A Randomized Comparison of High Dose Rate and Low Dose Rate Prostate Brachytherapy Combined with External Beam Radiotherapy for Unfavourable Prostate Cancer: Efficacy Results after Median Follow-up 74 Months
Mené sur 195 patients atteints d'un cancer de la prostate localisé et de pronostic défavorable (âge médian : 71 ans ; durée médiane de suivi : 74 mois), cet essai randomisé évalue l'efficacité, du point de vue de la qualité de vie, d'un traitement combinant une radiothérapie externe pelvienne et une curiethérapie prostatique en fonction du débit de dose (fort ou faible)
Purpose: This single center randomized trial compared health-related QOL for men with unfavorable localized prostate cancer treated with combined pelvic external beam radiation (EBRT) and prostate brachytherapy (BT), randomly assigned to High Dose Rate (HDR) or Low Dose Rate (LDR). We now report efficacy outcomes with minimum 5 year follow up.
Materials and Methods: Consenting patients receiving pelvic EBRT combined with prostate BT were randomized to either LDR (110Gy) or HDR (15Gy). Androgen deprivation was used in 76%. EBRT delivered 46 Gy/23 using IMRT or VMAT (68%) or 3DcRT (32%). Followup up was 1-, 3-, and 6-mo, then every 6 mo to 3 years, then annually. PSA ≤ 0.2ng/ml at 4 years defined cure. Biochemical failure-free survival (bFFS), and overall survival (OS) were calculated by Kaplan Meier methods. All failures were investigated by imaging (CT, bone scan and/or PSMA PET) ± biopsy if PET not available.
Results: From 01/2014 to 12/2019, 195 men (42% IR/ 58% HR) were randomly assigned: 108 to HDR and 87 to LDR. Median age was 71 years. Median PSA was 11.6 ng/ml (mean 27.0 ng/ml). Median follow up was 74 months (43m – 116m). Median PSA nadirs were 0.07 and 0.08 in HDR and LDR (p=0.16), and time to nadir was 13.8 and 14.1 mo respectively (p=0.87). 4-year PSA ≤ 0.2 was maintained in 81% and 83% of HDR and LDR (p=0.91). 8-year bFFS (nadir+2) was 86% and 85% respectively. 18 of 22 BF have been identified: 3 are isolated LF while 14 are distant (isolated 11; 3 combined).
Conclusions: In this small, randomized comparison, efficacy analysis shows no difference between LDR and HDR boost in biochemical FFS at 5 and 8 years and confirms the excellent efficacy of dose escalation using prostate brachytherapy as documented in Ascende-RT for unfavorable localized prostate cancer.
International Journal of Radiation Oncology, Biology, Physics , résumé, 2025