Prognostic value of plasma Epstein–Barr virus DNA level during posttreatment follow-up in the patients with nasopharyngeal carcinoma having undergone intensity-modulated radiotherapy

Background: The value of Epstein–Barr virus (EBV) DNA assay during posttreatment follow-up of the patients with nasopharyngeal carcinoma (NPC) presenting with different pretreatment plasma EBV DNA levels remains unclear. In the present study, we aimed to evaluate the prognostic value of plasma EBV DNA assay during posttreatment follow-up in the patients with NPC who have undergone intensity-modulated radiotherapy. Methods: The medical records of 385 NPC patients treated with intensity-modulated radiotherapy between Novem-ber 2009 and February 2012 were reviewed. All patients underwent plasma EBV DNA assays before treatment, within 3 months after treatment, and then every 3–12 months during posttreatment follow-up period. The recurrence rates for patients with different pretreatment and posttreatment follow-up plasma EBV DNA levels were analyzed. Results: Of the 385 patients, 267 (69.4％) had detectable pretreatment plasma EBV DNA (> 0 copy/mL) and 93 (24.2％) had detectable posttreatment EBV DNA during a median follow-up of 52.8 months (range 9.3–73.8 months). Detectable EBV DNA during posttreatment follow-up was found in 14.4％ (17/118) and 28.5％ (76/267) of patients with undetectable and detectable pretreatment EBV DNA, respectively, and was significantly associated with tumor recurrence in both patient groups. EBV DNA was detectable in 12.8％ (40/313) of patients who remained disease-free, 56.4％ (22/39) of patients with locoregional recurrence alone, and 93.9％ (31/33) of patients with distant metastasis as the first recurrence event (P < 0.001); 6.5％ (19/292) of patients with undetectable EBV DNA and 57.0％ (53/93) of patient with detectable EBV DNA during posttreatment follow-up experienced tumor recurrence. Compared with other cut-off values, the cut-off value of 0 copy/mL for EBV DNA during posttreatment follow-up had the highest area under the ROC curve (AUC) value (0.804, 95％ confidence interval 0.741–0.868) for predicting tumor recurrence (sensi-tivity, specificity, and accuracy: 73.6％, 87.2％, and 84.7％, respectively).Conclusion: Plasma EBV DNA level during posttreatment follow-up is a good marker for predicting distant metasta-sis but not locoregional recurrence in the patients with NPC irrespective of the pretreatment EBV DNA levels.     

Laboratory markers of tumor burden in nasopharyngeal carcinoma: a comparison of viral load and serologic tests for Epstein-Barr virus

Epstein-Barr virus (EBV) is present within the tumor cells of most cases of nasopharyngeal carcinoma (NPC). Recent studies suggest that tumor burden is proportional to the level of EBV DNA in blood and that rapid blood testing can be used to guide therapeutic intervention. The relative utility of viral load vs. serology has been insufficiently studied. In our study, EBV viral load was measured by quantitative PCR using either real-time or end-point detection systems in serum samples from 124 NPC patients (93 pretreatment, 13 relapsed, 18 in remission) and 40 controls. Serologic titers against EBV early antigen were measured in the same serum samples. EBV DNA was detectable in 64 of 93 untreated NPC patients (69%; mean viral load 11,211 copies/ml), 11 of 13 relapsed NPC patients (85%; mean 53,039 copies/ml) and 0 of 18 remission patients. EBV DNA was detectable in only 1 of 40 non-NPC controls (3%). In 34 instances where paired plasma and serum samples were available for testing, both were effective sample types, and there was no significant difference between end-point and real-time methods for measuring viral load. Early antigen (EA) IgA and IgG titers were elevated in most NPC patients regardless of whether their disease was active or in remission. EBV viral load was more informative than was EA serology for distinguishing remission from relapsed disease. EBV DNA measurement appears to be a noninvasive way to monitor tumor burden after therapy.     

Molecular prognostication of nasopharyngeal carcinoma by quantitative analysis of circulating Epstein-Barr virus DNA

We investigated the prognostic implication of pretreatment plasma/serum EBV DNA concentration, as measured by real-time quantitative PCR, in nasopharyngeal carcinoma (NPC). In 91 prospectively recruited NPC patients, those with recurrence or metastasis within the first year after treatment had a higher median plasma EBV DNA concentration than those without events (41,756 copies/ml versus 5,807 copies/ml; P < 0.001, Mann-Whitney rank-sum test). In multivariate logistic regression analysis, plasma EBV DNA was an independent prognostic indicator for early clinical events [relative risk = 3.8 (95% confidence interval, 1.6-9.2 for each 10-fold increase in plasma EBV DNA concentration; P = 0.003)]. In a second cohort of 139 NPC patients followed-up for a median period of 2,027 days (interquartile range, 597-2,335 days), serum EBV DNA was found to be a significant variable associated with NPC-related death in multivariate Cox's regression analysis [relative risk = 1.6 (95% confidence interval, 1.1-2.1 for each 10-fold increase in serum EBV DNA concentration; P = 0.007)]. The quantitation of circulating EBV DNA may thus allow improved prognostication of NPC.     

