Long-term monitoring of dynamic changes in plasma EBV DNA for improved prognosis prediction of nasopharyngeal carcinoma

The efficacy of adjuvant chemotherapy in patients with different midpoint-radiotherapy Epstein-Barr virus DNA plasma loads

OBJECTIVES

This study aimed to evaluate the efficacy of adjuvant chemotherapy (AC) in patients with different midpoint-radiotherapy (mid-RT) Epstein-Barr virus (EBV) DNA plasma loads for locoregionally advanced nasopharyngeal carcinoma (NPC), and to provide decision-making regarding the use of AC.

MATERIALS AND METHODS

A total of 675 consecutive patients diagnosed with stage III-IVa NPC were enrolled in this study. All patients underwent concurrent chemoradiotherapy (CCRT), either with or without induction chemotherapy or AC, or a combination of both. The primary endpoint of this study was progression-free survival (PFS).

RESULTS

Among the 675 enrolled patients, 248 (36.7 %) received AC and 427 (63.3 %) were only observed after CCRT. In total, 149 (22.1 %) patients had detectable mid-RT EBV DNA levels, whereas 526 (77.9 %) had undetectable mid-RT EBV DNA levels. Patients with detectable mid-RT EBV DNA had worse 5-year PFS than those with undetectable mid-RT EBV DNA (74.8 % vs. 81.9 %, P = 0.045). AC group showed significantly better 5-year PFS than observation in patients with detectable mid-RT EBV DNA (82.8 % vs. 66.8 %; HR, 0.480; 95 % CI 0.250-0.919, P = 0.027). Multivariate analyses demonstrated that the treatment methods (AC vs. observation) were independent prognostic factors for PFS (HR, 0.37; 95 % CI 0.19-0.74, P = 0.005). However, in patients with undetectable mid-RT EBV DNA (5-year PFS: HR 0.873, 95 % CI 0.565-1.349, P = 0.52), AC group showed no survival benefit for observation.

CONCLUSION

AC could reduce the risk of disease progression compared to observation in patients with detectable mid-RT EBV DNA. Our findings suggest that AC is effective in patients at a high risk of treatment failure.

The Role of Biomarkers in HPV-Positive Head and Neck Squamous Cell Carcinoma: Towards Precision Medicine

Head and neck cancer (HNC) represents a significant global health challenge, with squamous cell carcinomas (SCCs) accounting for approximately 90% of all HNC cases. These malignancies, collectively referred to as head and neck squamous cell carcinoma (HNSCC), originate from the mucosal epithelium lining the larynx, pharynx, and oral cavity. The primary risk factors associated with HNSCC in economically disadvantaged nations have been chronic alcohol consumption and tobacco use. However, in more affluent countries, the landscape of HNSCC has shifted with the identification of human papillomavirus (HPV) infection, particularly HPV-16, as a major risk factor, especially among nonsmokers. Understanding the evolving risk factors and the distinct biological behaviors of HPV-positive and HPV-negative HNSCC is critical for developing targeted treatment strategies and improving patient outcomes in this complex and diverse group of cancers. Accurate diagnosis of HPV-positive HNSCC is essential for developing a comprehensive model that integrates the molecular characteristics, immune microenvironment, and clinical outcomes. The aim of this comprehensive review was to summarize the current knowledge and advances in the identification of DNA, RNA, and protein biomarkers in bodily fluids and tissues that have introduced new possibilities for minimally or non-invasive cancer diagnosis, monitoring, and assessment of therapeutic responses.

Plasma EBV quantification is associated with the efficacy of immune checkpoint blockade and disease monitoring in patients with primary pulmonary lymphoepithelioma-like carcinoma

Objectives

Primary pulmonary lymphoepithelioma-like carcinoma (PLELC) is a subtype of lung carcinoma associated with the Epstein-Barr virus (EBV). The clinical predictive biomarkers of immune checkpoint blockade (ICB) in PLELC require further investigation.

