鼻咽癌IMRT后腮腺区域失败分析

Failure in region of parotid gland after definitive intensity-modulated radiotherapy for Nasopharyngeal Carcinoma

目的讨论鼻咽癌IMRT后腮腺复发的潜在原因。方法回顾我院2005-2012年间鼻咽癌IMRT患者1096例，其中腮腺复发13例，可分析腮腺复发12例。以腮腺复发侧为病例组、腮腺健侧为对照组进行病例对照研究。分析腮腺失败与肿瘤侵犯范围、IMRT剂量分布、局部复发等因素之间关系。组间比较行爿。检验或Fisher’s精确概率法检验。结果11例患者原发鼻咽癌为Ⅲ-Ⅳ期，根治性IMRT后9例有局部区域残留。腮腺复发中位时间为16（8—43）个月。腮腺复发患者中8例位于腮腺浅叶、1例位于深叶，另外3例累及腮腺深、浅叶。腮腺复发见于原发肿瘤中心同侧（P=0．000）。腮腺复发侧颈部穿刺和（或）手术史较健侧多见（P=0．025）。腮腺复发多合并同侧颈淋巴结复发（67％：8％，P=0．003），并有合并同侧原发灶复发的趋势（42％：8％，P=0．059）。结论鼻咽癌IMRT后腮腺复发率很低。腮腺复发可能与鼻咽癌局部晚期、治疗后残留、颈部穿刺和（或）手术史，以及局部区域复发有关。IMRT导致腮腺区放疗低剂量可能是腮腺复发的重要原因。

To investigate the potential risk factors for parotid gland failure after intensity-modulated radiotherapy （IMRT） for nasopharyngeal carcinoma （NPC）. Methods The clinical data of 1096 NPC patients who underwent IMRT in our hospital from January 2005 to December 2012 were analyzed retrospectively. Among these patients, 13 patients experienced parotid gland recurrence, and the recurrence in 12 patients was analyzed. A case-control study was performed with the side of the parotid gland with recurrence as the case group and the side of the parotid gland without recurrence as the control group. The association of parotid gland failure with the extent of tumor invasion, IMRT dose distribution, and local recurrence was analyzed. The differences between groups were analyzed with X2 test or Fisher＇s the exact probability test. Results Among the 12 patients, 11 had stage III-IV primary NPC;after definitive IMRT, 9 had local tumor residues. The median time of parotid gland recurrence was 16 （8-43） months. Of all the patients who experienced recurrence, 8 had recurrence in the superficial lobe of the parotid gland, 1 in the deep lobe, and 3 in both superficial and deep lobes. Recurrence was in the same side of primary tumor （ P〈 0. 001 ）. Compared with the controls, the side of the parotid gland with recurrence had higher rate of cervical puncture/surgery （P= 0. 025）. Parotid gland recurrence was often complicated by ipsilateral lymph node recurrence （67% vs. 8%, P= O. 003 ） , as well as the tendency of ipsilateral primary lesion recurrence （42% vs. 8%;P=0.059）. Conclusions For NPC patients, the recurrence rate in the parotid gland is very low. Parotid gland recurrence may be related to locally advanced NPC, residues after treatment, the history of cervical puncture/surgery, and locoregional recurrence. The low radiotherapy dose in the parotid gland caused by IMRT may be an important reason for parotid gland recurrence.