University of Washington School of Medicine, Seattle, WA, USA.
Departments of Radiation Oncology and Neurosurgery, Alvord Brain Tumor Center, University of Washington, Seattle, WA, USA.
J Neurooncol. 2021 May;152(3):583-590. doi: 10.1007/s11060-021-03734-6. Epub 2021 Mar 22.
Criteria by the Radiologic Assessment in Neuro-Oncology (RANO) group outline the diagnosis of pseudoprogression (Ps) after photon therapy for gliomas based on timing and location. We noted that patients receiving proton therapy manifested radiographic changes that appear different than Ps after photon therapy, which could be interpreted as tumor progression. In this study, we retrospectively reviewed MR imaging after proton or photon radiation for gliomas. We propose criteria to characterize proton pseudoprogression (ProPs) as distinct from Ps seen after photons.
Post-treatment MR imaging, clinical and pathological data of low grade glioma patients were reviewed. Overall, 57 patients receiving protons were reviewed for the presence of ProPs, and 43 patients receiving photons were reviewed for any equivalent imaging changes. Data collected included the location and timing of the new enhancement, tumor grade, molecular subtype, chemotherapy received, and clinical symptoms.
Fourteen patients (24.6%) had new enhancement following radiation therapy that was unique to treatment with protons. The mean time to development of the ProPs was 15.4 months (7-27 months). We established the following criteria to characterize ProPs: located at the distal end of the proton beam; resolves without tumor-directed therapy; and subjectively multifocal, patchy, and small (< 1 cm). In the group receiving photons, none had changes that met our criteria for ProPs.
Patients who receive protons have unique imaging changes after radiation therapy. ProPs could be mistaken for tumor progression, but typically resolves on follow up. Further studies are needed to understand the radiobiology and pathophysiology underlying these imaging changes.
放射肿瘤学评估 (RANO) 小组制定的标准根据时间和位置概述了光子治疗后神经胶质瘤假性进展 (Ps) 的诊断。我们注意到接受质子治疗的患者表现出的影像学变化与光子治疗后的 Ps 不同，这可能被解释为肿瘤进展。在这项研究中，我们回顾性地审查了质子或光子放射治疗后神经胶质瘤的磁共振成像。我们提出了特征性质子假性进展 (ProPs) 的标准，使其与光子治疗后出现的 Ps 区分开来。
回顾性分析低级别胶质瘤患者治疗后磁共振成像、临床和病理资料。共有 57 例接受质子治疗的患者被评估是否存在 ProPs，43 例接受光子治疗的患者被评估是否存在任何等效的影像学变化。收集的数据包括新增强的位置和时间、肿瘤分级、分子亚型、接受的化疗以及临床症状。
14 例（24.6%）患者在接受质子治疗后出现了新的增强，这是质子治疗特有的。ProPs 的平均发生时间为 15.4 个月（7-27 个月）。我们建立了以下标准来描述 ProPs：位于质子束的末端；无需针对肿瘤的治疗即可缓解；并且主观上呈多灶性、斑片状和小（<1cm）。在接受光子治疗的患者中，没有任何变化符合我们对 ProPs 的标准。
接受质子治疗的患者在放射治疗后会出现独特的影像学变化。ProPs 可能被误认为肿瘤进展，但通常在随访中会缓解。需要进一步的研究来了解这些影像学变化的放射生物学和病理生理学基础。