Methods

We prospectively analysed EBV levels in the blood and immune tumor biomarkers of 31 patients with ICB-treated PLELC. Viral EBNA-1 and BamHI-W DNA fragments in the plasma were quantified in parallel using quantitative polymerase chain reaction.

Results

Progression-free survival (PFS) was significantly longer in EBNA-1 high or BamHI-W high groups. A longer PFS was also observed in patients with both high plasma EBNA-1 or BamHI-W and PD-L1 ≥ 1%. Intriguingly, the tumor mutational burden was inversely correlated with EBNA-1 and BamHI-W. Plasma EBV load was negatively associated with intratumoral CD8+ immune cell infiltration. Dynamic changes in plasma EBV DNA level were in accordance with the changes in tumor volume. An increase in EBV DNA levels during treatment indicated molecular progression that preceded the imaging progression by several months.

Conclusions

Plasma EBV DNA could be a useful and easy-to-use biomarker for predicting the clinical activity of ICB in PLELC and could serve to monitor disease progression earlier than computed tomography imaging.

Radiomics-based nomogram guides adaptive de-intensification in locoregionally advanced nasopharyngeal carcinoma following induction chemotherapy

OBJECTIVES

This study aimed to construct a radiomics-based model for prognosis and benefit prediction of concurrent chemoradiotherapy (CCRT) versus intensity-modulated radiotherapy (IMRT) in locoregionally advanced nasopharyngeal carcinoma (LANPC) following induction chemotherapy (IC).

MATERIALS AND METHODS

A cohort of 718 LANPC patients treated with IC + IMRT or IC + CCRT were retrospectively enrolled and assigned to a training set (n = 503) and a validation set (n = 215). Radiomic features were extracted from pre-IC and post-IC MRI. After feature selection, a delta-radiomics signature was built with LASSO-Cox regression. A nomogram incorporating independent clinical indicators and the delta-radiomics signature was then developed and evaluated for calibration and discrimination. Risk stratification by the nomogram was evaluated with Kaplan-Meier methods.

RESULTS

The delta-radiomics signature, which comprised 19 selected features, was independently associated with prognosis. The nomogram, composed of the delta-radiomics signature, age, T category, N category, treatment, and pre-treatment EBV DNA, showed great calibration and discrimination with an area under the receiver operator characteristic curve of 0.80 (95% CI 0.75-0.85) and 0.75 (95% CI 0.64-0.85) in the training and validation sets. Risk stratification by the nomogram, excluding the treatment factor, resulted in two groups with distinct overall survival. Significantly better outcomes were observed in the high-risk patients with IC + CCRT compared to those with IC + IMRT, while comparable outcomes between IC + IMRT and IC + CCRT were shown for low-risk patients.

CONCLUSION

The radiomics-based nomogram can predict prognosis and survival benefits from concurrent chemotherapy for LANPC following IC. Low-risk patients determined by the nomogram may be potential candidates for omitting concurrent chemotherapy during IMRT.

CLINICAL RELEVANCE STATEMENT

The radiomics-based nomogram was constructed for risk stratification and patient selection. It can help guide clinical decision-making for patients with locoregionally advanced nasopharyngeal carcinoma following induction chemotherapy, and avoid unnecessary toxicity caused by overtreatment.

KEY POINTS

• The benefits from concurrent chemotherapy remained controversial for locoregionally advanced nasopharyngeal carcinoma following induction chemotherapy. • Radiomics-based nomogram achieved prognosis and benefits prediction of concurrent chemotherapy. • Low-risk patients defined by the nomogram were candidates for de-intensification.

Precision Medicine for Nasopharyngeal Cancer-A Review of Current Prognostic Strategies

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV) driven malignancy arising from the nasopharyngeal epithelium. Current treatment strategies depend on the clinical stage of the disease, including the extent of the primary tumour, the extent of nodal disease, and the presence of distant metastasis. With the close association of EBV infection with NPC development, EBV biomarkers have shown promise in predicting treatment outcomes. Among the omic technologies, RNA and miRNA signatures have been widely studied, showing promising results in the research setting to predict treatment response. The transformation of radiology images into measurable features has facilitated the use of radiomics to generate predictive models for better prognostication and treatment selection. Nonetheless, much of this work remains in the research realm, and challenges remain in clinical implementation.

