease recurs.

Specific Biomarkers to Test

Your oncology team should look for:

1. FGFR3 Alterations (Priority)

• What it is: A genetic change in the FGFR3 gene that some bladder cancers have
• Why it matters: FGFR3 mutations can be targeted with FDA-approved drugs like erdafitinib, which may be treatment options for your specific case
• Testing method: Reverse transcriptase polymerase chain reaction (RT-PCR) in a certified laboratory

2. HER2 Status (Priority)

• What it is: A protein that appears on some cancer cells
• Why it matters: HER2-positive bladder cancers may respond to targeted therapies like fam-trastuzumab deruxtecan (FDA-approved)
• Testing method: Immunohistochemistry (IHC) - a staining technique that shows if HER2 is present

3. Microsatellite Instability (MSI-H) and Mismatch Repair (MMR) Status

• What they are: Tests that show how well your cancer cells can repair DNA errors
• Why it matters: MSI-H/MMR-deficient cancers may respond better to immunotherapy checkpoint inhibitors
• Clinical significance: This information helps determine which treatment approaches might work best

4. Broader Genomic Testing (Often Recommended)

The NCCN Panel notes that a larger genetic panel may be preferred because:

• It can identify rare mutations that have approved therapies
• It helps determine eligibility for clinical trials
• Bladder cancer is highly mutated (ranked 3rd among all cancers for genetic changes)
• Studies show 93% of advanced bladder cancers have at least one clinically relevant genetic alteration

Important Clinical Context

According to NCCN Guidelines, these tests should be performed in CLIA-certified laboratories (Clinical Laboratory Improvement Amendments-approved), which means they meet strict quality standards for complex molecular testing.

Questions to Ask Your Oncologist

1. Have you ordered somatic tumor testing for my cancer? If not, why not?
2. Which specific biomarkers will be tested? (Make sure FGFR3 and HER2 are included)
3. Will you do a broader genomic panel or just targeted testing? What are the pros/cons for my situation?
4. When will I have these results, and how will they affect my treatment plan?
5. Are there any clinical trials I might be eligible for based on my biomarker results?
6. What do my specific results mean for treatment options available to me?

Why This Matters for Your Care

Biomarker testing is crucial because it:

• Identifies which targeted therapies your cancer might respond to
• Helps your doctor personalize your treatment plan
• May open doors to clinical trials
• Provides prognostic information (information about how the disease may progress)

According to the NCCN Guidelines, testing should be done early at diagnosis to prevent delays in getting you the right treatment.

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This information is for educational purposes only. Always consult your healthcare team for personalized medical advice and decisions.