EBV DNA定量分析在监测鼻咽癌转移和复发中的临床意义

背景与目的:EB病毒(Epstein-Barrvirus,EBV)感染与鼻咽癌关系密切,近年来,有报道鼻咽癌患者血浆/血清中可检测到游离EBVDNA,但血浆EBVDNA水平对判断放疗后鼻咽癌患者转移、复发的临床意义尚缺少大宗研究报道。本研究定量检测鼻咽癌放疗后随诊患者血浆EBVDNA含量,探讨其在监测鼻咽癌转移、复发中的临床意义。方法:选择在中山大学肿瘤防治中心门诊随诊的放疗后鼻咽癌患者90例,用荧光定量PCR方法检测血浆EBVDNA含量,比较转移、复发与持续缓解患者血浆EBVDNA拷贝数。结果:放疗后转移或复发患者血浆EBVDNA的检出率为96.7%(29/30),中位拷贝数为2650copies/ml(0～5900000copies/ml);而持续缓解组患者血浆EBVDNA检出率12%(7/60),中位拷贝数为0copy/ml(0～71000copies/ml),差异均有统计学意义(P<0.01)。3例临床持续缓解但有血浆EBVDNA升高患者,在随后的3～4个月随访中,证实有肿瘤转移或复发。结论:血浆EBVDNA李宇红,等.EBVDNA定量分析在646定量检测可能成为监测放疗后鼻咽癌患者肿瘤转移、复发的敏感肿瘤标记物。     

血浆EBV DNA水平测定在监测鼻咽癌放疗后复发、转移中的临床意义

目的 探讨定量分析血浆EBV DNA水平在监测鼻咽癌复发、转移中的临床意义。方法 应用荧光定量PCR技术（real-time PCR）,检测360例根治放疗后鼻咽癌患者血浆EBV DNA水平,并与临床及影像学检查结果 比较。结果 360例患者中87例血浆EBV DNA检测阳性,273例阴性。在87例检出阳性者中,25例证实为临床复发,45例证实为远处转移,故其预测肿瘤进展阳性预测值为80%（70/87）。在273例血浆EBV DNA检测阴性患者中,共有17例复发和4例转移,故其阴性预测值为92%（252/273）。总计91例肿瘤进展患者中70例血浆EBV DNA阳性,其中复发42例,25例血浆EBV DNA阳性;转移49例,45例血浆EBVDNA阳性。269例临床缓解患者中17例血浆EBV DNA阳性,故其敏感性、特异性、假阳性率和假阴性率分别为77%（70/91）、94%（252/269）、6%（17/269）、23%（21/91）、90%（322/360）。复发患者、转移患者、肿瘤进展患者和临床缓解患者EBVDNA阳性率和中位拷贝数分别为：60%,4700 copies/ml;92%,425000 copies/ml;77%,38000 copies/ml;6%,〈500copies/ml。复发患者与转移患者比较、肿瘤进展患者与临床进展患者比较,血浆EBV DNA阳性率和中位拷贝数均有显著性差异。结论 血浆EBV DNA水平的检测是监测放疗后鼻咽癌患者转移、复发的有效指标。     

鼻咽癌患者血浆游离EBV/DNA的定量检测及其临床意义

目的:探讨血浆EBV/DNA定量分析,在鼻咽癌早期诊断、临床分期、预后判断和监测放疗后转移复发中的临床意义.方法:采用荧光定量PCR方法定量检测经病理确诊为鼻咽癌的120例初治、90例放疗后随诊患者,其中包括60例放疗后持续缓解,30例远处转移和局部复发患者的血浆EBV/DNA含量.结果:初治、远处转移和局部复发的鼻咽癌患者血浆中游离的EBV/DNA检出率分别为96.0%、95.0%和100%,显著高于治疗后持续缓解鼻咽癌患者、健康对照者和非鼻咽癌的肿瘤患者;初治鼻咽癌患者各TNM分期之间血浆EBV/DNA拷贝数有显著统计学差异,晚期患者(Ⅲ Ⅳ)期血浆EBV/DNA中位拷贝数显著高于早期患者(I Ⅱ)期;初治患者治疗后已出现局部和远处转移者.治疗前血浆EBV/DNA中位数显著高于尚未出现复发转移患者:初治患者治疗前血浆EBV/DNA≥40 000拷贝/ml与＜40 000拷贝/ml两个水平,患者22个月无复发生存率分别为46.1%和92.9%,有显著统计学差异;放疗后复发、转移鼻咽癌患者血浆EBV/DNA的中位拷贝数显著高于治疗后持续缓解患者.结论:采用荧光定量PCR方法检测鼻咽癌患者血浆中游离的EBV/DNA是一种敏感可靠的方法,对于鼻咽癌早期诊断、鉴别诊断、分期、判断预后、监测治疗后复发和远处转移具有重要的临床意义,有可能成为鼻咽癌的血清肿瘤标记物.     

