Department of Radiation Oncology, University of Pittsburgh, Pittsburgh, Pennsylvania.
Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario; Department of Radiation Oncology, University of Toronto, Toronto, Ontario.
Int J Radiat Oncol Biol Phys. 2022 Mar 1;112(3):735-743. doi: 10.1016/j.ijrobp.2021.10.003. Epub 2021 Oct 9.
Guidelines from the American Society of Clinical Oncology and Cancer Care Ontario recommend brachytherapy boost for patients with intermediate-risk or high-risk prostate cancer. SABR is an emerging technique for prostate cancer, but its use in high-risk disease is limited. Efficacy, toxic effects, and quality of life (QoL) were compared in patients treated on 2 prospective protocols that used SABR boost or magnetic resonance-guided high-dose-rate brachytherapy (HDR-BT) boost with 6 to 18 months of androgen deprivation therapy (ADT).
In SATURN study (study 1), patients received 40 Gy to the prostate and 25 Gy to the pelvis in 5 weekly fractions. In SPARE (study 2), patients received HDR-BT (15 Gy × 1) to the prostate and ≤22.5 Gy to the magnetic resonance imaging nodule, followed by 25 Gy in 5 weekly fractions to the pelvis. All patients received between 6 and 18 months of ADT.
Thirty patients (7% unfavorable intermediate risk and 93% high risk, per National Comprehensive Cancer Network [NCCN] criteria) completed study 1, and 31 patients (3% favorable intermediate risk, 47% unfavorable intermediate risk, and 50% high risk) completed treatment as per study 2. The median follow-up times were 72 and 62 months, respectively. In study 2, 6 patients had biochemical failure, and all 6 developed metastatic disease. Actuarial 5-year biochemical failure was 0% for study 1 and 18.2% for study 2 (P = .005). There was no significant difference in the worst acute or late gastrointestinal or genitourinary toxicity. Grade 3 late genitourinary toxicity was noted in 3% of the patients in study 2 (HDR-BT boost). There was either no significant difference or minimal clinically important change in QoL.
In the context of 5-fraction pelvic radiation therapy and ADT, there did not appear to be a significant difference in toxicity or QoL between SABR and HDR-BT boost. Although efficacy favored the SABR boost cohort, this should be viewed in the context of limitations and biases associated with comparing 2 sequential phase 2 studies.
美国临床肿瘤学会和安大略省癌症护理协会的指南建议对中危或高危前列腺癌患者进行近距离放疗加量。SABR 是一种新兴的前列腺癌治疗技术，但在高危疾病中的应用受到限制。本研究比较了接受 SABR 加量或磁共振引导高剂量率近距离放疗（HDR-BT）加量并接受 6 至 18 个月雄激素剥夺治疗（ADT）的前瞻性研究方案 1（研究 1）和方案 2（SPARE）的患者的疗效、毒性作用和生活质量（QoL）。
在 SATURN 研究（研究 1）中，患者接受 5 周内每周 5 次共 40 Gy 的前列腺剂量和 25 Gy 的盆腔剂量。在 SPARE 研究（研究 2）中，患者接受 HDR-BT（15 Gy×1）对前列腺进行治疗，对磁共振成像结节给予≤22.5 Gy 的剂量，然后对盆腔进行 5 周内每周 5 次共 25 Gy 的治疗。所有患者均接受 6 至 18 个月的 ADT。
30 例患者（根据国家综合癌症网络[NCCN]标准，7%为不利的中危，93%为高危）完成了研究 1，31 例患者（3%为有利的中危，47%为不利的中危，50%为高危）按研究 2 完成了治疗。中位随访时间分别为 72 个月和 62 个月。在研究 2 中，有 6 例患者出现生化失败，所有 6 例均发生了转移性疾病。研究 1 的 5 年生化失败率为 0%，研究 2 为 18.2%（P=0.005）。急性或晚期胃肠道或泌尿生殖系统毒性的严重程度无显著差异。研究 2 中 3%的患者出现 3 级晚期泌尿生殖系统毒性（HDR-BT 加量）。QoL 方面没有显著差异或仅有最小的临床意义的变化。
在 5 次盆腔放疗和 ADT 的背景下，SABR 和 HDR-BT 加量之间在毒性或 QoL 方面似乎没有显著差异。尽管 SABR 加量组的疗效较好，但这应结合比较两项序贯 2 期研究的局限性和偏倚来考虑。
