Radiation instead of bladder removal: a new option for Hard-to-Treat bladder cancer?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Histologically confirmed, BCG-unresponsive, high-risk non-muscle-invasive bladder cancer (according to EAU guidelines \[2\] (see table 1)) °of predominantly (\>50%) urothelial histology who were ineligible for or declined to undergo radical cystectomy. * Patients with carcinoma in situ with or without high-grade Ta or T1 are allowed if patients with concomitant Ta and T1 tumors have undergone complete TURBT, defined as per standard of care as a visually complete resection. A second TURBT is recommended but not required for patients with T1 tumor. * The most recent cystoscopy or TURBT must have been done within 12 weeks before study enrolment. * Eastern Cooperative Oncology Group performance status of 0-2 * Adequate organ function (at minimum WBC \> 4.0 × 109/L; platelets \> 100 × 109/L; GFR \> 25mL/min) * 18 years or older * Women of childbearing potential (WOCBP) must have a negative serum pregnancy test within 72 hrs prior to the first day of radiation. * Patients of childbearing / reproductive potential should use adequate birth control measures during the study treatment period and for at least 4 weeks after the last day of radiation. A highly effective method of birth control is defined as a method which results in a low failure rate (i.e., less than 1% per year) when used consistently and correctly. Such methods include: * Combined (oestrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation (oral, intravaginal, transdermal) * Progestogen-only hormonal contraception associated with inhibition of ovulation (oral, injectable, implantable) * Intrauterine device (IUD) * Intrauterine hormone-releasing system (IUS) * Bilateral tubal occlusion * Vasectomized partner * Sexual abstinence (the reliability of sexual abstinence needs to be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the patient) * Before patient 's enrolment, written informed consent must be given according to ICH/GCP, and national/local regulations. Exclusion Criteria: * Evidence of muscle invasive or metastatic urothelial carcinoma * Evidence of upper urinary tract carcinoma * Poor bladder function (IPSS \>16) * Hydronephrosis due to tumour in the presence of T1 disease * Patients on current systemic therapy for bladder cancer * Patients who have received pelvic external beam radiotherapy within the previous 5 years * Any known contraindications or allergies to the use of local standard of care radiosensitiser, if applicable