鼻咽癌患者血浆EBVDNA水平和VCA—IgA检测的临床意义

目的：探讨鼻咽癌患者血浆EBVDNA水平和VCA—IgA联合检测对鼻咽癌早期诊断的临床价值。方法：用荧光定量PCR方法检测血浆EBVDNA水平，常规免疫酶法检测VCA—IgA抗体滴度。结果：68例鼻咽癌患者中，EBVDNA阳性率95．59％，中位拷贝数93× 10^4 copies／ml，VCA—IgA抗体阳性率92．65％，抗体滴度≥1：20；其他头颈肿瘤36例中，EBVDVA阳性率5．56％，中位拷贝数为0copies／ml，VCA—IgA抗体阳率36．11％，阳性滴度均≤1：20；健康对照组EBVDNA阳性率为35．56％，其滴度除3例≥1：40外，余均≤1：20。鼻咽癌患者中EBVDNA和VCA—IgA抗体阳性率显著高于对照组。结论：进-步证实EBV与鼻咽癌有密切关系；EBVDNA水平和VCA—IgA抗体滴度联合检测，有助于鼻咽癌的早期辅助诊断。     

血浆EBV DNA定量分析在监测鼻咽癌患者复发和转移中的价值

目的 探讨血浆EB病毒DNA(EBV DNA)含量在监测鼻咽癌患者放疗后复发和转移中的临床价值.方法 采用荧光定量PCR方法 检测81例放疗后随诊的鼻咽癌患者血浆EBV DNA含量,比较缓解组与复发、转移组血浆EBV DNA差异.结果 放疗后缓解组患者血浆EBV DNA阳性率为15.7%,中位拷贝数为0 copy/ml;放疗后复发或转移组患者血浆EBV DNA阳性率93.3%,中位拷贝数6 432 copies/ml,差异均有显著性(P<0.001).结论 血浆EBV DNA定量检测有可能成为监测鼻咽癌患者放疗后复发、转移的肿瘤标记物.     

鼻咽癌患者血浆EB病毒DNA水平与肿瘤复发的关系

目的 :探讨鼻咽癌患者放射治疗后血浆EB病毒 (EBV)DNA水平与肿瘤复发的关系。方法 :11例临床缓解期患者和 9例临床复发患者分别抽血 3ml。所有的标本均采用荧光定量PCR的方法 ,在PE770 0型检测仪上定量检测血浆标本中EB病毒DNA的含量。结果 :肿瘤复发组 89% ( 8/ 9)的患者血浆中可检测到高拷贝数的EB病毒DNA ,中位浓度为4 70 0 0 0 (copies/ml) ,在临床缓解组患者中 ,仅 9% ( 1/ 11)的患者血浆中可检测到较高拷贝数的EB病毒DNA ,中位浓度为 0(copies/ml)。两组阳性率及中位浓度的比较均有显著性差异 (P <0 0 0 1)。结论 :鼻咽癌患者血浆EBVDNA水平与肿瘤复发关系密切 ,值得进一步研究。     