Longitudinal post-radiotherapy plasma Epstein-Barr virus DNA trends inform on optimal risk stratification in endemic nasopharyngeal carcinoma

OBJECTIVES

To characterize longitudinal changes in Epstein-Barr virus (EBV) DNA post-radiotherapy in nasopharyngeal carcinoma (NPC) patients, and investigate whether an early (0-2 weeks) or delayed (8-12 weeks) EBV DNA result better predicts for disease-free survival (DFS).

MATERIALS AND METHODS

Histologically-confirmed NPC patients with ≥1 EBV DNA test quantified using the harmonized BamHI-W polymerase chain reaction-based assay at 0-2 and 8-12 weeks post-radiotherapy were included.

RESULTS

We identified 302 patients with EBV DNA measured at 0-2 weeks post-radiotherapy; of which, 110 (36.4 %) underwent a repeat test at 8-12 weeks post-treatment. Patients harboring a detectable EBV DNA at 0-2 weeks experienced an inferior DFS (adjusted HR1-264 copies 1.72 [95 %CI: 1.05-2.83], P = 0.031; AHR≥265 copies 4.39 [95 %CI: 1.68-11.44], P = 0.002 relative to 0 copies/mL). At 8-12 weeks, we observed substantial shifts in EBV DNA readings from 0 to 2 weeks; 76/110 (69.1 %) and 34/110 (30.9 %) patients at 0-2 weeks versus 90/110 (81.8 %) and 20/110 (18.2 %) at 8-12 weeks recorded undetectable and detectable EBV DNA, respectively. Positive EBV DNA at 8-12 weeks was strongly associated with relapse (73.3 % [11/15] for 1-264; 80.0 % [4/5] for ≥265 subgroups had relapses versus 15.6 % [14/90] for 0 copies/mL). Area under receiver operating curve values for 2-year relapse rates were 0.817 (95 %CI: 0.725-0.909) for stage + EBV DNA8-12w versus 0.654 (95 %CI: 0.542-0.765) for stage + EBV DNA0-2w. CONCLUSION: EBV DNA is dynamic post-radiotherapy, and delayed EBV DNA testing better enriched for higher-risk NPC patients. This implicates trials investigating adjuvant chemotherapy intensification based on early EBV DNA testing.

[ctHPV-DNA based precision oncology for patients with oropharyngeal cancer - Where are we?]

Human papillomavirus (HPV) is an established etiologic factor for cancers in the head and neck region, specifically for Oropharyngeal Squamous Cell Carcinoma (OPSCC). The comparatively good overall survival justifies the current discussion regarding therapy de-escalation for patients with a low-risk profile. In addition to the immunohistochemistry-based biomarker p16INK4a, there is still a need for diagnostic and prognostic biomarkers that allow risk stratification and monitoring during therapy and follow-up of these patients. In recent years, liquid biopsy, especially in the form of plasma samples, has gained importance and is already used to monitor viral DNA in patients with Epstein-Barr virus-associated nasopharyngeal carcinoma. Circulating DNA (ctDNA) released by the tumor into the bloodstream is particularly suitable for a high specificity in detecting virus-associated tumors. Detection of viral E6 and E7 oncogenes in HPV-positive OPSCC is predominantly performed by droplet digital/quantitative PCR as well as next generation sequencing. Detection of circulating HPV-DNA derived from tumor cells (ctHPV-DNA) at diagnosis is associated with advanced tumor stage, locoregional and distant metastases. Longitudinal studies have further demonstrated that detectable and/or increasing ctHPV-DNA levels are associated with treatment failure and disease relapse. However, a standardization of the diagnostic procedure is necessary before introducing liquid biopsy into the clinical routine. In the future, this might allow a valid reflection of disease progression in HPV-positive OPSCC.

