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.     

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.     

Detection of cell free Epstein-Barr virus DNA in sera from patients with nasopharyngeal carcinoma

BACKGROUND: The detection of tumor-derived DNA within the circulation of patients with malignant disease using polymerase chain reaction (PCR)-based strategies has opened a new avenue for the diagnosis and monitoring of these patients. Because of the universal association of Epstein-Barr virus (EBV) with the nonsquamous type of nasopharyngeal carcinoma (NPC; World Health Organization types II and III), the detection of cell free EBV DNA in sera from patients with NPC may be a valuable tool for monitoring the progress of tumors or to provide advanced warning of tumor recurrence. METHODS: Serum samples were obtained from different patients, and cell free EBV DNA was detected with a conventional PCR approach. A total of 134 patients were sampled, including 36 patients with primary NPC, 28 control patients, 18 patients suffering from locoregional recurrence, 7 patients with distant metastasis, and 45 patients with NPC in clinical remission. A conventional PCR approach employing standard 35-cycle and 50-cycle reactions was used to detect cell free EBV genomes. Results from the two PCR cycles were compared to provide a semiquantitative picture of the relative quantity of EBV genome in each serum sample. RESULTS: The EBV DNA detection rates, i.e., the rates of positive detection, for 35-cycle and 50-cycle PCR analyses, respectively, were 38.9% and 75% for patients with primary NPC, 3.5% and 10.7% for control patients, 27.8% and 88.9% for patients with locoregional disease recurrence, 71.4% and 100% for patients with distant metastasis, and 7.1% and 36.5% for patients with disease in clinical remission. The rates of positive detection among patients with active disease all appeared to be significantly greater compared with the rates among patients with disease in clinical remission. Longitudinal data for six patients with recurrent tumors revealed a close correlation between the relative quantity of circulating cell free EBV genomes and the disease course of these patients. The sensitivity, specificity, positive predictive value, and negative predictive value of the 50-cycle PCR analysis for detecting recurrent disease were 92%, 63.5%, 42.6%, and 96.4%, respectively. CONCLUSIONS: This study demonstrated that, by using a 50-cycle PCR-based approach, high sensitivity and high negative predictive value for detecting recurrent disease can be obtained from the detection of the cell free EBV genome in sera from patients with NPC. The 50-cycle PCR analysis, therefore, may provide a simple, clinically useful adjuvant method for monitoring patients with 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.     

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.     

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.     

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.     

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.     

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.     

Rapid clearance of plasma Epstein-Barr virus DNA after surgical treatment of nasopharyngeal carcinoma.

PURPOSE: Circulating EBV DNA analysis has been shown to be valuable in the detection, prognostication, and monitoring of nasopharyngeal carcinoma (NPC) patients. A previous study has shown that, after radiotherapy, plasma EBV DNA levels of NPC patients would decline exponentially with a median half-life of 3.8 days. We postulate that this decline in plasma EBV DNA reflects the decrease in cancer cell population and, therefore, the rate of decline reflects the radiosensitivity of the tumor. However, this postulation would hold true only if EBV DNA is rapidly eliminated from the circulation. In this study, we determined the in vivo elimination rate of plasma EBV DNA in NPC patients. EXPERIMENTAL DESIGN: We monitored the level of plasma EBV DNA in NPC patients during and after surgical resection of NPC. The half-life of plasma EBV DNA was then calculated by plotting the natural logarithm of EBV DNA concentrations against time. RESULTS: The median half-life of plasma EBV DNA after surgical resection of NPC was 139 min. After a median follow-up of 6.7 days, EBV DNA was undetectable in 8 of 11 patients. One of 8 patients with undectable EBV DNA and all of the patients with detectable EBV DNA developed clinical relapse. CONCLUSIONS: The in vivo elimination of EBV DNA is very rapid after surgical resection of NPC. The failure of complete and rapid elimination of EBV DNA from the circulation predicts disease recurrence.     