血浆EB病毒DNA浓度预测鼻咽癌远处转移的研究

背景与目的：鼻咽癌治疗失败的主要原因之一是远处转移,近年多项放化疗综合治疗的临床研究未显示出明显的远处转移率的降低和远期生存的获益,综合治疗适宜个体及最佳模式尚未确立。血浆EB病毒DNA（EBV DNA）浓度是一项能反映鼻咽癌分期、治疗反应、预后的灵敏、特异的分子生物学指标。我们设计此前瞻性研究。探讨通过鼻咽癌患者血浆EBV DNA浓度预测远处转移的发生．为个体化的综合治疗模式的选择提供分子学指标。方法：69例初治鼻咽癌患者分别在治疗前和治疗结束时采用荧光定量PCR方法检测血浆EBV DNA浓度。所有患者按计划随访。进行远期疗效及生存的评价。Kaplan-Meier法计算无转移生存率及总生存率,多因素分析用Cox回归模型。结果：远处转移患者治疗前血浆EBV DNA中位浓度（27 000copies／m1）及治疗后EBVDNA检出率（55．56％）均高于持续缓解者（4 000 copies／ml,5．56％）及局部复发者（3 850 copies／ml,0％）（P值分别为0．039,0．001）。以治疗前20 000 copies／ml、治疗后0 copies／ml为界值点．EBV DNA低浓度患者的无复发生存率、无转移生存率及总生存率均高于高浓度患者,差异有显著性。Cox回归分析显示治疗前EBV DNA浓度（P=0．050,RR=3．95）、治疗后EBVDNA浓度（P=0．001,RR=11．74）均是影响无转移生存的危险因素。进一步将患者治疗前后EBVDNA浓度变化综合进行生存分析,结果表明治疗后EBV DNA浓度能否降到0是影响无转移生存最重要的预后因素（P=0．000）。结论：鼻咽癌患者治疗前、后血浆EBV DNA浓度,尤其是治疗后能否降到0．能预测远处转移的发生,有望为放化综合治疗筛选高危患者,指导放化结合模式的选择。     

血浆EBV DNA检测在鼻咽癌诊疗中的研究新进展

鼻咽癌是中国南方地区最常见的恶性肿瘤之一,其主要发病因素包括遗传易感性、饮食因素和EB病毒（Epstein-Barr vi? rus,EBV）感染。鼻咽癌患者血浆中存在持续阳性的EBV DNA,其拷贝数与肿瘤的分期相关,有效治疗后迅速下降,复发和转移时再次升高。越来越多的研究显示,血浆EBV DNA检测在鼻咽癌早期诊断和筛查、肿瘤复发和转移诊断、预后判断以及个体化治疗等方面具有较大的价值。本文就以上问题进行分析总结以供临床和未来的研究参考。      

鼻咽癌患者血浆EBV-DNA、血清CYFRA21-1、TSGF的检测及临床应用

目的:探讨和比较血浆EBV-DNA、血清CYFRA21-1、TSGF在鼻咽癌诊断、近期疗效判断及监测复发和转移等方面的临床意义.方法:分别采用荧光定量PCR、电化学发光免疫测定法及比色法检测46例鼻咽癌患者及15例健康对照的血浆EBV-DNA、血清CYFRA21-1及TSGF.结果:初诊患者血浆EBV-DNA、血清CYFRA21-1、TSGF检测的阳性率及浓度均明显高于健康对照组(P＜0.05),其中血浆EBV-DNA检测的敏感性最高95.2%(20/21).治疗后有肿瘤残余的患者血浆EBV-DNA及血清TSGF浓度明显高于肿瘤完全消退的患者(P＜0.05).局部复发和远处转移的患者三种指标阳性率及浓度均明显高于持续缓解患者(P＜0.05).结论:血浆EBV-DNA、血清CYFRA21-1及TSGF的检测对鼻咽癌的诊断、近期疗效判断及监测局部复发或远处转移都有重要价值,其中血浆EBV-DNA检测的作用更佳.     

血浆EBV-DNA定量检测对复发/转移鼻咽癌患者的意义

[目的]探讨EBV-DNA在复发/转移鼻咽癌患者中表达特点及其临床意义.[方法]56例行EBV-DNA检测的复发/转移鼻咽癌患者56例,其中有25例患者为单纯局部复发,27例患者为单纯远处转移,4例患者为局部复发伴远处转移,另收集100例目前无复发证据的已治鼻咽癌患者作为对照.荧光定量PCR检测血浆EBV-DNA的表达水平.[结果]56例复发/转移鼻咽癌患者中血浆EBV-DNA阳性检出率为57.1％(32/56),阳性患者中EBV-DNA中位浓度为3.845×103copies/ml.单纯局部复发患者中,EBV-DNA阳性检出率为56.0％(14/25),单纯远处转移的患者中,EBV-DNA阳性检出率为51.8％(14/27),局部复发伴转移的患者中,EBV-DNA阳性率为100.00％(4/4).100例无复发证据的已治鼻咽癌患者中,EBV-DNA阳性检出率为4.0％(4/100),阳性患者中EBV-DNA中位浓度为1.79× 102copies/ml.[结论]在复发/转移的鼻咽癌患者中EBV-DNA有较高的检出率,且其表达水平较高,特异性高,对于EBV-DNA表达阳性且持续升高达≥1.0× 103copies/ml的已治鼻咽癌患者,应高度警惕复发及转移.     