Prognostic effect of residual plasma Epstein-Barr viral DNA after induction chemotherapy for locoregionally advanced nasopharyngeal carcinoma

BACKGROUND

To assess the prognostic effect of plasma Epstein-Barr virus (EBV) DNA load after induction chemotherapy (postIC -EBV DNA) on survival outcomes in locoregionally advanced nasopharyngeal carcinoma (LA-NPC).

METHODS

Patients who were diagnosed with LA-NPC between August 2017 and October 2021 were included. The chi-squared test, receiver operating characteristic, Kaplan-Meier survival analysis, and Cox proportional hazard model were used for statistical analysis.

RESULTS

We included 172 patients with EBV DNA-positive LA-NPC in this study. There were 35.5% (n = 61) of patients had plasma residual EBV DNA after induction chemotherapy (IC). Patients with higher EBV DNA before IC (p < 0.001) and advanced nodal stage (p = 0.031) were significantly related to a higher rate of residual postIC -EBV DNA. Patients with detectable postIC -EBV DNA had inferior 3-year locoregional relapse-free survival (LRFS) (86.7% vs. 96.9%, p = 0.020), distant metastasis-free survival (DMFS) (76.8% vs. 94.2%, p < 0.001), disease-free survival (DFS) (68.2% vs. 91.1%, p < 0.001), and overall survival (OS) (87.8% vs. 97.9%, p = 0.044) compared to those with undetectable postIC -EBV DNA. The multivariate prognostic analyses showed that detectable postIC -EBV DNA was the independent prognostic factor related to LRFS (p = 0.032), DMFS (p = 0.010), and DFS (p = 0.004) than those with undetectable postIC -EBV DNA. Pretreatment EBV DNA load had no prognostic effect in the multivariate analyses.

CONCLUSIONS

The monitoring of plasma postIC -EBV DNA has improved prognostication in LA-NPC. Our findings suggest that postIC -EBV DNA may be a robust indicator to identify the optimal candidate for intensive treatment.

Clinical efficacy and biomarker analysis of dual PD-1/CTLA-4 blockade in recurrent/metastatic EBV-associated nasopharyngeal carcinoma

Single-agent checkpoint inhibitor (CPI) activity in Epstein-Barr Virus (EBV) related nasopharyngeal carcinoma (NPC) is limited. Dual CPI shows increased activity in solid cancers. In this single-arm phase II trial (NCT03097939), 40 patients with recurrent/metastatic EBV-positive NPC who failed prior chemotherapy receive nivolumab 3 mg/kg every 2 weeks and ipilimumab 1 mg/kg every 6 weeks. Primary outcome of best overall response rate (BOR) and secondary outcomes (progression-free survival [PFS], clinical benefit rate, adverse events, duration of response, time to progression, overall survival [OS]) are reported. The BOR is 38% with median PFS and OS of 5.3 and 19.5 months, respectively. This regimen is well-tolerated and treatment-related adverse events requiring discontinuation are low. Biomarker analysis shows no correlation of outcomes to PD-L1 expression or tumor mutation burden. While the BOR does not meet pre-planned estimates, patients with low plasma EBV-DNA titre (<7800 IU/ml) trend to better response and PFS. Deep immunophenotyping of pre- and on-treatment tumor biopsies demonstrate early activation of the adaptive immune response, with T-cell cytotoxicity seen in responders prior to any clinically evident response. Immune-subpopulation profiling also identifies specific PD-1 and CTLA-4 expressing CD8 subpopulations that predict for response to combined immune checkpoint blockade in NPC.

