Willmann Jonas, Rimner Andreas
Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
J Thorac Dis. 2018 Aug;10(Suppl 21):S2555-S2564. doi: 10.21037/jtd.2018.01.154.
The role of radiation therapy (RT) in thymic malignancies has long been subject to considerable controversy. The main role for RT is in the setting of adjuvant therapy after surgical tumor resection, especially in advanced or incompletely resected cases. However, recent studies with larger patient numbers and cleaner study populations than previous studies have indicated a potentially clearer than previously assumed benefit after post-operative RT (PORT) even for completely resected patients with earlier stages of thymoma. In marginally resectable patients RT may be used in combination with neoadjuvant chemotherapy to shrink tumors and thereby potentially enable resection. In unresectable patients concurrent or sequential chemotherapy and RT can be employed as the definitive nonsurgical approach. The tendency of thymic tumors to recur in the pleural space highlights the necessity for more effective approaches to identify and treat high risk patients. Experiences in other pleural malignancies may pave the way to novel treatment modalities, for example pleural IMRT. The role of these techniques in thymic malignancies has yet to be determined and is not advisable at the current time outside of a clinical study. As the disease often takes an indolent course with excellent long-term local control (LC) and survival, late toxicities related to radiation of the mediastinum and adjacent organs at risk (OARs) have to be taken into consideration and may jeopardize the benefit patients experience from RT, especially in younger patients with a long-anticipated life expectancy. Radiation techniques, such as intensity modulated RT (IMRT) and proton beam therapy (PBT), have substantially reduced the exposure of OARs to ionizing radiation which is expected to translate into reduced long-term toxicities. Hence, the risk-benefit ratio of RT in early stage thymoma patients may be shifted favorably.
放射治疗（RT）在胸腺恶性肿瘤中的作用长期以来一直备受争议。RT的主要作用是在手术切除肿瘤后进行辅助治疗，特别是在晚期或切除不完全的病例中。然而，与以往研究相比，近期纳入患者数量更多且研究人群更纯粹的研究表明，即使对于早期胸腺瘤且已完全切除的患者，术后放疗（PORT）后的获益可能比之前认为的更明确。对于边缘可切除的患者，RT可与新辅助化疗联合使用以缩小肿瘤，从而有可能实现切除。对于不可切除的患者，可采用同步或序贯化疗及RT作为确定性的非手术治疗方法。胸腺肿瘤在胸腔内复发的倾向凸显了采用更有效方法来识别和治疗高危患者的必要性。其他胸腔恶性肿瘤的治疗经验可能为新的治疗模式铺平道路，例如胸腔调强放疗（IMRT）。这些技术在胸腺恶性肿瘤中的作用尚未确定，目前在临床研究之外不建议使用。由于该疾病通常病程进展缓慢，具有良好的长期局部控制（LC）和生存率，因此必须考虑与纵隔及相邻危险器官（OARs）放疗相关的晚期毒性，这可能会危及患者从RT中获得的益处，尤其是对于预期寿命较长的年轻患者。诸如调强放疗（IMRT）和质子束治疗（PBT）等放射技术已大幅减少了OARs对电离辐射的暴露，预计这将转化为长期毒性的降低。因此，早期胸腺瘤患者RT的风险效益比可能会向有利方向转变。
