Liskamp C P, Donswijk M L, van der Poel H G, Schaake E E, Vogel W V
Department of Radiation Oncology, NKI-AVL, Amsterdam, The Netherlands.
Department of Nuclear Medicine, NKI-AVL, Amsterdam, The Netherlands.
Clin Transl Radiat Oncol. 2020 Feb 26;22:9-14. doi: 10.1016/j.ctro.2020.02.006. eCollection 2020 May.
Biochemical failure after external beam radiotherapy (RT) for node-positive prostate cancer (PC) frequently involves nodal recurrences, in most cases out of field. This raises the question if current RTOG-based elective nodal fields can still be considered optimal. Modern diagnostic tools like PSMA PET/CT and choline PET/CT can visualize nodal recurrences with unprecedented accuracy. We evaluated recurrence patterns on PET/CT after RT for PC, with the aim to explore options for improved nodal target definition.
Data of all patients treated with curative intent EBRT for PC in NKI-AVL from 2008 to 2018 were retrospectively reviewed. EBRT comprised 70 Gy to the prostate or 66-70 Gy to the prostate bed, 60 Gy to involved nodes, and 52,5-56 Gy (46 Gy EQD2) to RTOG-based elective nodal fields, in 35 fractions. Locations of recurrences on PET/CT were noted, and nodal locations were correlated with the applied EBRT fields.
42 patients received PSMA (28) or choline (14) PET/CT at biochemical recurrence. 35 patients (83%) had a positive scan. At their first positive scan 17 patients had nodal metastasis, in some cases together with a local recurrence or distant disease. In-field nodal recurrences were uncommon (n = 3). Out-field nodal recurrences occurred more frequently (n = 14), with the majority (n = 12) just above the elective nodal field. These nodes were the single area of detectable failure in 6 patients (14%).
Current RT with RTOG-based nodal fields for PC provides good in-field tumour control, but frequent out-field nodal recurrences suggest missed microscopic locations. Expanding elective fields to include the aorta bifurcation may prolong recurrence-free survival. Future research must address whether the potential benefits of this strategy outbalance additional toxicity.
对于淋巴结阳性前列腺癌（PC），外照射放疗（RT）后的生化失败通常涉及淋巴结复发，在大多数情况下是野外复发。这就提出了一个问题，即目前基于美国放射肿瘤学组（RTOG）的选择性淋巴结照射野是否仍可被视为最佳方案。像前列腺特异性膜抗原（PSMA）正电子发射断层扫描/计算机断层扫描（PET/CT）和胆碱PET/CT这样的现代诊断工具能够以前所未有的准确性显示淋巴结复发情况。我们评估了PC放疗后PET/CT上的复发模式，旨在探索改进淋巴结靶区定义的方案。
回顾性分析了2008年至2018年在荷兰癌症研究所 - 阿姆斯特丹自由大学医学中心（NKI - AVL）接受根治性意图的PC调强适形放疗（EBRT）的所有患者的数据。EBRT包括对前列腺给予70 Gy或对前列腺床给予66 - 70 Gy，对受累淋巴结给予60 Gy，以及对基于RTOG的选择性淋巴结照射野给予52.5 - 56 Gy（等效剂量2为46 Gy），分35次照射。记录PET/CT上复发的位置，并将淋巴结位置与所应用的EBRT照射野相关联。
42例患者在生化复发时接受了PSMA（28例）或胆碱（14例）PET/CT检查。35例患者（83%）扫描结果为阳性。在首次阳性扫描时，17例患者有淋巴结转移，在某些情况下同时伴有局部复发或远处疾病。野外淋巴结复发并不常见（n = 3）。野外淋巴结复发更频繁（n = 14），大多数（n = 12）位于选择性淋巴结照射野上方。这些淋巴结是6例患者（14%）唯一可检测到的失败区域。
目前基于RTOG淋巴结照射野的PC放疗能很好地控制野外肿瘤，但频繁的野外淋巴结复发提示存在遗漏的微小病灶部位。扩大选择性照射野以包括主动脉分叉处可能会延长无复发生存期。未来的研究必须探讨该策略的潜在益处是否超过额外的毒性。
