ultra hypofractionnated radiotherapy with hdr brachytherapy boost.

Conditions: Prostate Cancer; Radiotherapy Side Effect; Hypofractionation; Brachytherapy; Radiotherapy; Localized Prostate Carcinoma

Summary: phase 1-2 study, comparing ultra-hypofractionnated (uh) to a moderately hypofractionnated (mh) radiation therapy, with image guided hdr prostate brachytherapy. using iso-equivalent doses, a non-inferiority analysis will be done in order to prove uh non-inferior to mh, toxicity wise. acceptability, tolerability, acute and late toxicity will be reported. mri visible dominant intra-prostatic lesion will be outlines and variability between radiation oncologists and radiologists will be reported. as secondary objective, biochemical and clinical failure free survival will be reported at 5 \& 10 years.

phase 1 : consists in a feasibility study (first 28 patients). phase 2 : monocentric prospective comparative cohort study. recruitment : * "centre intégré de cancérologie du chu de québec-université laval." * recruitment period: december 2015 to june 2023 brachytherapy : * implantation under general or spinal anesthesia * foley catheter insertion in bladder. * trus prostate localisation. * prostate volume measurement. * gold fiducial markers (3) insertion. * prostate brachytherapy catheters (14 à 21) insertion. * cystoscopy for bladder and urethra integrity control. * re-insertion of foley catheter after cystoscopy. planning imaging: trus or ct scan (has needed). structures delineation by radiation oncologist (brachytherapist). * prostate * seminale vesicles * rectum * colon sigmoïde * bladder * urethra * penile bulb dosimetric optimisation * oncentra prostate v. 4.2.2 d'elekta brachytherapy (veenendaal, the netherlands) * oncentra brachy version 4.6 (if under ct scan). treatment (brachytherapy dose delivery). * 15 gy in one fraction * direct interstitial dose monitoring (20 patients or more). fiber-optic dosimeter inserted in prostate brachytherpy catheter for live dose delivery mesurements. foley ablation under full bladder, same day or day after therapy. radiotherapy: * via imrt, vmat or sbrt technics. * dose : 25 gy in 5 fractions administered over a 7 days period. 2 to 3 fractions separated by 2 days, weekend break. * ptv includes prostate and the first centimeter of seminal vesicle. simulation * one week post brachytherapy * standard has described in the department procedure manual. * maximal ct scan slice thickness : 2-3mm. * uretro-graphy done to identify urogenital sphincter. multiparametric mri * if no counter-indication and available, * a t2 tridimensional sequence for prostate delineation * slice thickness : 1 mm. * a diffusion weighted sequence will be done. * a dti with tractography can be done optionally. * contrast media (gadolinium) is optional. physique * linac energy (between 6 mv to 18 mv). * arc therapy technique will be used * planification softwares: éclipse, pinnacle or raystation. * portal (kv-kv) imagery will be used for marker match. * cbct will be done at each fraction delivered. clinical and dosimetric data will be collected prior treatment. primary objectives : * toxicity analysis will be quantitatively evaluated using ctcae (v5) at 1, 2 and 5 years post-therapy, and has needed at fu visits. kaplan-meier statistical analysis will be used to report toxicity evolution through time. * median ipss scores will be reported at 3, 6, 12 months and yearly (1, 2, 3, 4 et 5) post-therapy. ipss median time to baseline return will be calculated. * ipss urinary scores, sexual function (shim) and gi toxicity (ctcae-v5) and quality of life questionnaires ( epic-26) will be given at 3, 6 months and yearly thereafter (1, 2, 3, 4 et 5) post-treatment. secondary objectives : biochemical disease-free survival has per phoenix definition (by american society of radiation oncology - astro) recommendation will be reported using kaplan-meier analysis.

Eligibility criteria:
inclusion criteria: * biopsy proven prostate adenocarcinoma * stage t1c, t2 (annex 2) * stage nx or n0 * stage mx or m0 * psa \< 20ng/ml * gleason score 6 or 7 * having the ability to sing a written consent exclusion criteria: * age \< 18ans * clinical stage t3 or t4 * stage n1 * stage m1 * psa \> 20 * gleason score 8 to 10 * ipss score \> 20 alpha-blocking medication. * prior pelvic radiotherapy. * history of active collagenosis (lupus, sclerodermia, dermatomyosis) * past history of inflammatory bowell disease * bilateral hip prosthesis

Keywords: hypo fractionation brachytherapy ultra hypo fractionation