PSMA PET/MR導引之攝護腺切除術後救援治療：放射治療與放射治療合併雄激素剝奪治療之比較

黃昱凱¹, 魏子鈞^1,5, 黃志賢^1,5, 張延驊^1,5, 鍾孝仁^1,5, 林志杰^1,5, 黃子豪^1,5 ,

陳威任^1,5, 劉裕明², 康鈺玫², 沈書慧³, 林可瀚⁴, 王昱豐⁴, 黃逸修^1,5

¹泌尿部, ²重粒子及放射腫瘤部, ³影像診療部, ⁴核醫部

臺北榮民總醫院

⁵書田泌尿科學研究中心 國立陽明交通大學醫學院泌尿學科

Tailoring Salvage Therapy After Prostatectomy: PSMA PET/MR–Guided Comparison of Radiotherapy Alone Versus Radiotherapy Plus ADT

Yu-Kai Huang¹, Tzu-Chun Wei^1,5, William J. Huang^1,5, Yen-Hwa Chang^1,5,

Hsiao-Jen Chung^1,5, Chih-Chieh Lin^1,5, Tzu-Hao Huang^1,5 , Wei-Jen Chen^1,5, Yu-Ming Liu², Yu-Mei Kang², Shu-Huei Shen³, Ko-Han Lin⁴, Yuh-Feng Wang⁴,

Eric Yi-Hsiu Huang^1,5

¹Department of Urology, ²Department of Heavy Particles & Radiation Oncology, ³Department of Radiology, ⁴Department of Nuclear Medicine

Taipei Veterans General Hospital

⁵Department of Urology, School of Medicine and Shu-Tien Urological Science Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan

Purpose: PSMA PET has emerged as a powerful diagnostic tool for detecting biochemical recurrence (BCR) in prostate cancer. F-18-PSMA-1007 PET/MR (PSMA PET/MR) offers improved pelvic imaging due to its low urinary excretion, enabling more accurate identification of local recurrence. In patients with low-risk BCR, salvage radiotherapy (RT) represents a potentially curative approach. However, the optimal role of concurrent androgen deprivation therapy (ADT) in this subgroup remains uncertain. This study aimed to evaluate the clinical outcomes of salvage RT alone versus RT combined with ADT in patients with PSMA PET/MR–defined local recurrence only.

Materials and Methods: We retrospectively reviewed 108 prostate cancer patients with BCR or persistent PSA following prostatectomy (2021–2023) who had undergone PSMA PET/MR. BCR risk stratification followed EAU and AUA criteria, and recurrence was categorized as local-only or other. Thirty-eight patients (35.2%) demonstrated isolated local recurrence; 12 received RT alone (RT group) and 26 received RT plus concurrent ADT (RT+ADT group). Clinical characteristics, PSA kinetics, and biochemical progression-free survival (bPFS) were compared between groups. bPFS was defined as the presence of new lesions or PSA increase ≥ nadir + 0.2 ng/mL. PSA response at 3 and 6 months, PSA decline percentage, and time to PSA nadir were analyzed using Chi-squared and Mann-Whitney U tests.

Results: Isolated local recurrence was significantly more frequent in low-risk BCR patients defined by EAU criteria (72.7% vs. 27.3%, p<0.05). Among these, mean age was 70.8±5.3 years in the RT group and 68.9±6.4 years in the RT+ADT group, with mean follow-up of 49.5±20.0 and 52.4±20.1 months, respectively. No deaths occurred. Biochemical progression was observed in only one patient (RT+ADT group). Three-year bPFS were 100% in RT group and 95.7% in RT+ADT group. Compared with RT alone, RT+ADT achieved greater PSA decline at 3 months (66.5% vs. 90.6%, p<0.001) and 6 months (84.6% vs. 97.9%, p<0.001), and a shorter time to PSA nadir (11.7 vs. 4.6 months, p<0.001). Nadir PSA values did not significantly differ between groups (0.03 vs. 0.01 ng/mL, p=0.093).

Conclusions: F-18-PSMA-1007 PET/MR effectively identified a high proportion of isolated local recurrence, particularly among low-risk BCR patients by EAU criteria. Concurrent ADT with RT accelerated PSA decline and time to nadir compared with RT alone, but no difference was observed in nadir PSA and short-term bPFS. These findings suggest that RT alone may remain an appropriate option in selected patients to avoid ADT-related morbidity, while RT+ADT may enhance short-term biochemical response. Prospective studies are warranted to define optimal integration of ADT in PSMA PET–guided salvage strategies.