Goddard Lee C, Cabrera Jonathan, Tang Justin, Garg Madhur K, Tome Wolfgang A
Radiation Oncology, Montefiore Medical Center, Bronx, USA.
Institute for Onco-Physics, Albert Einstein College of Medicine, Bronx, USA.
Cureus. 2025 Apr 13;17(4):e82197. doi: 10.7759/cureus.82197. eCollection 2025 Apr.
Stereotactic body radiation therapy (SBRT) is a well-established treatment for localized prostate cancer, offering excellent tumor control with reduced treatment fractions. However, prostate motion due to physiological processes poses a challenge to precise dose delivery. This study evaluates the dosimetric outcomes, prostate-specific antigen (PSA) response, and toxicity profile of prostate SBRT using real-time adaptive motion management with the Radixact Synchrony system (Accuray Inc., Madison, WI).
A retrospective analysis was conducted on 25 prostate cancer patients treated with SBRT (40 Gy in 5 fractions) using the Radixact Synchrony system between January 2021 and December 2023. All patients underwent CT simulation with fiducial markers, and 24/25 patients had MRI fusion for target and organ-at-risk (OAR) delineation. Treatment plans were generated using either the "Classic" or "VOLO Ultra" algorithms. Intrafraction prostate motion was analyzed, and toxicity was assessed using the Common Terminology Criteria for Adverse Events (CTCAE) v4.03 scale at regular follow-up intervals.
The median clinical target volume (CTV) for the prostate was 46.8 cm³ (range, 22.6-107.3 cm³), and the median pre-treatment PSA was 6.52 ng/mL. All plans achieved favorable target coverage while adhering to OAR dose constraints. The median post-treatment PSA value was 0.30 ng/mL with a median follow-up time of 28 months, with all patients achieving PSA levels below 2.0 ng/mL at 15 months. Motion >2 mm was observed in at least one treatment fraction for all but one patient. Real-time adaptive motion management successfully corrected for prostate displacement, with an average imaging interval of 8.4 seconds. A total of 14 patients reported new grade 1 genitourinary (GU) symptoms, and three patients experienced grade 2 GU toxicity post-treatment.
Prostate SBRT with real-time adaptive motion management using the Radixact Synchrony system achieves excellent target coverage while mitigating the effects of intrafraction motion. The observed PSA response supports its efficacy, and OAR dose metrics remain within acceptable limits. While real-time motion adaptation was beneficial for nearly all patients, further studies with larger cohorts and patient-reported outcomes are warranted to assess long-term toxicity and quality of life.
立体定向体部放射治疗（SBRT）是一种成熟的局限性前列腺癌治疗方法，能在减少治疗分次的情况下实现出色的肿瘤控制。然而，生理过程导致的前列腺运动对精确剂量输送构成挑战。本研究使用Radixact Synchrony系统（Accuray公司，威斯康星州麦迪逊）的实时自适应运动管理评估前列腺SBRT的剂量学结果、前列腺特异性抗原（PSA）反应和毒性情况。
对2021年1月至2023年12月期间使用Radixact Synchrony系统接受SBRT治疗（5次分割，每次40 Gy）的25例前列腺癌患者进行回顾性分析。所有患者均接受了带有基准标记的CT模拟，25例患者中有24例进行了MRI融合以勾画靶区和危及器官（OAR）。使用“经典”或“VOLO Ultra”算法生成治疗计划。分析了分次内前列腺运动情况，并在定期随访时使用不良事件通用术语标准（CTCAE）v4.03量表评估毒性。
前列腺的中位临床靶体积（CTV）为46.8 cm³（范围22.6 - 107.3 cm³），治疗前PSA的中位值为6.52 ng/mL。所有计划在遵守OAR剂量限制的同时实现了良好的靶区覆盖。治疗后PSA的中位值为0.30 ng/mL，中位随访时间为28个月，所有患者在15个月时PSA水平均低于2.0 ng/mL。除1例患者外，所有患者在至少一个治疗分次中观察到运动>2 mm。实时自适应运动管理成功校正了前列腺位移，平均成像间隔为每8.4秒一次。共有14例患者报告出现新的1级泌尿生殖系统（GU）症状，3例患者治疗后出现2级GU毒性。
使用Radixact Synchrony系统进行实时自适应运动管理的前列腺SBRT在减轻分次内运动影响的同时实现了出色的靶区覆盖。观察到的PSA反应支持其疗效，OAR剂量指标仍在可接受范围内。虽然实时运动适应对几乎所有患者都有益，但需要进一步开展更大样本队列研究和患者报告结局评估，以评估长期毒性和生活质量。
