Quantitative association of tobacco smoking with the risk of nasopharyngeal carcinoma: a comprehensive meta-analysis of studies conducted between 1979 and 2011

Epidemiology of nasopharyngeal carcinoma: current insights and future outlook

Nasopharyngeal carcinoma (NPC) is characterised by its remarkable geographical and ethnic distribution. The interplay between genetic susceptibility, environmental exposures, and Epstein-Barr virus (EBV) infections is indicated in the development of NPC. Exposure to tobacco smoking, dietary factors, and inhalants has been associated with the risk of NPC. Genetic association studies have revealed NPC-associated susceptibility loci, including genes involved in immune responses, xenobiotic metabolism, genome maintenance, and cell cycle regulation. EBV exposure timing and strain variation might play a role in its carcinogenicity, although further investigations are required. Other factors including medical history and oral hygiene have been implicated in NPC. Prevention strategies, including primary prevention and secondary prevention through early detection, are vital in reducing mortality and morbidity of NPC. The current review discusses the global and regional distribution of NPC incidences, the risk factors associated with NPC, and the public health implications of these insights. Future investigations should consider international, large-scale prospective studies to elucidate the mechanisms underlying NPC pathogenesis and develop individualized interventions for NPC.

Effects of ambient temperature, relative humidity and absolute humidity on risk of nasopharyngeal carcinoma in China

Nasopharyngeal carcinoma (NPC) has a unique geographic distribution. It is unknown whether meteorological factors are related to the incidence of NPC. To investigate the effect of ambient temperature, relative humidity (RH), and absolute humidity (AH) on the incidence of NPC, we collected the incidence rate of NPC in 2016 and meteorological data from 2006 to 2016 from 484 cities and counties across 31 provinces in China. Generalized additive models with quasi-Poisson regression and generalized linear models with natural cubic splines were employed respectively to elucidate the nonlinear relationships and specify the partial linear relationships. Subgroup and interactive analysis were also conducted. Temperature (R2 = 0.68, p < .001), RH (R2 = 0.47, p < .001), and AH (R2 = 0.70, p < .001) exhibited nonlinear correlations with NPC incidence rate. The risk of NPC incidence increased by 20.3% (95% confidence intervals [CI]: [18.9%, 21.7%]) per 1°C increase in temperature, by 6.3% (95% CI: [5.3%, 7.2%]) per 1% increase in RH, and by 32.2% (95% CI: [30.7%, 33.7%]) per 1 g/m3 increase in AH, between their the 25th and the 99th percentiles. In addition, the combination of low temperature and low RH was also related to increased risk (relative risk: 1.60, 95% CI: [1.18, 2.17]). Males and eastern or rural populations tended to be more vulnerable. In summary, this study suggests that ambient temperature, RH, and particularly AH are associated with the risk of NPC incidence.

Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios as Predictors of Dysphagia Severity and Quality of Life in Nasopharyngeal Cancer Patients after Intensity Modulated Radiotherapy (IMRT)

Background: Patients treated with definitive radiotherapy for nasopharyngeal carcinoma (NPC) develop severe dysphagia, affecting their quality of life. Traditional prognosis biomarkers are insufficient, leading to a search for new predictors like neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). Methods: We retrospectively enrolled 44 NPC patients who underwent definitive radiotherapy between 2010 and 2018. EQUATOR and STROBE network guidelines were adopted. Pre-treatment evaluations were conducted, and post-treatment oropharyngeal dysphagia was assessed using the Sydney Swallow Questionnaire (SSQ) and FEES, then assigning a Dysphagia Outcome and Severity Scale (DOSS) level. Patients were divided based on NLR and PLR cut-offs, comparing subjective dysphagia (SSQ) scores and DOSS results at baseline and after a 5-year follow-up. Multiple linear regression was used for analysis. Results: At baseline, the mean NLR was 2.52 ± 1.10, and the PLR was 208.40 ± 94.35. Multivariate analysis indicated NLR and PLR as significant predictors of DOSS outcomes (p < 0.001). Conclusions: Baseline inflammation markers, such as NLR and PLR, may be used to predict dysphagia severity in NPC patients undergoing definitive radiotherapy. These markers could help identify patients at higher risk for severe dysphagia and implement tailored therapeutic and rehabilitative strategies to improve their quality of life. Further studies with larger cohorts are needed to confirm these findings and explore additional prognostic factors for dysphagia outcomes in NPC patients.

