This prospective observational study evaluates a blood-based circulating tumor DNA (ctDNA) test in patients with muscle-invasive bladder cancer or upper tract urothelial cancer. ctDNA consists of small fragments of tumor DNA that can sometimes be detected in the blood.
In this study, DNA from tumor tissue obtained during routine diagnostic or surgical procedures will be analyzed to identify tumor-specific mutations. Blood samples collected during routine clinical care will then be tested to determine whether the same mutations can be detected in plasma ctDNA.
The main purpose is to assess how well the internally developed ctDNA assay detects tumor-specific mutations compared with tumor tissue sequencing. The study will also explore whether ctDNA results after treatment are associated with recurrence or remission during two years of follow-up, and whether changes in ctDNA levels during treatment are associated with pathological response.
This study does not assign participants to a treatment and does not require additional blood draws beyond routine care. Treating physicians will remain blinded to ctDNA results during the study, so the test results will not influence clinical decisions.
Age 18 years or older.
Histologically confirmed muscle-invasive bladder cancer or suspected muscle-invasive upper tract urothelial carcinoma, stage T2 or higher.
Availability of tumor tissue from transurethral resection of bladder tumor, ureteroscopic biopsy, biopsy of a metastatic lesion, or nephroureterectomy for DNA extraction.
Written informed consent provided.
None
Adult patients with muscle-invasive bladder cancer or suspected muscle-invasive upper tract urothelial carcinoma treated at AZ Sint-Lucas Gent. Participants must have available tumor tissue for DNA extraction and matched plasma samples obtained during routine clinical care.
Cohort
Prospective
Not listed
Diagnostic Performance of Plasma ctDNA for Detecting Tumor-Specific Mutations
Concordance between tumor-specific somatic mutations identified in tumor tissue and the same mutations detected in matched plasma-derived ctDNA. Diagnostic performance of the internally developed ctDNA assay will be assessed using sensitivity, specificity, positive predictive value, and negative predictive value, with tumor tissue sequencing as the reference standard.
Association Between Post-Treatment ctDNA Positivity and Disease Recurrence or Progression
Association between ctDNA positivity after surgery or radiotherapy, with or without neoadjuvant or adjuvant systemic treatment, and disease recurrence or progression during the first two years of follow-up.
Association Between Post-Treatment ctDNA Negativity and Disease Remission
Association between ctDNA negativity after surgery or radiotherapy, with or without neoadjuvant or adjuvant systemic treatment, and absence of disease recurrence or progression during the first two years of follow-up.
Association Between Preoperative ctDNA Negativity and Pathological T0 Status
Association between ctDNA negativity before surgery, with or without neoadjuvant systemic treatment, and pathological T0 status on the cystectomy specimen.
Association Between Quantitative ctDNA Decrease During Neoadjuvant Therapy and Pathological Downstaging
Association between a quantitative decrease in ctDNA levels during neoadjuvant therapy and favorable pathological response, defined as tumor downstaging at cystectomy.
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