根据国际指南，探讨鼻咽癌（NPC）患者在调强放疗（IMRT）期间保留Ib水平的可行性。
在我们组中接受明确IMRT的组织学证实的NPC患者是该分析的候选人。根据选择性覆盖Ib级的国际准则的建议设计用于分析的其他合格标准。分析以区域无复发生存率（RRFS）和Ib级复发率为重点的生存结局。
共纳入450名患者，根据我们的协议，由于国际准则的前三项原则，其中60人获得了Ib级的IMRT。值得注意的是，Ib级受累的患者将接受超声引导穿刺，只有那些病理结果阳性的患者才会接受Ib水平覆盖的IMRT.对于其余390例仅符合最后两个标准和/或Ib级受累且病理结果阴性的患者，Ib级-保留IMRT已交付，中位随访时间为112个月（6至194个月），报告的5年和10年RRFS分别为95.4%和92.9%，分别。22例患者在检查时发生区域性复发（中位数为44.5个月），只有4例(4/390,1.03%)被记录为Ib级复发.
对于只有II级参与ECE的患者，保留Ib级IMRT应该是安全可行的。和/或在II级具有大于2厘米的MAD，和/或Ib级参与病理结果阴性。应进一步进行精心设计的多中心前瞻性试验。
To investigate the feasibility of level Ib sparing in selected nasopharyngeal carcinoma (NPC) patients during intensity-modulated radiation therapy (IMRT) based on the International
Guideline.
Patients with histologically-proven NPC who received definitive IMRT at our group were candidates for this analysis. Other eligibility criteria for analysis were designed according to the recommendation of International
Guideline for selective coverage of level Ib. Survival outcomes focused on regional recurrence-free survival (RRFS) and level Ib recurrence rate were analyzed.
A total of 450 patients were included, 60 of them received level Ib-covering IMRT due to the first three principles of the International
Guideline according to our protocol. Of note, patients with level Ib involvement would receive ultrasound guided puncture, only those with positive pathological results would undergo level Ib-covering IMRT. For the remaining 390 patients who only fulfilled the last two criteria and/or level Ib involvement with negative pathological results, level Ib-sparing IMRT was delivered, with a median follow-up time of 112 months (range 6 to 194 months), reported 5- and 10-year RRFS were 95.4% and 92.9%, respectively. Twenty-two patients occurred regional recurrence at censorship (median 44.5 months), only 4(4/390, 1.03%) were recorded as level Ib recurrence.
Level Ib-sparing IMRT should be safe and feasible for patients who only had level II involvement with ECE, and/or had a MAD of greater than 2 cm in level II, and/or level Ib involvement with negative pathological results. Further well-designed multi-center prospective trials should be conducted.