Systematic replication of smoking disease associations using survey responses and EHR data in the All of Us Research Program

OBJECTIVE

The All of Us Research Program (All of Us) aims to recruit over a million participants to further precision medicine. Essential to the verification of biobanks is a replication of known associations to establish validity. Here, we evaluated how well All of Us data replicated known cigarette smoking associations.

MATERIALS AND METHODS

We defined smoking exposure as follows: (1) an EHR Smoking exposure that used International Classification of Disease codes; (2) participant provided information (PPI) Ever Smoking; and, (3) PPI Current Smoking, both from the lifestyle survey. We performed a phenome-wide association study (PheWAS) for each smoking exposure measurement type. For each, we compared the effect sizes derived from the PheWAS to published meta-analyses that studied cigarette smoking from PubMed. We defined two levels of replication of meta-analyses: (1) nominally replicated: which required agreement of direction of effect size, and (2) fully replicated: which required overlap of confidence intervals.

RESULTS

PheWASes with EHR Smoking, PPI Ever Smoking, and PPI Current Smoking revealed 736, 492, and 639 phenome-wide significant associations, respectively. We identified 165 meta-analyses representing 99 distinct phenotypes that could be matched to EHR phenotypes. At P < .05, 74 were nominally replicated and 55 were fully replicated. At P < 2.68 × 10-5 (Bonferroni threshold), 58 were nominally replicated and 40 were fully replicated.

DISCUSSION

Most phenotypes found in published meta-analyses associated with smoking were nominally replicated in All of Us. Both survey and EHR definitions for smoking produced similar results.

CONCLUSION

This study demonstrated the feasibility of studying common exposures using All of Us data.

M. N. Mydin RB, Che Halim H, Musa MY. A Systematic Review on Clinico-Aetiopathological Trends of Nasopharyngeal Cancer in Asia

BACKGROUND

Nasopharyngeal cancer (NPC) is a type of malignancy that is highly prevalent in Asian countries. Therefore, an understanding between NPC epidemiological trend, the clinico-pathological and aetiological profiles are needed. This systematic review focuses on asian countries demographic and clinico-pathological presentation reported in 9982 NPC cases diagnosed from the year 2010 to 2021.

METHODOLOGY

Data were extracted from databases, such as PubMed, Springer Link, Science Direct, Google Scholar and general search engines, by using pre-determined keywords (e.g. clinico-pathological data, age, sex, tumour stage, nasopharyngeal cancer, nasopharyngeal carcinoma, naso-pharynx and cancer in Asia).

RESULTS AND CONCLUSION

Findings from our systematic review shows that from 2010 to 2021, males in age range below 50 years old are at a higher risk of developing NPC in Asia. NPC is mostly diagnosed at advanced stage in Asia, which is likely due to the deep-seated location of the cancer. Type III NPC and EBV proteins (EBNA1 and LMP2A) are frequently associated with reported EBV-positive NPC cases in Asian countries. Meanwhile, NPC type I, II, and III are associated with EBV-negative NPC cases in Asia. Human leucocyte antigen (HLA) alleles (A2, B27, and B46) are frequently present in reported EBV-negative NPC cases in Asia. In Asia, males below 50 years old are more prone to NPC and often diagnosed at late stage. EBV-positive and EBV-negative NPC in Asia have unique histological profiles. Systemic approach of this study may help to provide better knowledge on reported NPC cases especially on the risk factors and clinical presentation focusing in Asian countries.

Toripalimab Plus Chemotherapy for Recurrent or Metastatic Nasopharyngeal Carcinoma: The JUPITER-02 Randomized Clinical Trial

Importance

There are currently no therapies approved by the US Food and Drug Administration for nasopharyngeal carcinoma (NPC). Gemcitabine-cisplatin is the current standard of care for the first-line treatment of recurrent or metastatic NPC (RM-NPC).

Objective

To determine whether toripalimab in combination with gemcitabine-cisplatin will significantly improve progression-free survival and overall survival as first-line treatment for RM-NPC, compared with gemcitabine-cisplatin alone.