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.     

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。     

Pretherapy quantitative measurement of circulating Epstein-Barr virus DNA is predictive of posttherapy distant failure in patients with early-stage nasopharyngeal carcinoma of undifferentiated type

BACKGROUND: Patients with International Union Against Cancer (UICC) Stage I-II nasopharyngeal carcinoma (NPC) appear to have a relatively favorable prognosis and generally are excluded from trials of combined modality treatment. More recently, plasma/serum cell-free Epstein-Barr virus (EBV) DNA has been shown to be measurable in the majority of NPC patients at the time of diagnosis, and appears to have prognostic significance. However, within Stage I-II disease, in which failure events are infrequent, the prognostic impact of the pretreatment EBV DNA level has not been addressed to our knowledge. This issue has management implications because different therapeutic strategies currently are employed for patients with good-risk and those with poor-risk NPC. METHODS: A cohort of 90 patients with UICC Stage I-II NPC (World Health Organization Grade 2/3 histology) had their pretherapy plasma/serum EBV DNA levels determined by a quantitative polymerase chain reaction assay and correlated with the probability of posttherapy failure. All patients received radiation therapy only, except for three patients who also received concurrent chemotherapy. Kaplan-Meier plots of the probability of locoregional failure, distant failure, and cancer-specific survival were compared with reference to clinical stage and EBV DNA levels. RESULTS: With a median follow-up time of 45 months, 12 patients and 7 patients, respectively, had developed locoregional and distant failures, including 2 patients with both local and distant failures. Patients with distant failure had significantly higher pretherapy EBV DNA levels than those without failure (a median of 13,219 copies/mL [interquatile-range, 274,635 copies/mL] vs. a median of 423 copies/mL [interquatile-range, 2753 copies/mL]). The probability of distant failure was significantly higher in patients with high (>4000 copies/mL plasma) compared with low EBV DNA levels (P=0.0001, log-rank test) and for Stage IIB disease compared with Stage I and Stage IIA disease combined (P=0.0149, log-rank test), but was not significantly different between patients with Stage II and those with Stage I disease. The risks of locoregional failure were not significantly different between patients with high and those with low EBV DNA levels, and also was not significantly different between clinical substages. Approximately 35% of patients with Stage IIB disease were in the at-risk group for distant failure, as identified by high EBV DNA levels. CONCLUSIONS: Within a group of patients with UICC Stage I-II NPC, the pretherapy plasma EBV DNA level was found to identify a poor-risk group with a probability of distant failure similar to that of patients with advanced stage disease. This group of patients may warrant management considerations currently applicable only to cases of Stage III-IV disease. The prognostic significance of designating Stage IIB disease as per the 1997 UICC staging was confirmed, although the pretherapy EBV DNA level appears to be a more powerful prognostic discriminator in patients with early-stage NPC.     

血浆 EB病毒游离 DNA检测对监测鼻咽癌患者预后的意义

背景与目的:有报道 , 测定血浆中的 EB病毒游离 DNA( EBV-DNA)的拷贝数可作为诊断及监测鼻咽癌患者病情变化的手段之一.本研究旨在评价血浆 EBV-DNA检测在鼻咽癌患者预后监测上的价值, 并进一步与 VCA/IgA、 EA/IgA进行比较.方法:比较鼻咽癌放疗后 30例远处转移患者、 22例局部复发患者、 24例无 瘤生存者血浆中 EBV-DNA、 VCA/IgA、 EA/IgA水平.分别应用荧光定量 PCR方法检测血浆 EBV-DNA水平,免疫酶法检测 VCA/IgA、 EA/IgA;前瞻性观察 20例初诊鼻咽癌患者放疗前、放疗剂量达 40 Gy时及放疗结束时上述指标的变化. 结果:放疗后各组不同预后患者的血浆 EBV-DNA含量的中位数有显著性差异, 远处转移组为 135 100 copies/ml(四分线区域 5 525～ 1 003 750 copies/ml) >局部复发组的 20 500(四分线区域 0～ 58 500 copies/ml) > 无瘤生存组的 0 copy/ml(四分线区域 0～ 0 copy/ml), P均 < 0.05. 远处转移组的血浆 EBV-DNA水平高者较多, 当阳性标准为 1 000 000 copies/ml时,诊断远处转移组的敏感性为 27.3%,而诊断局部复发组的敏感性为 0.0%,特异性均为 100.0%.在初诊患者放疗前、放疗剂量达 40 Gy时及放疗结束时, EBV-DNA水平逐渐降低,平均含量分别为 32 050 copies/ml(四分线区域 3 880～ 317 750 copies/ml)、 0 copy/ml(四分线区域 0～ 14 375 copies/ml)、 0 copy/ml(四分线区域 0～ 2 940 copies/ml), P均 < 0.05, 而 VCA/IgA、 EA/IgA的水平未见明显变化. 结论: 血浆 EBV-DNA检测可用于监测鼻咽癌患者预后,其价值明显优于 VCA/IgA、 EA/IgA.     

