Impact of diagnostic transurethral bladder tumour resection on the release of circulating tumour cells

Objective To evaluate the impact of transurethral resection of the bladder tumour (TURBT) on the release of circulating tumour cells (CTCs) in patients suspected of having muscle-invasive bladder cancer (MIBC) and to assess metastasis in follow-up analysis. Materials and methods In this prospective pilot study for the BladParadigm trial, patients suspected of having MIBC were recruited and underwent TURBT for local staging. Peripheral blood samples were collected just before and immediately after TURBT. CTCs were enriched using the Parsortix® PR1 microfluidics system. Cytokeratin-positive CTCs were counted using fluorescence microscopy. Progression and survival were evaluated at 2 years since inclusion. Results Of 18 patients included, seven were diagnosed with NMIBC and eleven with MIBC. Of all MIBC patients, 1 patient was already CTC-positive before TURBT. Four other MIBC patients were CTC-positive only after TURBT, indicating a CTC rise after TURBT in 40% (4/10) of pre-TURBT CTC-negative MIBC cases. Two out of these four patients experienced progression within two years, of whom one deceased. Two out of six CTC-negative patients before and after TURBT also experienced progression. Conclusion We demonstrate the feasibility of using label-free enrichment to capture and enumerate bladder cancer-derived CTCs. Our findings indicate that TURBT might lead to the spread of CTCs. Although this feasibility study lacks power, the detection of TURBT-associated CTCs suggests a need to study non-invasive alternatives for local staging of bladder cancer.