Design, Setting, and Participants

JUPITER-02 is an international, multicenter, randomized, double-blind phase 3 study conducted in NPC-endemic regions, including mainland China, Taiwan, and Singapore. From November 10, 2018, to October 20, 2019, 289 patients with RM-NPC with no prior systemic chemotherapy in the RM setting were enrolled from 35 participating centers.

Interventions

Patients were randomized (1:1) to receive toripalimab (240 mg [n = 146]) or placebo (n = 143) in combination with gemcitabine-cisplatin for up to 6 cycles, followed by maintenance with toripalimab or placebo until disease progression, intolerable toxicity, or completion of 2 years of treatment.

Main Outcome

Progression-free survival as assessed by a blinded independent central review. Secondary end points included objective response rate, overall survival, progression-free survival assessed by investigator, duration of response, and safety.

Results

Among the 289 patients enrolled (median age, 46 [IQR, 38-53 years; 17% female), at the final progression-free survival analysis, toripalimab treatment had a significantly longer progression-free survival than placebo (median, 21.4 vs 8.2 months; HR, 0.52 [95% CI, 0.37-0.73]). With a median survival follow-up of 36.0 months, a significant improvement in overall survival was identified with toripalimab over placebo (hazard ratio [HR], 0.63 [95% CI, 0.45-0.89]; 2-sided P = .008). The median overall survival was not reached in the toripalimab group, while it was 33.7 months in the placebo group. A consistent effect on overall survival, favoring toripalimab, was found in subgroups with high and low PD-L1 (programmed death-ligand 1) expression. The incidence of all adverse events, grade 3 or greater adverse events, and fatal adverse events were similar between the 2 groups. However, adverse events leading to discontinuation of toripalimab or placebo (11.6% vs 4.9%), immune-related adverse events (54.1% vs 21.7%), and grade 3 or greater immune-related adverse events (9.6% vs 1.4%) were more frequent in the toripalimab group.

Conclusions and Relevance

The addition of toripalimab to chemotherapy as first-line treatment for RM-NPC provided statistically significant and clinically meaningful progression-free survival and overall survival benefits compared with chemotherapy alone, with a manageable safety profile. These findings support the use of toripalimab plus gemcitabine-cisplatin as the new standard of care for this patient population.

Trial Registration

ClinicalTrials.gov Identifier: NCT03581786.

Nasopharyngeal Cancer Incidence and Mortality in 185 Countries in 2020 and the Projected Burden in 2040: Population-Based Global Epidemiological Profiling

BACKGROUND

Nasopharyngeal cancer (NPC) is one of the most common head and neck cancers.

OBJECTIVE

This study describes the global epidemiological profiles of NPC incidence and mortality in 185 countries in 2020 and the projected burden in 2040.

METHODS

The estimated numbers of NPC cases and deaths were retrieved from the GLOBOCAN 2020 data set. Age-standardized incidence rates (ASIRs) and age-standardized mortality rates (ASMRs) were calculated using the world standard. The future number of NPC cases and deaths by 2040 were estimated based on global demographic projections.

RESULTS

Globally, approximately 133,354 cases and 80,008 deaths from NPC were estimated in 2020 corresponding to ASIRs and ASMRs of 1.5 and 0.9 per 100,000 person-years, respectively. The largest numbers of both global cases and deaths from NPC occurred in Eastern Asia (65,866/133,354, 49.39% and 36,453/80,008, 45.56%, respectively), in which China contributed most to this burden (62,444/133,354, 46.82% and 34,810/80,008, 43.50%, respectively). The ASIRs and ASMRs in men were approximately 3-fold higher than those in women. Incidence rates varied across world regions, with the highest ASIRs for both men and women detected in South-Eastern Asia (7.7 and 2.5 per 100,000 person-years, respectively) and Eastern Asia (3.9 and 1.5 per 100,000 person-years, respectively). The highest ASMRs for both men and women were found in South-Eastern Asia (5.4 and 1.5 per 100,000 person-years, respectively). By 2040, the annual number of cases and deaths will increase to 179,476 (46,122/133,354, a 34.58% increase from the year 2020) and 113,851 (33,843/80,008, a 42.29% increase), respectively.