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。     

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.     

Significance of cell-free epstein-barr virus DNA in monitoring prognosis of nasopharyngeal carcinoma

Objective It has been reported that cell-free Epstein-Barr virus (EBV-DNA) in plasma was useful in diagnosing and monitoring nasopharyngeal carcinoma (NPC). The current study was designed to evaluate the significance of EBV-DNA in monitoring the prognosis of nasopharyngeal carcinoma and comparing its significance with that of plasma VCA/lgA and EA/lgA levels. Methods E8V -DNA, VCA/lgA, and EA/lgA levels in plasma were determined in NPC patients with different prognosis after radiotherapy, including 30 distant metastatic patients, 22 local recurrence patients and 24 individuals with remission who had been followed-up for more than 2 years after treatment. EBV-DNA was determined using a real-time quantitative PCR system, and levels of VCA/lgA and EA/lgA were measured using standard immunofluorescence. In a cohort study, the indexes were determined after different radiation periods for the 20 new cases of nasopharyngeal carcinoma. Results The median plasma EBV-DNA concentration was 135,100 copies/ ml (interquartile range: 5,525-1,003 750) in metastatic group, 20,500 copies/ ml (interquartile range: 0 -58,500) in the local recurrence group and 0 copies/ml (interquartile range: 0-0) in the continuous remission group (P< 0.05). The levels of VCA/lgA and EA/lgA showed no significant differences among the different groups. The high level of EBV-DNA concentration in the metastatic group was more than that in the local recurrence group. A level of 1,000,000 copies/ml of EBV DNA was an indication of distant metastasis of the NPC patients with a sensitivity of 27.3%. However, the sensitivity was 0 in the local recurrence group. For the 20 new patients, EBV -DNA concentration gradually decreased during the radiation period. Before radiation there were 32,050 copies/ml (interquartile range: 3,880-317,750), 0 copies/ml (interquartile range: 0-14 375) after a 40 Gy radiation dose and 0 copies/ml (interquartile range: 0-2940) after the radiation was finished (P< 0.05). However, the levels of VCA/lgA and EA/lgA showed no significant difference. Conclusion Determination of plasma cell -free EBV -DNA level is more valuable than evaluation of VCA/lgA and EA/lgA for monitoring the prognosis of NPC patients.     

鼻咽癌患者血浆EBV-DNA检测的临床价值

目的 EB病毒与鼻咽癌的发生发展明确相关,多个研究显示血浆EBV-DNA对于鼻咽癌的诊断分期及预后判断有重要意义,因此对我院患者进行了血浆EBV-DNA的检测并分析其临床价值。方法 2013—2016年连续性鼻咽癌患者471例,分析其治疗前EBV-DNA水平与分期、肿瘤负荷的相关性,并对治疗前、治疗末EBV-DNA进行生存相关分析。结果 患者治疗前血浆EBV-DNA中位数137 copies/ml (0~494000),与T分期、N分期、M分期、总的临床分期、肿瘤负荷均有明显统计学相关性。生存分析显示治疗前血浆EBV-DNA拷贝数≤1300组比>1300组的患者有更好OS (P=0.007)、PFS (P=0.011)、DMFS (P=0.003)。治疗末血浆EBV-DNA不可检测到的患者有更好OS (P=0.016)、PFS (P=0.000)、DMFS (P=0.000)。Cox多因素分析T分期、治疗末是否可检测到EBV-DNA为OS (P=0.030、0.012)的预后因素,N分期(P=0.037、0.017)、放疗末是否可检测到EBV-DNA (P=0.006、0.001)为PFS及DMFS的预后因素。结论 鼻咽癌患者治疗前血浆EBV-DNA水平与分期及肿瘤负荷有明显相关性,治疗前EBV-DNA水平更高的患者可能治疗后的预后更差。治疗末血浆EBV-DNA是否可检测到对于OS、PFS、DMFS有较好的预测价值。     

