Solifenacin Succinate for Treatment of Urinary Toxicity Occurring During Radiotherapy of Prostatic Cancer

Inclusion Criteria:

* Prostate adenocarcinoma (histological confirmation),
* Indication for prostate cancer radiotherapy (standard schema with a total dose from 70 to 80 Gray (GY)),
* Patient affiliation to the French Social Security System,
* Patient information and written informed consent,
* Patient complaining of urinary symptoms during radiotherapy,
* Occurrence of OverActive Bladder (OAB) subscore with the Urinary Symptom Profile (USP) scale greater or equal to 5.

Exclusion Criteria:

* Prostate irradiation contraindication
* History of bladder or prostate surgery,
* History of of pelvic radiotherapy,
* Individual deprived of liberty or placed Under the authority of a tutor,
* Age \< 18 years,
* Flowmetry Qmax \< 10ml/s and/or post-void residual urine \> 100 ml (during urology preinclusion visit)
* Previous known OAB
* Patients treated with non-authorized drugs,
* Patients treated with anticholinergic or cholinesterase inhibitors within 12 months before irradiation,
* Patients treated with anticholinergic during and weeks following irradiation and before Succinate of Solifenacin treatment start,
* Patients treated with botulinum toxin within 9 months before screening,
* Patients treated with alpha-blockers, 5-alpha reductase inhibitor within 12 months preceding irradiation, during and weeks following irradiation and before Succinate of Solifenacin treatment start,
* Contraindication of Succinate of Solifenacin
* Hypersensitivity or allergy to Solifenacin succinate or to any other antimuscarinic agent,
* Specific precautions of use for patients having decompensated urinary tract obstruction at risk of urinary retention, vegetative neuropathy, long QT syndrome and an hypokaliemia, history of long QT or patients at risk of QT prolongation, obstructive gastrointestinal disorders.
* Patients treated with oral biphosphonates, drugs that cause QT prolongation or by substrates having affinity for CYP3A4 isoenzyme as verapamil and Diltiazem, or treated with CYP3A4 inductors as rifampicin, phenytoin, carbamazepine
* Galactose hereditary intolerance, lactase deficiency or a malabsorption syndrome of glucose and galactose.
* Patient enable to follow study medical care for family, social, geographical or psychological reasons.
* Participation to another clinical study on urinary toxicity and/or molecule that could modify this toxicity and its evolution.