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

目的：探讨血浆EB病毒DNA、血清细胞角蛋白19片段（CYFRA21-1）和EB病毒壳抗原IgA（VCA-IgA）三种肿瘤标记物对鼻咽癌诊断、疗效监测和预后判断的临床应用价值。方法：分别采用荧光定量PCR法、电化学发光法和免疫酶法检测62例鼻咽癌患者治疗前、后及62例健康对照者血浆EBV DNA、血清CY-FRA21-1和VCA-IgA含量,并进行对比分析。结果：治疗前血浆EBV DNA、血清CYFRA21-1和VCA-IgA的阳性率明显高于健康对照组（P〈0.01）;治疗后血浆EBV DNA、血清CYFRA21-1和VCA-IgA含量高者,在随访中发现肿瘤残存、复发或远处转移。结论：血浆EBV DNA、血清CYFRA21-1和VCA-IgA的检测对鼻咽癌早期诊断、高危人群筛查、以疗效监测和预后判断有重要临床应用价值,三种肿瘤标记物联合检测有互补作用。     

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。     

Prospective validation of serum CYFRA 21-1, beta-2-microglobulin, and ferritin levels as prognostic markers in patients with nonmetastatic nasopharyngeal carcinoma undergoing radiotherapy

BACKGROUND: Patients with undifferentiated nasopharyngeal carcinoma (NPC) have elevated serum levels of CYFRA 21-1 (CYFRA), ferritin, and beta-2-microglobulin (beta2M) compared with healthy control individuals. The prognostic value of these markers has never been validated prospectively. METHODS: Paired serum samples from 160 patients with newly diagnosed, nonmetastatic, undifferentiated NPC were collected before radiotherapy (RT) and at 4-6 weeks after the completion of RT. Pre-RT and post-RT levels of serum CYFRA, ferritin, and beta2M were analyzed and correlated with overall survival (OS), progression-free survival (PFS), time to locoregional recurrence, (TLR) and time to distant recurrence (TDR). The results of pre-RT and post-RT plasma Epstein-Barr virus (EBV) DNA levels available from a previous study were included in a Cox regression model together with age, tumor (T) classification, and lymph node (N) classification. RESULTS: Sixty percent of patients had International Union Against Cancer Stage III-IV disease. At a median follow-up of 116 weeks (range, 37-239 weeks), 38 patients had disease progression. On multivariate analysis, pre-RT CYFRA and post-RT EBV DNA levels were independent predictors of poor OS, post-RT EBV DNA level and N classification predicted poor PFS and TDR; and only T classification predicted TLR. Patients who had pre-RT CYFRA levels > or = 1.5 U/mL were more likely to die (hazard ratio, 1.18; 95% confidence interval, 1.10-1.26) compared with patients who had pre-RT CYFRA levels < 1.5 U/mL. There were no associations between age, post-RT CYFRA levels and pre-RT or post-RT serum ferritin and beta2M levels, and the survival and recurrence rates on multivariate analysis. CONCLUSIONS: Serum CYFRA levels taken before RT predicted reduced survival in patients with nonmetastatic, undifferentiated NPC who underwent RT.     

Quantitative and temporal correlation between circulating cell-free Epstein-Barr virus DNA and tumor recurrence in nasopharyngeal carcinoma.

Recently, cell-free EBV DNA has been detected in the plasma and serum of patients with nasopharyngeal carcinoma (NPC). We studied the relationship between plasma/serum EBV DNA and tumor recurrence. Using real-time quantitative PCR, the median plasma EBV DNA concentration in 10 patients with tumor recurrence was determined to be 32,350 copies/ml, whereas that in 15 patients in continuous remission for a mean period of 2 years was 0 copy/ml. Longitudinal follow-up of 17 NPC patients revealed 6 individuals with tumor recurrence and 11 patients who remained in remission. Significant elevations in serum EBV DNA, sometimes up to 6 months before detectable clinical deterioration, were observed in the patients who subsequently developed tumor recurrence. Continuously low or undetectable levels of serum EBV DNA were observed in the patients who remained in remission. These results suggest that plasma/serum cell-free EBV DNA may be a valuable tool for the monitoring of NPC patients for the early detection of tumor recurrence.     

Plasma Epstein-Barr virus DNA screening followed by ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography in detecting posttreatment failures of nasopharyngeal carcinoma

BACKGROUND:

The authors investigated the clinical implication of plasma Epstein‐Barr virus (EBV) DNA assay and ¹⁸F‐fluoro‐2‐deoxy‐D‐glucose (¹⁸F‐FDG) positron emission tomography (PET) in the detection of recurrent nasopharyngeal carcinoma (NPC).

