Aims

Due to its physical advantages over photon radiotherapy, proton beam therapy (PBT) has the potential to improve outcomes from oesophageal cancer. However, for many tumour sites, high-quality evidence supporting PBT use is limited. We carried out a systematic review of published literature of PBT in oesophageal cancer to ascertain potential benefits of this technology and to gauge the current state-of-the-art. We considered if further evaluation of this technology in oesophageal cancer is desirable.

Materials and methods

A systematic literature search of Medline, Embase, Cochrane Library and Web of Science using structured search terms was carried out. Inclusion criteria included non-metastatic cancer, full articles and English language studies only. Articles deliberating technical aspects of PBT planning or delivery were excluded to maintain a clinical focus. Studies were divided into two sections: dosimetric and clinical studies; qualitatively synthesised.

Results

In total, 467 records were screened, with 32 included for final qualitative synthesis. This included two prospective studies with the rest based on retrospective data. There was heterogeneity in treatment protocols, including treatment intent (neoadjuvant or definitive), dose, fractionation and chemotherapy used. Compared with photon radiotherapy, PBT seemed to reduce dose to organs at risk, especially lung and heart, although not for all reported parameters. Toxicity outcomes, including postoperative complications, were reduced compared with photon radiotherapy. Survival outcomes were reported to be at least comparable with photon radiotherapy.

Conclusion

There is a paucity of high-quality evidence supporting PBT use in oesophageal cancer. Wide variation in intent and treatment protocols means that the role and ‘gold-standard’ treatment protocol are yet to be defined. Current literature suggests significant benefit in terms of toxicity reduction, especially in the postoperative period, with comparable survival outcomes. PBT in oesophageal cancer holds significant promise for improving patient outcomes but requires robust systematic evaluation in prospective studies.

中文翻译：

---

质子束治疗食道癌的前景：对剂量学和临床结果的系统评价

目标

由于其相对于光子放射疗法的物理优势，质子束疗法 (PBT) 具有改善食管癌预后的潜力。然而，对于许多肿瘤部位，支持 PBT 使用的高质量证据是有限的。我们对已发表的食道癌 PBT 文献进行了系统评价，以确定该技术的潜在益处并评估当前的最新技术水平。我们考虑是否需要进一步评估该技术在食道癌中的应用。

材料和方法

使用结构化检索词对 Medline、Embase、Cochrane Library 和 Web of Science 进行了系统的文献检索。纳入标准仅包括非转移性癌症、全文和英语语言研究。讨论 PBT 计划或交付的技术方面的文章被排除在外，以保持临床重点。研究分为两个部分：剂量学研究和临床研究；定性综合。

结果

总共筛选了 467 条记录，其中 32 条用于最终定性综合。这包括两项前瞻性研究，其余研究基于回顾性数据。治疗方案存在异质性，包括治疗意图（新辅助或确定）、剂量、分割和使用的化疗。与光子放射疗法相比，PBT 似乎可以减少风险器官的剂量，尤其是肺和心脏，尽管并非针对所有报告的参数。与光子放疗相比，毒性结果（包括术后并发症）减少了。据报道，生存结果至少与光子放疗相当。

结论

支持 PBT 用于食道癌的高质量证据很少。意图和治疗方案的广泛变化意味着角色和“黄金标准”治疗方案尚未确定。目前的文献表明，在降低毒性方面有显着益处，特别是在术后期间，具有可比的生存结果。食道癌中的 PBT 对改善患者预后有很大的希望，但需要在前瞻性研究中进行强有力的系统评估。