PURPOSE/OBJECTIVES There are no published reports of prostate specific membrane antigen (PSMA) positron emission tomography (PET) guided dose-escalated intensity-modulated radiation therapy (DE-IMRT) in newly diagnosed lymph node (LN) positive prostate cancer. We report early toxicity and efficacy outcomes with this approach. MATERIALS/METHODS Patients with newly diagnosed high-risk prostate cancer were staged using PSMA PET, computed tomography (CT) and bone scans. Patients with LN positive-only metastases were offered curative therapy using 3 months androgen deprivation therapy (ADT) followed by DE-IMRT (using volumetric arc therapy), and 3 years adjuvant ADT. All patients had fiducial marker insertion, with privately insured patients having spacer hydrogel insertion. PET and prostate magnetic resonance imaging were fused with the planning CT. We aimed to deliver 81 Gy in 45 fractions (Fx) to the prostate and PET-positive LNs, and 60 Gy in 45Fx to bilateral elective pelvic LNs. RESULTS In all, 46 patients were treated, with 83% Gleason 8-10, 67% T3/T4, median number of LNs 2 (range 1-6), and median PET-positive LN volume 1.14 cc (range 0.15-4.14). LNs were outside of standard contouring guidelines in 37% of patients. The mean PET-positive LN clinical target volume dose ranged from 73.3 to 85.9 Gy (median 83.6 Gy). With 24 months median follow-up, two year failure-free survival was 100%, and 2 year overall survival 95.7%. Acute grade 1 and 2 GI toxicity occurred in 48 and 11% of patients, and GU toxicity in 72 and 24%. Late grade 1, 2 and 3 GI toxicity occurred in 13, 2 and 0%, and GU toxicity 28, 13 and 4%. No toxicity was attributable to the high dose LN boost. CONCLUSIONS PSMA PET-guided DE-IMRT up to 81 Gy to the prostate and involved LNs, and long term ADT, is a promising approach for newly diagnosed LN positive prostate cancer. LN contouring guidelines require re-evaluation in the era of PSMA PET imaging.

中文翻译：

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PSMA-PET 引导的剂量递增容积弧治疗 (VMAT) 用于新诊断的淋巴结阳性前列腺癌：两年的疗效和毒性结果

目的/目的 没有关于前列腺特异性膜抗原 (PSMA) 正电子发射断层扫描 (PET) 引导剂量递增调强放射治疗 (DE-IMRT) 治疗新诊断淋巴结 (LN) 阳性前列腺癌的已发表报告。我们报告了这种方法的早期毒性和疗效结果。材料/方法 使用 PSMA PET、计算机断层扫描 (CT) 和骨扫描对新诊断的高危前列腺癌患者进行分期。仅 LN 阳性转移的患者接受了 3 个月雄激素剥夺疗法 (ADT) 和 DE-IMRT（使用容积弧疗法）和 3 年辅助 ADT 的治愈性治疗。所有患者都有基准标记插入，私人保险患者插入间隔水凝胶。PET 和前列腺磁共振成像与计划 CT 融合。我们的目标是将 81 Gy 分 45 次 (Fx) 输送到前列腺和 PET 阳性 LN，并将 45Fx 中的 60 Gy 输送到双侧选择性盆腔 LN。结果 总共有 46 名患者接受了治疗，83% 的 Gleason 8-10，67% T3/T4，LN 中位数 2（范围 1-6），PET 阳性 LN 体积中位数 1.14 cc（范围 0.15-4.14） . 37% 的患者的 LN 超出了标准轮廓指南。平均 PET 阳性 LN 临床目标体积剂量范围为 73.3 至 85.9 Gy（中值 83.6 Gy）。中位随访 24 个月，2 年无失败生存率为 100%，2 年总生存率为 95.7%。48% 和 11% 的患者发生急性 1 级和 2 级 GI 毒性，72% 和 24% 的患者发生 GU 毒性。晚期 1、2 和 3 级 GI 毒性发生在 13、2 和 0%，而 GU 毒性发生在 28、13 和 4%。没有毒性可归因于高剂量 LN 加强。结论 PSMA PET 引导下对前列腺和累及 LN 进行高达 81 Gy 的 DE-IMRT 和长期 ADT，对于新诊断的 LN 阳性前列腺癌是一种很有前景的方法。在 PSMA PET 成像时代，LN 轮廓指南需要重新评估。