METHODS:

Two hundred forty‐five patients with NPC who had previously received treatment and were in a state of remission were monitored prospectively using a plasma EBV DNA assay every 3 to 6 months. ¹⁸F‐FDG PET studies were obtained when abnormal EBV DNA or clinically suggestive signs of recurrence were noted.

RESULTS:

Thirty‐six of 245 patients (14.7%) patients had abnormal EBV DNA tests and underwent PET scans. In the remaining 209 patients, 3658 blood tests were negative. PET scans also were obtained in 5 patients who had undetectable EBV DNA levels but signs that were clinically suggestive of disease recurrence. Subsequent analyses focused on 41 patients who had PET studies. In lesion‐based analyses, the sensitivity, specificity, and accuracy of PET by visual interpretation were 81.8%, 77.1%, and 79.2%, respectively, for all 125 lesions. In patient‐based analyses, the accuracy of PET by visual interpretation was 51.2%. All 36 patients who had detectable plasma levels of EBV DNA had demonstrable NPC recurrences, whereas no recurrences were noted in 5 patients who had undetectable EBV DNA levels but signs that clinically mimicked a recurrence. Compared with annual PET, the annual cost of blood tests every 3 to 6 months per patient saved approximately 77% ～ 88% in expenses.

CONCLUSIONS:

The plasma EBV DNA assay correctly predicted all NPC recurrences, and PET had high capacity to localize potential lesion sites. The authors concluded that applying the strategy of EBV DNA screening followed by PET scanning may guide appropriate further treatment planning in a cost‐effective manner. Cancer 2011;. © 2011 American Cancer Society.     

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.     

Epigenetic markers for noninvasive early detection of nasopharyngeal carcinoma by methylation‐sensitive high resolution melting

Nasopharyngeal carcinoma (NPC) is a human malignancy that is closely associated with Epstein‐Barr Virus (EBV). Early diagnosis of NPC will greatly improve the overall survival. However, current EBV DNA marker detection still lacks the predictive value to perform well in high‐risk populations for early detection of NPC. Since aberrant promoter hypermethylation of tumor suppressor genes (TSGs) is widely considered to be an important epigenetic change in early carcinogenesis, this study identified a panel of methylation markers for early detection of NPC and also assessed the clinical usefulness of these markers with noninvasive plasma specimens instead of biopsies. MS‐HRM assays were carried out to assess the methylation status of a selected panel of four TSGs (RASSF1A, WIF1, DAPK1 and RARβ2) in biopsies, NP brushings and cell‐free plasma from NPC patients. High‐risk and cancer‐free groups were used as controls. DNA methylation panel showed higher sensitivity and specificity than EBV DNA marker in cell‐free plasma from NPC patients at early Stages (I and II) and in addition to the EBV DNA marker, MS‐HRM test for plasma and NP brushing DNA methylation significantly increased the detection rate at all NPC stages as well as local recurrence, using this selected four‐gene panel (p < 0.05). MS‐HRM assay on a selected gene panel has great potential to become a noninvasive and complementary test for NPC early and recurrent detection in combination with the EBV DNA test to increase the sensitivity for NPC detection at an early stage.     

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.     

Kinetics of plasma Epstein-Barr virus DNA during radiation therapy for nasopharyngeal carcinoma

We studied the kinetics of circulating EBV DNA in the plasma of nasopharyngeal carcinoma (NPC) patients. Serial weekly sampling of 10 NPC patients revealed a rapid decline in plasma EBV DNA concentration after treatment. In two subjects, an initial rise in the circulating EBV DNA level was observed immediately after treatment initiation. Plasma EBV DNA levels were monitored daily during the first treatment week in a second cohort of five patients, and the results indicated that an initial rise in plasma EBV DNA concentration could be observed in all subjects during the first treatment week. This observation is consistent with the liberation of EBV DNA after therapy-induced cancer cell death. After this initial rise, plasma EBV DNA concentration was found to decay with a median half-life of 3.8 days (interquartile range, 2.4-4.4 days). Kinetic analysis of circulating tumor-derived DNA during treatment may be a powerful tool for evaluating the in vivo response of NPC and other tumors to antineoplastic treatment and may improve our understanding of the biology of plasma nucleic acids.