Detecting plasma Epstein-Barr virus DNA to diagnose postradiation nasopharyngeal skull base lesions in nasopharyngeal carcinoma patients: a prospective study

The diagnosis of postradiation nasopharyngeal skull base lesions in petients with nasopharyngeal carcinoma(NPC) is still a tough problem in clinical practice.An early and accurate diagnosis is important for subsequent management.We prospectively evaluated the diagnostic value of plasma Epstein-Barr virus(EBV) DNA in detecting postradiation nasopharyngeal skull base lesions in NPC patients.From July 2006 to September 2010,90 patients with postradiation NPC(34 women and 56 men;median age:42 years) met the selection criteria and were recruited in this study.All postradiation nasopharyngeal skull base lesions were found in the latest magnetic resonance imaging(MRI) examinations before endoscopic surgery,and the nasopharyngeal cavity was normal under flexible nasopharyngoscopy.Plasma EBV DNA detection was performed within 2 weeks before endoscopic surgery.A total of 90 endoscopic operations were successfully performed without any postoperative complications.Recurrences confirmed by postoperative pathology were found in 30 patients.The specificity,positive and negative predictive values of plasma EBV DNA detection were better than those of MRI.In addition,combining plasma EBV DNA detection with MRI improved the specificity and positive predictive values of MRI.Plasma EBV DNA detection followed by MRI would help to diagnose recurrence whereas MRI was unable.These results indicate that plasma EBV DNA is an effective and feasible biomarker for detecting postradiation nasopharyngeal skull base lesions in NPC patients.     

Early detection of nasopharyngeal carcinoma by plasma Epstein‐Barr virus DNA analysis in a surveillance program

BACKGROUND:

Nasopharyngeal carcinoma (NPC) is prevalent in Southeast Asia. Over the last decade, plasma Epstein‐Barr virus (EBV) DNA has been developed as a tumor marker for NPC. In this study, the authors investigated whether plasma EBV DNA analysis is useful for NPC surveillance.

METHODS:

In total, 1318 volunteers ages 40 to 60 years were prospectively recruited. Plasma EBV DNA and serology for viral capsid antigen immunoglobulin A (IgA) were measured. Participants who had detectable plasma EBV DNA or positive IgA serology underwent nasal endoscopic examination and a follow‐up plasma EBV DNA analysis in approximately 2 weeks. All participants were followed for 2 years to record the development of NPC.

RESULTS:

Three individuals with NPC were identified at enrolment. All of them were positive for EBV DNA and remained positive in follow‐up analysis. Only 1 of those patients was positive for EBV serology. In 1 patient who had NPC with a small tumor confined to the mucosa, the tumor was not detectable on endoscopic examination. Because of a 2‐fold increase in plasma EBV DNA on the follow‐up analysis, that patient underwent magnetic resonance imaging, which revealed the tumor. Among the participants who did not have NPC but had initially positive plasma EBV DNA results, approximately 66% had negative EBV DNA results after a median of 2 weeks.

CONCLUSIONS:

Plasma EBV DNA analysis proved useful for detecting early NPC in individuals without a clinical suspicion of NPC. Repeating the test in those who had initially positive results differentiated those with NPC from those who had false‐positive results. Cancer 2013. © 2013 American Cancer Society.     

Disparity of sensitivities in detection of radiation-na?ve and postirradiation recurrent nasopharyngeal carcinoma of the undifferentiated type by quantitative analysis of circulating Epstein-Barr virus DNA1,2.

PURPOSE: The purpose of this research was to compare the sensitivities of plasma EBV DNA in detection of postirradiation locally recurrent nasopharyngeal carcinoma (NPC), postirradiation distant metastatic NPC, and radiation-na?ve NPC. EXPERIMENTAL DESIGN: Twenty-four patients with postirradiation local recurrence of NPC were assessed for plasma EBV DNA levels by a real-time quantitative PCR system. The results were compared with those of a cohort of 140 patients with newly diagnosed NPC and with those of 25 patients with distant metastatic relapse. EBV-encoded RNA positivity was also assessed in locally recurrent tumors and newly diagnosed tumors with undetectable plasma EBV DNA levels. RESULTS: Postirradiation locally recurrent tumors were associated with a significantly lower rate of detectable plasma EBV DNA compared with radiation-na?ve tumors of comparable stage [stage I-II tumors: 5 of 12 (42%) versus 47 of 51 (92%), P = 0.0002; stage III-IV tumors: 10 of 12 (83%) versus 88 of 89 (99%), P = 0.01; Fisher's exact test], and compared with distant metastatic recurrences [15 of 24 (63%) versus 24 of 25 (96%), P < 0.02; Fisher's exact test]. The median EBV DNA level in patients with detectable EBV DNA was also significantly lower in locally recurrent tumors than in radiation-na?ve tumors. All of the tissue samples of tumors associated with undetectable EBV DNA levels, where available, were EBV-encoded RNA positive. CONCLUSIONS: The sensitivity of EBV DNA in the detection of tumors regrowing from an irradiated site is much lower than that from a radiation-na?ve site. Although plasma EBV DNA is very effective in detecting distant metastatic relapse of NPC, it cannot be relied on as the sole surveillance tool for detection of local relapse.     

