调强放疗总疗程时间延长对局部晚期鼻咽癌疗效的影响

Value of overall treatment time on the effect of intensity-modulated radiotherapy for locally advanced nasopharyngeal carcinoma

目的 探讨在调强放疗（IMRT）模式下总疗程时间（OTT）延长对局部晚期鼻咽癌疗效的影响.方法 对2001年5月至2007年4月在本中心首诊接受IMRT的376例T3-4N0-3M0期鼻咽癌患者进行回顾分析.以中位OTT为界分为OTT≤45 d和〉45 d两组并比较差异,用Cox回归模型行多因素预后分析,放疗时间与局部控制率关系采用直线回归分析.结果 全组OTT≤45 d和〉45 d组鼻咽2年局部控制率相似（94.9%和93.1%;χ2=2.83,P〉0.05）,T3期患者的也相似（96.3%和98.7%;χ2=2.18,P〉0.05）,T4期患者的不同（92.2%和83.1%;χ2=6.30,P〈0.05）.放疗中断发生在治疗开始3周前、3周后或3周前后的2年局部控制率相似（98%、96%或93%;χ2=2.21,P=0.531）.放化疗模式下OTT〉45 d组比OTT≤45 d组2年局部控制率低（93.1%和97.5%;χ2=4.69,P=0.030）.多因素分析显示OTT是T4期患者局部控制率的影响因素.直线回归分析显示T4期患者疗程每延长1 d,2年局部控制率大约下降2.7%.OTT≤45 d和〉45 d组的2年无瘤生存率、无远转生存率及总生存率均相似[84.1%和78.7%（χ2=0.02,P=0.881）、87.0%和86.1%（χ2=0.85,P=0.358）、91. 7%和92.2%（χ2=0.06,P=0.806）],T3及T4期患者的均也相似[83.7%和83.2%（χ2=0.07,P=0.798）、86.6%和85.7%（χ2=0.02,P=0.898）、93.7%和94.8%（χ2=0.03,P=0.862）及81.4%和72.3%（χ2=0.16,P=0.687）、82.6%和86.9%（χ2=1.78,P=0.182）、88.3%和87.5%（χ2=0.60,P=0.438）].多因素分析显示T分期、N分期是无瘤生存和总生存的影响因素,N分期是无远转生存率的影响因素.结论 IMRT模式下OTT延长将导致T4期鼻咽癌患者局部控制率降低,临床上应尽量避免疗程延长.

Objective To investigat the prognostic value of overall treatment time （OTT） for locally advanced nasopharyngeal carcinoma （NPC） treated with intensity-modulated radiation therapy （IMRT）.Methods From May 2001 to April 2007, 376 patients with locally advanced NPC treated with IMRT were retrospectively analyzed.All patients were divided into OTT≤45 days group and OTT 〉45 days group.The treatment outcomes between the two groups were analyzed.Results Between the groups with OTT≤45 days and OTT 〉 45 days, the 2-year local control rate （LCR） was 94.9% and 93.1% （χ2= 2.83, P 〉 0.05） for all patients, 96.3% and 98.7% （χ2=2.83, P〉0.05） for patients with T3 disease, 92.2% and 83.1%（χ2= 6.30, P 〈 0.05） for T4, and 93.1% and 97.5% （χ2= 4.69, P = 0.030） when chemotherapy was concurrently administered.The 2-year LCR was 98%, 96% and 93% （χ2= 2.20, P = 0.531） for patients with treatment interruption before, within and after the 3rd week of IMRT, The Cox regression analysis found that OTT was an independent prognostic factor for LCR in T4 disease.The Linear regression showed that the 2-year LCR was decreased by 2.7% per day of delay.Between the groups with OTT≤45 days and OTT 〉45days, the 2-year estimated disease-specific survival （DSS）, distant metastasis-free survival （DMFS） and overall survival （OS） were 84.1% vs.78.7% （χ2= 0.02, P = 0.881）, 87.0% vs.86.1% （χ2= 0.85,P = 0.358）, and 91.7% vs.92.2% （χ2= 0.06, P = 0.806）, respectively.The further stratified analysis found that the DSS, DMFS and OS were similar between the two groups in T3 （83.7% vs.83.2%, χ2=0.07, P=0.798;86.6% vs.85.7%,χ2=0.02, P = 0.898 ; and 93.7% vs.94.8%,χ2=0.03, P=0.862） and T4 disease （81.4% vs.72.3%, χ2= 0.16, P = 0.687 ;82.6% vs.86.9%, χ2= 1.78, P =0.182;and 88.3% vs.87.5% ,χ2=0.60, P =0.438）.In multivariate analysis, T-stage and N-stage were the independent prognostic factors for both DFS and OS, and N-stage was the independent prognostic factor for DMFS.Conclusions The prolongation of the overall treatment time decrease the local control of patients with T4 NPC.