The Dynamic Change in Plasma Epstein-Barr Virus DNA Load over a Long-Term Follow-Up Period Predicts Prognosis in Nasopharyngeal Carcinoma

The current study was designed to investigate the changes in the circulating Epstein−Barr virus DNA load (EBV DNA) at various time points before and after treatment and its clinical significance in nasopharyngeal carcinoma (NPC). A total of 142 patients with NPC were prospectively enrolled in this study. The plasma EBV DNA concentration was measured before and after treatment using qPCR. The prognostic values of the EBV DNA load were analyzed using the Kaplan−Meier and Cox regression tests. Following multivariate analysis, our data showed that high pre-EBV DNA loads were associated with significantly poorer distant metastasis free survival (DMFS) and progression free survival (PFS); detectable end-EBV DNA loads were associated with significantly worse loco-regional recurrence free survival (LRRFS) and PFS, and the detecTable 6 months-post-EBV DNA loads were associated with significantly poorer overall survival (OS), DMFS and PFS (p < 0.05). Additionally, combining the pre-EBV DNA load and the stage of the disease, our results showed that patients at stage III-IVA with a low pre-EBV DNA load had similar survival rates as patients at stage II with a low or high pre-EBV DNA load, but had better survival rates than those at stage III-IVA with a high pre-EBV DNA load. Taken together, we showed that the change of the EBV DNA load measured at several time points was more valuable than at any single time point for predicting patients’ survival for NPC. Furthermore, combining the pre-EBV DNA load and the TNM classification could help to formulate an improved prognostic model for this cancer.

[PRMT1 inhibits apoptosis of nasopharyngeal carcinoma cells by promoting RRM2 expression]

OBJECTIVE

To verify whether PRMT1 inhibits apoptosis of nasopharyngeal carcinoma (NPC) cells by promoting RRM2 expression.

METHODS

Immunohistochemistry and Western blotting were performed to detect the relative expression of PRMT1 and RRM2 in NPC and adjacent tissues and in different NPC cell lines and a normal nasal mucosal epithelial cell line (HNEpC). Experiments of PRMT1 or RRM2 overexpression or siRNA-mediated PRMT1 or RRM2 knockdown were carried out in CNE-2 cells to investigate the relationship between PRMT1 and RRM2 expressions using Western blotting. Apoptosis of the transfected cells was detected using Annexin V-FITC/PI apoptosis detection kit, and the production of intracellular reactive oxygen species (ROS) was determined using a ROS detection kit.

RESULTS

Compared with adjacent tissues and HNEpC cells, NPC tissues and cell lines expressed significantly higher levels of PRMT1 and RRM2 (P < 0.05). In CNE-2 cells with PRMT1 or RRM2 overexpression or knockdown, Western blotting demonstrated that PRMT1 could positively regulate the expression of RRM2 (P < 0.05). Overexpression of PRMT1 or RRM2 significantly reduced intracellular ROS production and apoptosis rate of CNE-2 cells (P < 0.05), and PRMT1 or RRM2 knockdown strongly increased ROS production and cell apoptosis (P < 0.05). Overexpression of either PRMT1 or RRM2 significantly decreased the expressions of cleaved caspase-3 and cleaved caspase-8 proteins (P < 0.05), and PRMT1 or RRM2 knockdown obviously promoted their expressions (P < 0.05). PRMT1 knockdown combined with RRM2 overexpression, as compared with PRMT1 knockdown only, significantly decreased ROS production and cell apoptosis (P < 0.05) as well as the protein expressions of cleaved caspase-3 and cleaved caspase-8 in CNE-2 cells (P < 0.05).

CONCLUSION

The high expression of PRMT1 in NPC inhibits apoptosis of NPC cells by promoting the expression of RRM2.

Combination of smoking and Epstein-Barr virus DNA is a predictor of poor prognosis for nasopharyngeal carcinoma: a long-term follow-up retrospective study

BACKGROUND

This retrospective study was performed to determine the prognostic potential of smoking and its combination with pre-treatment plasma Epstein-Barr virus (EBV) DNA levels in patients with nasopharyngeal carcinoma (NPC).

METHODS

Medical records of 1080 non-metastatic NPC patients who received intensity-modulated radiotherapy were reviewed. Male patients were categorized as never and ever smokers, and the smoking amount, duration, and cumulative consumption were used to evaluate dose-dependent effects. Survival outcomes were assessed using Kaplan-Meier survival analysis and the multivariate Cox regression analysis. Propensity score matching (PSM) was constructed.

