Background

Stereotactic body radiotherapy (SBRT) and elective nodal radiotherapy (ENRT) are being investigated as metastasis-directed treatments in oligorecurrent prostate cancer (PC); however, comparative data are still lacking.

Objective

To compare outcome and toxicity between both treatments. Primary endpoint was metastasis-free survival, adjusted for selected variables (aMFS).

Design, setting, and participants

This was a multi-institutional, retrospective analysis of 506 (SBRT: 309, ENRT: 197) patients with hormone-sensitive nodal oligorecurrent PC (five or fewer lymph nodes (LNs; N1/M1a), treated between 2004 and 2017. Median follow-up was 36 mo (interquartile range 23–56).

Intervention

SBRT was defined as a minimum of 5 Gy per fraction to each lesion with a maximum of 10 fractions. ENRT was defined as a minimum dose of 45 Gy in up to 25 fractions to the elective nodes, with or without a simultaneous boost to the suspicious node(s). The choice of radiotherapy (RT) was at the discretion of the treating physician, with treatments being unbalanced over the centers.

Outcome measurements and statistical analysis

In total, 506 patients from 15 different treatment centers were included. Primary treatment was radical prostatectomy, RT, or their combination. Nodal recurrences were detected by positron emission tomography/computer tomography (97%) or conventional imaging (3%). Descriptive statistics was used to summarize patient characteristics.

Results and limitations

ENRT was associated with fewer nodal recurrences compared with SBRT (p < 0.001). In a multivariable analysis, patients with one LN at recurrence had longer aMFS after ENRT (hazard ratio: 0.50, 95% confidence interval 0.30–0.85, p = 0.009). Late toxicity was higher after ENRT compared with that after SBRT (16% vs. 5%, p < 0.01). Limitations include higher use of hormone therapy in the ENRT cohort and nonstandardized follow-up.

Conclusions

ENRT reduces the number of nodal recurrences as compared with SBRT, however at higher toxicity. Our findings hypothesize that ENRT should be preferred to SBRT in the treatment of nodal oligorecurrences. This hypothesis needs to be evaluated in a randomized trial.

Patient summary

This study investigated the difference between stereotactic and elective nodal radiotherapy in treating limited nodal metastatic prostate cancer. Nodal relapse was less frequent following elective nodal radiotherapy than following stereotactic body radiotherapy, and thus elective nodal radiotherapy might be the preferred treatment.

中文翻译：

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转移导向疗法治疗淋巴结少流性前列腺癌：立体定向身体放疗和选择性淋巴结放疗的结果和毒性比较的多机构分析。

背景

立体定向身体放疗（SBRT）和选择性淋巴结放疗（ENRT）被作为转移性治疗在少复发性前列腺癌（PC）中进行了研究。但是，仍然缺乏比较数据。

客观的

比较两种治疗的结果和毒性。主要终点是无转移生存期，并根据选择的变量（aMFS）进行了调整。

设计，设置和参与者

这是对2004年至2017年期间治疗的506例激素敏感型结节性少尿复发性PC（五个或更少淋巴结（LN； N1 / M1a）患者）进行的多机构，回顾性分析。上升为36 mo（四分位间距23-56）。

干涉

SBRT定义为每个病变的每个部分最少5 Gy，最多10个部分。ENRT被定义为对选择性淋巴结的最小剂量为45 Gy（最多25个分数），同时增加或不同时增加可疑淋巴结。放射治疗（RT）的选择由主治医师决定，各中心之间的治疗不平衡。

成果测量和统计分析

总共包括来自15个不同治疗中心的506名患者。主要治疗方法是根治性前列腺切除术，RT或它们的组合。通过正电子发射断层扫描/计算机断层扫描（97％）或常规成像（3％）检测到淋巴结复发。描述性统计用于总结患者特征。

结果与局限性

与SBRT相比，ENRT与较少的淋巴结复发相关（p  <0.001）。在多变量分析中，一次EN复发的LN患者在ENRT后的aMFS较长（危险比：0.50，95％置信区间0.30-0.85，p  = 0.009）。ENRT后的晚期毒性高于SBRT后（16％比5％，p  <0.01）。局限性包括在ENRT队列中更多地使用激素治疗和不规范的随访。

结论

与SBRT相比，ENRT减少了淋巴结复发的次数，但是毒性更高。我们的发现假设，在结节性少尿复发的治疗中，应首选ENRT替代SBRT。该假设需要在随机试验中进行评估。

病人总结

这项研究调查了立体定向和选择性淋巴结放疗在治疗局限性淋巴结转移性前列腺癌中的区别。选择性结节放疗后的结节复发频率比立体定向身体放疗后少，因此选择性结节放疗可能是首选治疗方法。