Long‐term survival analysis of nasopharyngeal carcinoma by plasma Epstein‐Barr virus DNA levels

BACKGROUND: The objective of this study was to confirm the relation between plasma Epstein‐Barr virus (EBV) DNA (pEBV DNA) load and treatment outcomes after long‐term follow‐up in patients with nasopharyngeal carcinoma (NPC). METHODS: In total, 210 patients with NPC were enrolled, including 99 previously reported patients and 111 new patients. They prospectively received treatment with induction chemotherapy plus radiotherapy and were followed for at least 6 years. In these patients, pEBV DNA levels were measured before treatment and 1 week after treatment. The plasma viral load was correlated with treatment outcomes in the group of new patients and in the entire group. RESULTS : By using previously defined pEBV DNA cutoff values (1500 copies/mL pretreatment and 0 copies/mL post‐treatment), there was a significant correlation between the pEBV DNA value and relapse‐free survival, overall survival, and subsequent relapse rates in the new, independent patient cohort. Outcome analyses for the entire group revealed a higher relapse rate (45.6% vs 21.5% [P = .0037] or 76.7% vs 26.1% [P < .0001]), a worse relapse‐free survival rate (56.5% vs 79.3% [P < .0001] or 23.3% vs 75.6% [P < .0001]), and poorer overall survival (59.2% vs 86% [P = .0003] or 33.3% vs 79.4% [P < .0001]) in patients who had high pretreatment or persistently detectable post‐treatment pEBV DNA levels, respectively, versus their respective counterparts. Multivariate Cox analysis also confirmed these results. CONCLUSIONS : In this expanded study, the prognostic significance of pEBV DNA was confirmed using predefined cutoff values in an independent patient group, and pEBV DNA was identified as an independent prognostic marker for NPC. Cancer 2013. © 2012 American Cancer Society.     

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.     

Quantitative analysis of cell-free Epstein-Barr virus DNA in plasma of patients with nasopharyngeal carcinoma

Using real-time quantitative PCR, cell-free EBV DNA was detectable in the plasma of 96% (55 of 57) of nasopharyngeal carcinoma (NPC) patients (median concentration, 21058 copies/ml) and 7% (3 of 43) of controls (median concentration, 0 copies/ml). Advanced-stage NPC patients had higher plasma EBV DNA levels than those with early-stage disease. At 1 month after completion of radiotherapy, plasma EBV DNA was undetectable in 7 of 15 subjects (47%) but remained high in the remaining 8 subjects (53%). Clinical examination revealed that all of the former seven subjects had complete tumor regression, whereas six of the eight latter subjects exhibited evidence of disease persistence or had developed distant metastases. These results suggest that quantitative analysis of plasma EBV DNA may be a useful clinical and research tool in the screening and monitoring of NPC patients.     

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.     

A comparison study of different PCR assays in measuring circulating plasma epstein-barr virus DNA levels in patients with nasopharyngeal carcinoma.

PURPOSE: To compare the performance of three PCR assays in measuring circulating Epstein-Barr virus (EBV). DNA levels in nasopharyngeal carcinoma patients and to confirm its prognostic significance. EXPERIMENTAL DESIGN: Plasma from 58 newly diagnosed nasopharyngeal carcinoma patients were collected before, during, and every 3 to 6 months after radiotherapy. EBV DNA levels were determined by real-time quantitative PCR using primer/probe sets for polymerase-1 (Pol-1), latent membrane protein 2 (Lmp2), and BamHI-W. Pretreatment levels from the three assays were correlated with each other and serial measurements from the Pol-1 assay were correlated with clinical variables. RESULTS: Pol-1 was more accurate than BamHI-W in predicting EBV DNA concentrations in cell lines. Of the three assays, BamHI-W yielded the highest concentrations followed by Pol-1 in plasmas (n = 23). The correlation coefficient was 0.99 (P < 0.0001) for Pol-1 and Lmp2, 0.66 (P < 0.0001) for Pol-1 and BamHI-W, and 0.55 (P < 0.0001) for BamHI-W and Lmp2. Elevated pretreatment DNA levels as detected by Pol-1 were correlated with advanced nodal stage (P = 0.04) and overall stage (P = 0.028). There was no correlation between pretreatment EBV DNA levels and freedom-from-relapse or overall survival; however, there was a significant correlation between posttreatment levels and these variables. The 2-year freedom-from-relapse and overall survival rates were 92% and 94% for patients with undetectable, and 37% and 55% for those with detectable, posttreatment levels (P < 0.0001 and P < 0.002). CONCLUSIONS: The three PCR assays yielded similar results in detecting EBV DNA in plasmas. The Pol-1-detected posttreatment EBV DNA level was the strongest predictor for treatment outcomes.     