RESULTS

The 5-year overall survival (OS) was worse for ever smokers than never smokers, and significantly decreased with the increase of smoking amount, duration, and cumulative consumption. Compared with never smokers, the multivariate-adjusted hazard ratio (HR) of death was higher in ever smokers (HR = 1.361, P = 0.049), those smoked ≥20 cigarettes/day (HR = 1.473, P = 0.017), those smoked for ≥30 years (HR = 1.523, P = 0.023), and those cumulative smoked for ≥30 pack-years (HR = 1.649, P = 0.005). The poor prognostic effects of smoking was also confirmed in the PSM analysis. The combination of cumulative smoking consumption and pre-treatment EBV DNA levels was proven to be an independent poor prognostic factor for male NPC, and the risk of death, progression, and distant metastases gradually increased with both factors (P < 0.001).

CONCLUSIONS

Combination of smoking and pre-treatment EBV DNA levels as a predictor of poor prognosis could further improve the risk stratification and prognostication for NPC.

HPV DNA as a Biomarker in Oropharyngeal Cancer: A Step in the Right Direction

Lack of prospectively planned follow-up and minimal characterization of the patient population studied complicate interpretation of circulating human papillomavirus (HPV) DNA as a prognostic biomarker for patients with HPV-associated oropharyngeal carcinoma treated with curative intent. See related article by Berger et al., p. 4292.

Development and validation of a joint model for dynamic prediction of overall survival in nasopharyngeal carcinoma based on longitudinal post-treatment plasma cell-free Epstein-Barr virus DNA load

OBJECTIVES

To develop and validate a joint model for dynamic prediction of overall survival (OS) in nasopharyngeal carcinoma (NPC) based on longitudinal post-treatment plasma cell-free Epstein-Barr virus (cfEBV) DNA load.

PATIENTS AND METHODS

We analyzed 695 patients with non-metastatic NPC and detectable post-treatment cfEBV DNA load who did not receive adjuvant therapy. We fitted the trajectories of post-treatment cfEBV DNA load as a function of time into a linear mixed-effect model and fitted a Cox regression model with covariates including age, T and N stages, and lactate dehydrogenase level. Finally, we combined both via joint modeling to develop and validate our dynamic model.

RESULTS

A strong positive correlation was found between the individual longitudinal post-treatment cfEBV DNA load and the risk of death from any cause (P < 0.001). We developed a joint model capable of providing subject-specific dynamic prediction of conditional OS based on the evolution of the individual plasma cfEBV DNA load trajectory. The joint model showed reliable performance in both training and validation cohorts, with a large area under the curve (interquartile range [IQR]: training cohort, 0.775-0.850; validation cohort, 0.826-0.900) and low prediction errors (IQR: training cohort, 0.017-0.078; validation cohort, 0.034 -0.071). An increasing amount of data on cfEBV DNA load was associated with better model performance.

CONCLUSION

Our model provided reliable subject-specific dynamic prediction of conditional OS, which could help guide individualized post-treatment surveillance, risk stratification, and management of NPC in the future.

Individualized circulating tumor DNA monitoring in head and neck squamous cell carcinoma

There is no useful biomarker to evaluate treatment response and early relapse in head and neck squamous cell carcinoma (HNSCC). Circulating tumor DNA (ctDNA) is a promising biomarker for detecting minimal residual diseases and monitoring treatment effect. We investigated whether individualized ctDNA analysis could help monitor treatment response and relapse in HNSCC. Mutation analysis of tumor and peripheral blood mononuclear cell (PBMC) DNAs of 26 patients with HNSCC was performed using a custom squamous cell carcinoma (SCC) panel. The identified individualized mutated genes were defined as ctDNA candidates. We investigated whether frequent ctDNA monitoring via digital PCR (dPCR) is clinically valid for HNSCC patients. TP53 was the most frequently mutated gene and was detected in 14 of 24 cases (58.2%), wherein two cases were excluded owing to the absence of tumor-specific mutations in the SCC panel. Six cases were excluded because of undesignable and unusable primer-probes for dPCR. Longitudinal ctDNA was monitored in a total of 18 cases. In seven cases, ctDNA tested positive again or did not test negative, and all seven cases relapsed after initial curative treatment. In 11 cases, after initial curative treatment, ctDNA remained negative and patients were alive without recurrence. Patients who remained negative for ctDNA during follow-up after initial curative treatment (n = 11) had a significantly better prognosis than those who reverted to ctDNA positivity (n = 7; p < 0.0001; log-rank test). Individualized ctDNA monitoring using SCC panel and dPCR might be a novel and promising biomarker for HNSCC.

