New radiation technique aims to cut bowel problems in bladder cancer treatment

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

Inclusion Criteria: * Histologically proven muscle-infiltrating bladder cancer (de novo MIBC or after a history of non-muscle-invasive bladder cancer) or patients with initial high-grade T1 tumor showing Ta or T1 recurrence, or those with high-grade T1 after a course of intravesical biological therapy or chemotherapy; * Age ≥ 18 years; * Urothelial carcinoma (transitional cell carcinoma of the bladder, micropapillary, microcystic with trophoblastic differenciation) and squamous cell histological types are allowed; * Stage T1-T4aN0M0 * TransUrethral Resection of Bladder Tumor (TURBT) and Position Emission Tomography- scanner and X-ray Computed Tomography (PET-CT) or Computed Tomography scan of thorax/abdomen/pelvis (without carcinological anomaly) within 8 weeks prior to the start of radiation therapy (if TURBT was performed more than 6 weeks before the inclusion visit, a new TURBT or, at least, a cystoscopy showing no progression, no residual tumour or regrowth must be done); * Suitable for radiotherapy; * Eastern Cooperative Oncology Group/World Human Organisation (ECOG/WHO) performance status from 0 to 2 * Negative pregnancy test (blood or urine), for women of childbearing age only; * If the patient is sexually active, he/she must agree to use contraception deemed adequate and appropriate by the investigator throughout the period of study drug administration and 6 months after the end of treatment for both men and women. * Affiliation to the French Social Security System; * Dated, written and signed Informed consent Exclusion Criteria: * Prior pelvic radiation therapy; * Patients with previous or concomitant other malignancy within the past 5 years EXCEPT adequately treated basal or squamous cell carcinoma of the skin or in situ carcinoma of the cervix. Patients who have had a previous other malignancy must have been disease free for at least five years; * Presence of endopenic stent; * Inability to comply with the protocol; * Grade 1 or greater baseline diarrhea; * Uncontrolled inflammatory bowel disease (ulcerative colitis or Crohn's disease); * Uncontrolled immune or cardiac or pulmonary disease; * Patients whose regular follow-up is impossible for psychological, family, social or geographical reasons; * Legal incapacity or physical, psychological or mental status interfering with the patient's ability to sign the informed consent or to terminate the study; * Pregnant or breast-feeding subjects