Efficacy and toxicity following salvage high-dose-rate brachytherapy for locally recurrent prostate cancer after radiotherapy.

INTRODUCTION:The management of local relapse after prostate cancer radiotherapy is frequently based on androgen deprivation therapy. The aim of the study was to report Gustave Roussy's experience with salvage prostate brachytherapy. PATIENTS AND METHODS:All cases of localized prostate cancer presenting in an irradiated area who received salvage high dose rate (HDR) brachytherapy from 2013 to 2020 were retrospectively reviewed. RESULTS:A total of 64 patients were included. Median follow up was 30.5 months. Median initial EBRT dose was 70 Gy [Q1-Q3: 70 - 74]. Median PSA at brachytherapy was 6.8 ng/mL [Q1-Q3: 4.4 - 8.7] with a median interval between first and salvage irradiation of 10 years [Q1-Q3: 6.9 - 12.6]. The modality of the first irradiation was an exclusive EBRT in 73% of the cases, mostly with a 3D technique (82%). Dose prescription was two fractions of 12 Gy or 13 Gy associated with androgen deprivation therapy for 63% of the patients. About 23% of the patients were castrate-resistant. Disease free survival at 2 years was 58% in the whole population and 66% in hormone sensitive patients. The only factors associated with disease free survival on multivariate analysis was a high-risk disease at initial diagnosis (HR = 3.59, IC95 [1.75; 7.39], p = 0.0005). Grade 3 urinary and rectal toxicities occurred in 1.5% and 1.5% of the patients, respectively. CONCLUSION:HDR salvage brachytherapy seems to be a safe option for patients presenting with an isolated local relapse of prostate cancer.