Background: Non-muscle invasive bladder cancer (NMIBC) is associated with a high yearly recurrence rate up to to 61%. Patients affected are therefore referred to long-term or even life-long follow-up, which burdens both patients and health care system. Recurrent tumours are most frequently treated with TURBT followed by adjuvant intravesical treatment. Repeat TURBT includes a risk of morbidity from the procedure itself and from general anaesthetics, which the procedure requires. Patients with NMIBC are generally elderly, multi-morbid, and as a result, they often show a poor tolerability of general anaesthetics. Thus, the need for non-surgical treatment modalities is imminent and continuous investigations are performed in the field including active surveillance, chemoresection and device-assisted intravesical chemotherapy. Laser ablation is a technique gaining attention in the treatment of NMIBC, based on the prospects of an outpatient treatment modality, which could prove TURBT and general anaesthesia unnecessary in select patients.

Methods: The study will be conducted as a prospective feasibility study. Included patients will undergo outpatient laser ablation using the Olympus Soltive laser under local anaesthetics. Patients will be included from Aarhus University Hospital (Denmark), Fundació Puigvert (Spain), Motol University Hospital (Czech Republic) and Institut Universitaire du Cancer Toulouse Oncopole (France). Data will be reported to the eCRF in the online REDCap web application. The eCRF is stored on a secure server under the responsibility of the Department of Clinical medicine at Aarhus University in Denmark. REDCap is a secure web application for building and managing online surveys and databases. The Database will be in agreement with the laws and regulations of the Danish Data Protection Agency and EU regulations (GDPR). The sponsor will be overall responsible for the data entry in the eCRF, and the validity of the data collected at the specific sites. Each participant will be coded with a unique patient identifier to ensure pseudo anonymity. Perspectives: This study will be the first multinational study with focus on feasibility of outpatient laser ablation of large bladder tumours between 1-3 cm. Outpatient laser ablation of these large tumours has the potential to reduce the number of TURBTs per patient, thus easing the life of patients with non-muscle invasive bladder cancer, with fewer surgical procedures as well as reducing the overall treatment related costs for society. If thulium laser ablation proves effective, the treatment modality would be easily implemented and available based on the small size of the machinery.