Fuller Donald B, Crabtree Tami, Kane Brent L, Medbery Clinton A, Pfeffer Robert, Gray James R, Peddada Anuj, Royce Trevor J, Chen Ronald C
CyberKnife Centers of San Diego, San Diego, CA, United States.
Advance Research Associates, Santa Clara, CA, United States.
Front Oncol. 2022 Jul 29;12:935310. doi: 10.3389/fonc.2022.935310. eCollection 2022.
PURPOSE/OBJECTIVES: Although ample intermediate-term prostate stereotactic body radiotherapy (SBRT) outcomes have been reported, 10-year results remain relatively sparse.
MATERIALS/METHODS: Eighteen institutions enrolled 259 low- and intermediate-risk patients. Median follow-up is 5.5 years, with 66 patients followed ≥ 10 years. This SBRT regimen specifically emulated an existing HDR brachytherapy dose schedule and isodose morphology, prescribed to 38 Gy/4 fractions, delivered daily by robotic SBRT, mandating > 150% dose escalation in the peripheral zone. Androgen deprivation therapy was not allowed, and a hydrogel spacer was not available at that time.
Median pre-SBRT PSA 5.12 ng/mL decreased to 0.1 ng/mL by 3.5 years, with further decrease to a nadir of < 0.1 ng/mL by 7 years, maintained through 10 years. Ten-year freedom from biochemical recurrence measured 100% for low-risk, 84.3% for favorable intermediate risk (FIR), and 68.4% for unfavorable intermediate (UIR) cases. Multivariable analysis revealed that the UIR group bifurcated into two distinct prognostic subgroups. Those so classified by having Gleason score 4 + 3 and/or clinical stage T2 (versus T1b/T1c) had a significantly poorer 10 year freedom from biochemical recurrence rate, 54.8% if either or both factors were present, while UIR patients without these specific factors had a 94.4% 10-year freedom from biochemical recurrence rate. The cumulative incidence of grade 2 GU toxicity modestly increased over time - 16.3% at 5 years increased to 19.2% at 10 years-- while the incidence of grade 3+ GU and GI toxicity remained low and stable to 10 years - 2.6% and 0%, respectively. The grade 2 GI toxicity incidence also remained low and stable to 10 years - 4.1% with no further events after year 5.
This HDR-like SBRT regimen prescribing 38 Gy/4 fractions but delivering much higher intraprostatic doses on a daily basis is safe and effective. This treatment achieves a median PSA nadir of <0.1 ng/mL and provides high long-term disease control rates without ADT except for a subgroup of unfavorable intermediate-risk patients.
目的/目标：尽管已有大量关于前列腺立体定向体部放疗（SBRT）的中期结果报道，但10年的结果仍然相对较少。
材料/方法：18家机构纳入了259例低危和中危患者。中位随访时间为5.5年，其中66例患者随访时间≥10年。该SBRT方案特别模仿了现有的高剂量率近距离放疗剂量计划和等剂量形态，处方剂量为38 Gy分4次，由机器人SBRT每日进行，要求外周区剂量增加>150%。不允许进行雄激素剥夺治疗，且当时没有水凝胶间隔物。
SBRT前中位前列腺特异性抗原（PSA）为5.12 ng/mL，到3.5年时降至0.1 ng/mL，到7年时进一步降至最低点<0.1 ng/mL，并维持至10年。低危患者10年无生化复发率为100%，有利中危（FIR）患者为84.3%，不利中危（UIR）患者为68.4%。多变量分析显示，UIR组分为两个不同的预后亚组。那些因Gleason评分4+3和/或临床分期T2（相对于T1b/T1c）而被分类的患者，其10年无生化复发率明显较差，如果存在其中一个或两个因素，复发率为54.8%，而没有这些特定因素的UIR患者10年无生化复发率为94.4%。2级泌尿生殖系统毒性的累积发生率随时间略有增加——5年时为16.3%，10年时增至19.2%——而3级及以上泌尿生殖系统和胃肠道毒性的发生率在10年时保持较低且稳定，分别为2.6%和0%。2级胃肠道毒性发生率在10年时也保持较低且稳定——为4.1%，5年后无进一步事件发生。
这种类似高剂量率近距离放疗的SBRT方案，处方剂量为38 Gy分4次，但每天给予更高的前列腺内剂量，是安全有效的。这种治疗使PSA中位最低点<0.1 ng/mL，并提供了高长期疾病控制率，除了一小部分不利中危患者外无需雄激素剥夺治疗。