Plasma Epstein-Barr virus DNA level strongly predicts survival in metastatic/recurrent nasopharyngeal carcinoma treated with palliative chemotherapy

BACKGROUND:

Plasma Epstein‐Barr virus (EBV) DNA is widely used in screening, monitoring, and prediction of relapse in nonmetastatic nasopharyngeal carcinoma (NPC). However, data regarding utility of plasma EBV DNA in metastatic NPC are rare. The current study was to test the prognostic implication of plasma EBV DNA level in metastatic/recurrent NPC patients treated with palliative chemotherapy.

METHODS:

Plasma EBV DNA level was measured at baseline and thereafter at the start of each treatment cycle in 127 histologically proven metastatic/recurrent NPC patients treated with palliative chemotherapy. Correlations of pre‐treatment and post‐treatment plasma EBV DNA levels to survival and response were analyzed.

RESULTS:

Patients with a low pre‐treatment plasma EBV DNA level ( CONCLUSIONS: Plasma EBV DNA is of predictive value for prognosis in metastatic/recurrent NPC patients undergoing palliative chemotherapy. The pre‐treatment plasma EBV DNA level as well as the early decrease of plasma EBV DNA after chemotherapy enabled easy and early discrimination between patients who will and those who will not benefit from continued treatment. Cancer 2011. © 2011 American Cancer Society.     

Comparison of plasma Epstein-Barr virus (EBV) DNA levels and serum EBV immunoglobulin A/virus capsid antigen antibody titers in patients with nasopharyngeal carcinoma

BACKGROUND: Serologic measurement of antibodies to Epstein-Barr virus (EBV) immunoglobulin A/viral capsid antigen (IgA/VCA) and early antigen (IgA/EA) has been used widely to screen for nasopharyngeal carcinoma (NPC) in China. Recently, it was found that plasma EBV DNA concentration is an indicator for the staging and prognosis of patients with NPC. To determine whether there is a correlation between plasma EBV DNA levels and serum levels of IgA/VCA, the authors measured both in patients with NPC and in a control group. METHODS: Real-time polymerase chain reaction was used for quantitative analysis of plasma EBV DNA concentration, and enzyme-linked immunoadsorbent assay was used to measure EBV VCA/IgA in patients with primary NPC (n = 120 patients), locally recurrent NPC (n = 8 patients), and distant metastatic NPC (n = 21 patients) among 76 patients with NPC after the completion of radiotherapy, in 60 patients with NPC in clinical remission, in 38 patients with non-NPC tumors, and in 47 control individuals. RESULTS: The median plasma EBV DNA levels were 6200 copies/mL, 9200 copies/mL, and 2050 copies/mL in patients with primary, locally recurrent, and distant metastatic NPC, respectively, but declined to 0 copies/mL in patients with clinically remissive NPC, in patients who completed radiotherapy, in patients with non-NPC tumors, and in the control group. In contrast, EBV VCA/IgA titers and detection rates remained high in all NPC groups. Plasma EBV DNA levels were significantly higher in patients who had serum VCA/IgA titers > or = 1:640 (median, 83,450 copies/mL) compared with the levels in patients who had titers < or = 1:320 (median, 17,200 copies/mL). Patients with NPC who had advanced TNM stage (Stages III and IV; median, 8530 copies/mL) and T classification (T3 and T4 tumors; median, 8530 copies/mL) had significantly higher plasma EBV DNA levels compared with patients who had early TNM stage (Stages I and II; median, 930 copies/mL) and T classification (T1 and T2 tumors; median, 3700 copies). Patients who had advanced TNM stage NPC had significantly higher mean VCA/IgA titers (1:424) compared with patients who had early TNM stage NPC (1:246), but there was no correlation between IgA/VCA titer and T or N classification of NPC. CONCLUSIONS: The results suggest that plasma EBV DNA detection is a more sensitive and specific marker than the serum IgA/VCA titer for the diagnosis and monitoring of patients with NPC. These findings provide convincing evidence for the use of plasma EBV DNA measurements for the early diagnosis and staging of NPC as well as for monitoring recurrence and metastasis of this tumor.     

