The aim of this explorative study is to evaluate whether EpiCheck can be used as a predictor of tumour response to short-term, intensive chemoresection with Mitomycin.

The study will be conducted as an exploratory, prospective observational study. Participants consists of patients referred to short-term, intensive chemoresection due to recurrent NMIBC. The treatment adhere to the regimen described in the NICSA trial with the ClinicalTrials.gov identifier NCT03348969. Treatment consists of short-term, intensive chemoresection with Mitomycin; 40 mg is administered intravesically three times a week for two weeks. To evaluate tumour response, an early cystoscopy is performed in the outpatient clinic one to two months after treatment completion. No visible tumour and residual tumour with benign histology is considered complete response. Residual tumour tissue with neoplastic histology is considered incomplete response and will be treated with TURBT or tumour fulguration. Subsequently patients continue a standardized follow-up program as Danish guidelines prescribe which is initiated after four months.

Inclusion Criteria:

• Patients with a known history of Ta HG with recurrent disease
• Patients referred to short-term, intensive chemoresection
• Patients older than 18 years

Exclusion Criteria:

• Known allergy or intolerance to Mitomycin
• Incontinence or small bladder capacity (< 100 mL)
• Previous pelvic radiation therapy

Patients with a known history of Ta HG with recurrent disease and who are referred to short-term, intensive chemoresection