Prognostic values of the integrated model incorporating the volume of metastatic regional cervical lymph node and pretreatment serum Epstein–Barr virus DNA copy number in predicting distant metastasis in patients with N1 nasopharyngeal carcinoma

Background: According to the 7th edition of the American Joint Committee on Cancer (AJCC) staging system, over 50% of patients with nasopharyngeal carcinoma (NPC) have N1 disease at initial diagnosis. However, patients with N1 NPC are relatively under-researched, and the metastasis risk of this group is not well-stratified. This study aimed to evaluate the prognostic values of gross tumor volume of metastatic regional lymph node (GTVnd) and pretreatment serum copy number of Epstein–Barr virus (EBV) DNA in predicting distant metastasis of patients with N1 NPC, and to develop an integrated prognostic model that incorporates GTVnd and EBV DNA copy number for this group of patients. Methods: The medical records of 787 newly diagnosed patients with nonmetastatic, histologically proven N1 NPC who were treated at Sun Yat-sen University Cancer Center between November 2009 and February 2012 were ana-lyzed. Computed tomography-derived GTVnd was measured using the summation-of-area technique. Blood sam-ples were collected before treatment to quantify plasma EBV DNA. The receiver operating characteristic (ROC) curve analysis was used to evaluate the cut-off point for GTVnd, and the area under the ROC curve was used to assess the predicted validity of GTVnd. The survival rates were assessed by Kaplan–Meier analysis, and the survival curves were compared using a log-rank test. Multivariate analysis was conducted using the Cox proportional hazard regression model. Results: The 5-year distant metastasis-free survival (DMFS) rates for patients with GTVnd > 18.9 vs. ≤ 18.9 mL were 82.2% vs. 93.2% (P < 0.001), and for patients with EBV DNA copy number > 4000 vs. ≤ 4000 copies/mL were 83.5% vs. 93.9% (P < 0.001). After adjusting for GTVnd, EBV DNA copy number, and T category in the Cox regression model, both GTVnd > 18.9 mL and EBV DNA copy number > 4000 copies/mL were significantly associated with poor prognosis(both P < 0.05). According to combination of GTVnd and EBV DNA copy number, all patients were divided into low-, moderate-, and high-risk groups, with the 5-year DMFS rates of 96.1, 87.4, and 73.8%, respectively (P < 0.001). Multi-variate analysis confirmed the prognostic value of this model for distant metastatic risk stratification (hazard ratio [HR], 4.17; 95% confidence interval [CI] 2.34–7.59; P < 0.001). Conclusions: GTVnd and serum EBV DNA copy number are independent prognostic factors for predicting distant metastasis in NPC patients with N1 disease. The prognostic model incorporating GTVnd and EBV DNA copy number may improve metastatic risk stratification for this group of patients.     

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.     

Quantitative analysis of the transrenal excretion of circulating EBV DNA in nasopharyngeal carcinoma patients

PURPOSE: The existence of transrenal clearance of circulating cell-free DNA is controversial. In this study, we used NPC as a model to investigate if circulating EBV DNA can be excreted into urine and to quantify the contribution of renal excretion to the clearance of plasma EBV DNA. EXPERIMENTAL DESIGN: Quantitative analysis of urine EBV DNA was done for 74 NPC patients using real-time PCR with two different amplicon sizes. The urine concentration of EBV DNA was expressed as copies per millimole of creatinine (copies/mmol Cr) to minimize the effects of interindividual variations in hydration status. RESULTS: EBV DNA was detectable in the urine of 56% NPC patients using a 59-bp real-time PCR assay. The median urine EBV DNA concentrations measured by the 59- and 76-bp assays were 7,040 and 290 copies/mmol Cr, respectively. Patients with detectable urine EBV DNA had significantly higher plasma concentrations, with a positive correlation between the plasma and urine concentrations of EBV DNA. The fraction of plasma EBV DNA excreted into the urine was 0.0026% of that for creatinine. CONCLUSIONS: We have shown that circulating EBV DNA can be excreted transrenally into urine in NPC patient and the fraction of excretion is negatively associated with the size of the DNA molecules. Because there is a positive correlation between plasma and urine EBV DNA concentration, urine EBV DNA analysis may potentially be applicable as an ultra-noninvasive test for the monitoring and prognostication of NPC patients.     

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。