磁共振成像RTOG分区在鼻咽癌淋巴结转移中的诊断价值

Value of Radiation Therapy Oncology Group guidelines based on MR imaging in diagnosing lymph node metastasis of nasopharyngeal carcinoma

背景与目的:美国肿瘤放射治疗协会(Radiation Therapy Oncology Group,RTOG)等组织联合发表了对于头颈部肿瘤的淋巴结分区方法及N0期病例亚临床靶区勾画的推荐标准,但对于N+的患者是否同样适用没有明确的定论。本研究旨在探讨RTOG分区对勾画鼻咽癌淋巴结转移颈部靶区的价值。方法:收集伴有淋巴结转移的初治鼻咽鳞癌患者254例,全部病例进行常规鼻咽部MRI平扫及增强检查,采用RTOG推荐的头颈部肿瘤淋巴结转移的分区方法进行淋巴结分区。结果:RTOG分区的标志在横断位MRI图像上均清晰可辨。254例患者中,107例(42.1%)出现淋巴结坏死,78例(30.7%)有包膜外侵犯,4例(1.6%)出现跳跃性转移。51例(20.1%)患者出现了RTOG分区以外的淋巴结侵犯,Ⅱb区上界以上区域有42例,斜方肌前缘以后的区域有6例受累,Ⅳ区的下界以下有23例。51例患者中,20例为两处出现了RTOG分区以外的淋巴结侵犯。本组未见单纯发生在RTOG分区以外的淋巴结转移病例。结论:MRI可以用来进行颈部淋巴结的RTOG分区;应用RTOG分区勾画鼻咽癌淋巴结转移的颈部靶区时,边界应适当放宽。

Background and Objective： Radiation Therapy Oncology Group （RTOG） and other major cooperative groups endorse the consensus guidelines for the delineation of the node levels in stage NO cases. But it is unclear if these guidelines can be extrapolated to N＋ cases. This study was to explore the value of RTOG guidelines in delineating cervical target volumes for nasopharyngeal carcinoma （NPC） patients with lymph node metastasis. Methods. Conventional magnetic resonance imaging （MRI） of the nasopharynx, including plain and contrast enhanced sequences, was performed on 254 naive NPC patients. The lymph nodes were divided into six cervical levels plus retropharyngeal nodes （RN） according to RTOG guidelines proposed in 2003. Results= Anatomic boundaries of node levels were observed clearly on MRI. Of the 254 patients, 107 （42.1%） had obvious lymph node necrosis, 78 （30.7%） had extracapsular nodal spread, four （1.6%） had skipped metastasis. The levels of lymph node metastases in 51 （20.1%） patients were beyond RTOG guidelines, 42 of which were above cranial level Ⅱ b, six were behind the anterior edge of the trapezius muscle, and 23 were below the caudal of level Ⅳ ; 20 patients had two regions of lymph node metastases beyond RTOG guidelines. No patient only with lymph node metastasis beyond RTOG guidelines was found. Conclusions= MRI is feasible to diagnose cervical node metastasis with RTOG guidelines. The boundaries of node levels should be enlarged rationally when delineating target volumes for the N＋ NPC patients according to RTOG guidelines.