Ménard Cynthia, Navarro-Domenech Inmaculada, Liu Zhihu Amy, Joseph Lisa, Barkati Maroie, Berlin Alejandro, Delouya Guila, Taussky Daniel, Beauchemin Marie-Claude, Nicolas Benedicte, Kadoury Samuel, Rink Alexandra, Raman Srinivas, Sundaramurthy Aravindhan, Weersink Robert, Beliveau-Nadeau Dominic, Helou Joelle, Chung Peter
Radiation Oncology, Centre Hospitaliser de l'Université de Montréal (CHUM), Montreal, QC, Canada.
Princess Margaret Cancer Centre, University of Toronto, Toronto, ON, Canada.
Front Oncol. 2022 Aug 26;12:971344. doi: 10.3389/fonc.2022.971344. eCollection 2022.
Locally recurrent prostate cancer after radiotherapy merits an effective salvage strategy that mitigates the risk of adverse events. We report outcomes of a cohort enrolled across two institutions investigating MRI-guided tumor-targeted salvage high dose rate brachytherapy (HDR-BT).
Analysis of a prospective cohort of 88 patients treated across two institutions with MRI-guided salvage HDR-BT to visible local recurrence after radiotherapy (RT). Tumor target dose ranged from 22-26 Gy, using either an integrated boost (ibBT) or focal technique (fBT), delivered in two implants over a median of 7 days. Outcome metrics included cancer control and toxicity (CTCAE). Quality of life (QoL-EPIC) was analyzed in a subset.
At a median follow-up of 35 months (6 -134), 3 and 5-year failure-free survival (FFS) outcomes were 67% and 49%, respectively. At 5 years, fBT was associated with a 17% cumulative incidence of local failure (LF) outside the GTV (vs. 7.8% ibBT, p=0.14), while LF within the GTV occurred in 13% (vs. 16% ibBT, p=0.81). Predictors of LF outside fBT volumes included pre-salvage PSA>7 ng/mL (p=0.03) and interval since RT less than 5 years (p=0.04). No attributable grade 3 events occurred, and ibBT was associated with a higher rate of grade 2 toxicity (p<0.001), and trend towards a larger reduction in QoL sexual domain score (p=0.07), compared to fBT.
A tumor-targeted HDR-BT salvage approach achieved favorable cancer control outcomes. While a fBT was associated with less toxicity, it may be best suited to a subgroup with lower PSA at later recurrence. Tumor targeted dose escalation may be warranted.
放射治疗后局部复发的前列腺癌需要一种有效的挽救策略，以降低不良事件的风险。我们报告了一项在两个机构招募的队列研究结果，该研究调查了MRI引导下肿瘤靶向挽救高剂量率近距离放射治疗（HDR-BT）。
对在两个机构接受MRI引导下挽救性HDR-BT治疗放疗（RT）后可见局部复发的88例患者的前瞻性队列进行分析。肿瘤靶区剂量范围为22-26 Gy，采用整合加量（ibBT）或聚焦技术（fBT），分两次植入，中位时间为7天。结果指标包括癌症控制和毒性（CTCAE）。对一个亚组进行了生活质量（QoL-EPIC）分析。
中位随访35个月（6-134个月）时，3年和5年无失败生存率（FFS）分别为67%和49%。5年时，fBT与GTV外局部失败（LF）的累积发生率为17%相关（ibBT为7.8%，p=0.14），而GTV内LF发生率为13%（ibBT为16%，p=0.81）。fBT体积外LF的预测因素包括挽救前PSA>7 ng/mL（p=0.03）和放疗后间隔时间少于5年（p=0.04）。未发生可归因的3级事件，与fBT相比，ibBT与2级毒性发生率较高相关（p<0.001），且在生活质量性领域评分方面有更大降低的趋势（p=0.07）。
肿瘤靶向HDR-BT挽救方法取得了良好的癌症控制效果。虽然fBT毒性较小，但可能最适合复发较晚、PSA较低的亚组。可能需要提高肿瘤靶向剂量。
