Pre-BladParadigm - the effect of diagnostic transurethral bladder tumor resection (TURBT) on the level of circulating tumor cells (CTCs) in the blood of patients suspected of muscle invasive bladder cancer

Patients who suffer from muscle invasive bladder cancer (MIBC) are commonly
treated with radical cystectomy (RC), sometimes in combination with neoadjuvant
chemotherapy (NAC). However, the 5-year survival rate for these patients
remains poor, approximately 50%, and this has not changed during the last
decades. Patients are often diagnosed with metastases within two years after
the initial surgery which suggests that micrometastases might already be
present at the time of surgery. This might be due to the preoperative procedure
used in the diagnosis of MIBC patients, namely transurethral resection of the
bladder tumor (TURBT). During TURBT the bladder is rinsed with a fluid under
high pressure while it is attempted to remove the tumor completely. This is
quite exceptional in the management of cancer. In other cancer types, the
diagnosis is only made by a biopsy plus imaging before radical treatment. The
TURBT procedure was found to be capable of damaging the bladder wall, and blood
and lymphatic vessels, which might push the tumor cells into the circulation
leading to the formation of micrometastases. Furthermore, the pressure induced
in the bladder during TURBT is higher than the venous pressure in the
surrounding blood vessels, which supports the possibility of the tumor cells
being pushed out of the bladder into the blood stream during this procedure.
These factors, together with the complexity of removing the entire tumor that
invades the bladder wall, might lead to an increased risk of developing
metastases. Previous small-scale research has suggested that the level of
circulating tumor cells (CTCs) in the blood may increase after TURBT which may
result in the formation of micrometastases and as a consequence early disease
recurrence. Furthermore, meta-analysis results showed that MIBC patients with
CTCs had a worse prognosis compared to patients with no CTCs.

To validate the suggestion that transurethral resection of bladder tumors in
patients with suspected muscle invasive bladder cancer can lead to circulating
tumor cells.

Patients who are cystoscopically suspected for muscle invasive bladder cancer
will be asked to consent with a blood draw just prior and just after the TURBT.
The blood samples are transported at room temperature within 24 hours to the
Radboudumc, processed, and tumor cells are counted with the Parsortix system.

Negligible