Bulens Philippe, Thomas Melissa, Deroose Christophe M, Haustermans Karin
Department of Oncology, KU Leuven-University of Leuven, Leuven, Belgium.
Department of Radiation Oncology, University Hospitals Leuven, Leuven, Belgium.
Q J Nucl Med Mol Imaging. 2018 Dec;62(4):385-403. doi: 10.23736/S1824-4785.18.03081-9. Epub 2018 Jun 4.
Radiotherapy is a cornerstone in the multimodality treatment of several gastrointestinal (GI) tumors. Positron-emission tomography (PET) has an established role in the diagnosis, response assessment and (re-)staging of these tumors. Nevertheless, the value of PET in adaptive radiotherapy remains unclear. This review focuses on the role of PET in adaptive radiotherapy, i.e. during the treatment course and in the delineation process.
The MEDLINE database was searched for the terms ("Radiotherapy"[Mesh] AND "Positron-Emission Tomography"[Mesh] AND one of the site-specific keywords, yielding a total of 1710 articles. After abstract selection, 27 papers were identified for esophageal neoplasms, 1 for gastric neoplasms, 9 for pancreatic neoplasms, 6 for liver neoplasms, 1 for biliary tract neoplasms, none for colonic neoplasms, 15 for rectal neoplasms and 12 for anus neoplasms.
The use of PET for truly adaptive radiotherapy during treatment for GI tumors has barely been investigated, in contrast to the potential of the PET-defined metabolic tumor volume for optimization of the target volume. The optimized target definition seems useful for treatment individualization such as focal boosting strategies in esophageal, pancreatic and anorectal cancer. Nevertheless, for all GI tumors, further investigation is needed.
In general, too little data are available to conclude on the role of PET imaging during radiotherapy for ART strategies in GI cancer. On the other hand, based on the available evidence, the use of biological imaging for target volume adaptation seems promising and could pave the road towards individualized treatment strategies.
放射治疗是多种胃肠道（GI）肿瘤多模式治疗的基石。正电子发射断层扫描（PET）在这些肿瘤的诊断、疗效评估及（再）分期方面已确立了其作用。然而，PET在自适应放射治疗中的价值仍不明确。本综述聚焦于PET在自适应放射治疗中的作用，即在治疗过程及靶区勾画过程中的作用。
在MEDLINE数据库中检索了以下术语（“放射治疗”[医学主题词] AND “正电子发射断层扫描”[医学主题词] AND 特定部位的关键词之一），共检索到1710篇文章。经过摘要筛选，确定了27篇关于食管肿瘤的论文、1篇关于胃肿瘤的论文、9篇关于胰腺肿瘤的论文、6篇关于肝脏肿瘤的论文、1篇关于胆道肿瘤的论文、0篇关于结肠肿瘤的论文、15篇关于直肠肿瘤的论文和12篇关于肛门肿瘤的论文。
与PET定义的代谢肿瘤体积用于优化靶区体积的潜力相比，PET在胃肠道肿瘤治疗期间用于真正的自适应放射治疗的研究几乎没有。优化的靶区定义似乎有助于治疗个体化，如在食管癌、胰腺癌和肛管直肠癌中的局部加量策略。然而，对于所有胃肠道肿瘤，仍需要进一步研究。
总体而言，关于PET成像在胃肠道癌自适应放射治疗策略的放射治疗过程中的作用，可用数据太少，无法得出结论。另一方面，基于现有证据，使用生物成像进行靶区体积适配似乎很有前景，可为个体化治疗策略铺平道路。