Comparison of the prognostic impact of serum anti-EBV antibody and plasma EBV DNA assays in nasopharyngeal carcinoma

PURPOSE: Nasopharyngeal carcinoma (NPC) has been proven as an Epstein-Barr virus (EBV)-associated cancer. Serum anti-EBV antibodies and plasma EBV DNA have been investigated as surrogate markers for NPC. A comparison of the prognostic impacts of both assays has never been reported. METHODS AND MATERIALS: Paired serum and plasma samples from 114 previously untreated NPC patients were collected and subjected to an immunofluorescence assay for immunoglobulin (Ig)A and IgG antibodies against the viral capsid antigen (VCA) and a real-time quantitative polymerase chain reaction assay for EBV DNA measurement. The effects of both assays on patient prognosis were thoroughly investigated. RESULTS: Relapsed patients had significantly higher pretreatment EBV DNA concentration than patients without relapse (p = 0.0006). No associations of VCA-IgA (p = 0.9669) or VCA-IgG (p = 0.6125) were observed between patients with and without relapse. The 4-year overall survival (60.3% vs. 93.1%, p < 0.0001) and relapse-free survival rates (54.4% vs. 77.9%, p = 0.0009) were significantly lower in patients with higher pretreatment EBV DNA load than in those with lower EBV DNA load. Patients with persistently detectable EBV DNA after treatment had significantly worse 4-year overall (30.8% vs. 84.6%, p < 0.0001) and relapse-free survival rates (15.4% vs. 74.0%, p < 0.0001) than those with undetectable EBV DNA. The VCA-IgA and VCA-IgG titer could not predict survivals (all p > 0.1). Cox multivariate analyses also showed the same results. CONCLUSION: Plasma EBV DNA is superior to serum EBV VCA antibodies in prognostic predictions for NPC.     

Plasma Epstein-Barr virus DNA and residual disease after radiotherapy for undifferentiated nasopharyngeal carcinoma

BACKGROUND: Epstein-Barr virus (EBV) DNA can be detected and quantified in the plasma of patients with EBV-related tumors, such as nasopharyngeal carcinoma (NPC). Although NPC at early stages can be cured by radical radiotherapy, there is a high recurrence rate in patients with advanced NPC. The pretreatment level of circulating EBV DNA is a prognostic factor for NPC, but the prognostic value of post-treatment EBV DNA has not been studied. We designed a prospective study in Hong Kong, China, to investigate the value of plasma EBV DNA as a prognostic factor for NPC. METHODS: One hundred seventy NPC patients, without metastatic disease at presentation, were treated with a uniform radiotherapy protocol. Circulating EBV DNA was measured by real-time quantitative polymerase chain reaction before treatment and 6-8 weeks after radiotherapy was completed. Risk ratios (RRs) were determined with a Cox regression model, and associations of various factors with progression-free and overall survival and recurrence rates were determined with a stepwise Cox proportional hazards model. All statistical tests were two-sided. RESULTS: Ninety-nine percent of patients achieved complete clinical remission. Levels of post-treatment EBV DNA dominated the effect of levels of pretreatment EBV DNA for progression-free survival. The RR for NPC recurrence was 11.9 (95% confidence interval [CI] = 5.53 to 25.43) for patients with higher post-treatment EBV DNA and 2.5 (95% CI = 1.14 to 5.70) for patients with higher pretreatment EBV DNA. Higher levels of post-treatment EBV DNA were statistically significantly associated with overall survival (P<.001; RR for NPC recurrence = 8.6, 95% CI = 3.69 to 19.97). The positive and negative predictive values for NPC recurrence for a higher level of post-treatment EBV DNA were 87% (95% CI = 58% to 98%) and 83% (95% CI = 76% to 89%), respectively. CONCLUSION: Levels of post-treatment plasma EBV DNA in patients with NPC appear to strongly predict progression-free and overall survival and to accurately reflect the post-treatment residual tumor load.