Development and validation of a risk prediction score for patients with nasopharyngeal carcinoma

Background

We aimed to develop and validate a predictive model for the overall survival (OS) of patients with nasopharyngeal carcinoma (NPC).

Methods

Overall, 519 patients were retrospectively reviewed in this study. In addition, a random forest model was used to identify significant prognostic factors for OS among NPC patients. Then, calibration plot and concordance index (C-index) were utilized to evaluate the predictive accuracy of the nomogram model.

Results

We used a random forest model to select the three most important features, dNLR, HGB and EBV DNA, which were significantly associated with the OS of NPC patients. Furthermore, the C-index of our model for OS were 0.733 (95% CI 0.673 ~ 0.793) and 0.772 (95% CI 0.691 ~ 0.853) in the two cohorts, which was significantly higher than that of the TNM stage, treatment, and EBV DNA. Based on the model risk score, patients were divided into two groups, associated with low-risk and high-risk. Kaplan–Meier curves demonstrated that the two subgroups were significantly associated with OS in the primary cohort, as well as in the validation cohort. The nomogram for OS was established using the risk score, TNM stage and EBV DNA in the two cohorts. The nomogram achieved a higher C-index of 0.783 (95% CI 0.730 ~ 0.836) than that of the risk score model 0.733 (95% CI 0.673 ~ 0.793) in the primary cohort (P = 0.005).

Conclusions

The established risk score model and nomogram resulted in more accurate prognostic prediction for individual patient with NPC.

Epstein-Barr virus nuclear antigen-1 is useful as therapeutic efficacy marker in serum but not in saliva of nasopharyngeal cancer patients who underwent radiotherapy

Introduction

Nasopharyngeal carcinoma (NPC) is a multifactorial disease with genetic, viral, environmental and lifestyle-related risk factors. Epstein–Barr virus (EBV) can promote the oncogenic transformation of an infected cell into malignant. EBV encodes many stimulating products including Epstein–Barr virus nuclear antigen-1 (EBNA-1) which plays a key role in the regulation of gene expression and replication of the genome in the latent period of infection. EBNA-1 in serum and tumour tissue of NPC patients correlates with NPC prognosis. Moreover, the presence of EBV DNA in serum samples from NPC patients’ blood circulation can be used as an early marker in the diagnosis of NPC.

Objective

The objective of this study was to find effective methods for monitoring the progress of NPC patients undergoing radiotherapy and therapeutic efficacy by observing the changes in EBV DNA in serum and saliva.

Methodology

The pre-experimental design compared blood and saliva taken from a pre-test and post-test group of NPC patients before and after radiation therapy. The concentration of EBV DNA was measured in the serum and saliva after amplification using quantitative polymerase chain reaction (qPCR) with compatible primers for the EBNA-1 gene. The data were statistically analysed by paired T-test.

Results

Highly significant (p = 0.0001) increase in cycle threshold qPCR and decrease in the mean concentration of EBV DNA (p = 0.0001) were observed in serum samples, but no significant changes were observed in saliva.

Conclusions

The results suggest that EBV DNA in serum can be used as the gold standard and a marker for monitoring the response to radiation therapy in NPC patients, whereas the examination of EBV DNA from saliva samples is not accurate and thus, not appropriate.