CONCLUSIONS

Disparities in NPC incidence and mortality persist worldwide. Our study highlights the urgent need to develop and accelerate NPC control initiatives to tackle the NPC burden in certain regions and countries (eg, South-Eastern Asia, China).

Exclusive waterpipe smoking and the risk of nasopharynx cancer in Vietnamese men, a prospective cohort study

Tobacco smoking is carcinogenic to humans. Besides cigarettes, the most common form of tobacco smoking, there was sparse evidence of waterpipe's carcinogenicity-induced nasopharyngeal cancer (NPC). This study investigated the association between waterpipe smoking and NPC mortality. Our study followed up with 20,144 eligible man participants from nine northern Vietnam communes between 2007 and 2019. Face-to-face interviews were conducted to gather data on exclusive waterpipe and cigarette smoking and dietary intake using structured semi-quantitative food frequency and lifestyle questionnaires. Nasopharyngeal cancer was determined by accessing the medical records at the state health facilities. We estimated the Cox proportional hazard ratio and 95% confidence intervals, HR (95% CI). The proportion of never smokers, exclusive waterpipe, exclusive cigarette, and dual waterpipe and cigarette smokers was 55.8%, 14.5%, 16.6%, and 13.1%, respectively. Exclusively waterpipe smokers increased the risk of NPC death compared to exclusively cigarette smokers, HR (95% CI): 4.51 (1.25, 16.31), p = 0.022. A dose-dependent positive relationship between NPC and exclusive waterpipe smoking was significantly seen for higher intensity HR (95% CI): 1.35 (1.07, 1.71), earlier age of smoking initiation HR (95% CI): 1.26 (1.06, 1.50), longer duration HR (95% CI): 1.31 (1.04, 1.66), and the cumulative number of a smoke lifetime HR (95% CI): 1.37 (1.08, 1.74). We observed a significant positive association between exclusive waterpipe smoking and NPC in men. The findings suggested that waterpipe smoking is likely more harmful than cigarettes in developing this cancer. A firm tobacco control against waterpipe smoking is highly recommended.

Epidemiological, Clinicopathological and Prognosis Features of Moroccan Patients with Nasopharyngeal Carcinoma

PROPOSAL

A distinct epidemiology, etiology, clinical characteristics, and therapeutic outcomes characterize nasopharyngeal carcinoma (NPC) from other head and neck cancers. An actualized analysis of NPC patients' features enables a global view of NPC management. Accordingly, the current study investigated the epidemiological and clinical characteristics of Moroccan patients with NPC, as well as their 4-years survival outcomes and influencing prognostic factors.

METHODS

We prospectively analyzed data of 142 histologically confirmed Moroccan patients with NPC between October 2016 and February 2019. Kaplan-Meier and Cox regression analyses were used to assess predictive prognostic factors related to NPC. All analyses were conducted using SPSS version 21 statistical software.

RESULTS

In the present study, a net male predominance was found, with a mean age of 44±16.3 years old. Advanced stages of NPC were observed in 64.1% of patients, and 32.4% of patients presented with distant metastasis at diagnosis. The 4-years overall survival, locoregional relapse-free survival, distant metastasis-free survival and progression-free survival were 68.0%, 63.0%, 53.9%, and 39.9%, respectively. Age, N category and distant metastasis were identified as the most important independent prognosis factors for NPC in this cohort (p<0.05).

CONCLUSION

In conclusion, NPC affects young adults and is frequently diagnosed at advanced disease stages, impacting therefore negatively patients survival; which is in line with data from endemic areas for NPC. The current study clearly highlights that a greater attention should be directed to improving the management of this aggressive malignancy.

Whole-Exome Sequencing Study of Familial Nasopharyngeal Carcinoma and Its Implication for Identifying High-Risk Individuals

BACKGROUND

Nasopharyngeal carcinoma (NPC) is closely associated with genetic factors and Epstein-Barr virus infection, showing strong familial aggregation. Individuals with a family history suffer elevated NPC risk, requiring effective genetic counseling for risk stratification and individualized prevention.

METHODS

We performed whole-exome sequencing on 502 familial NPC patients and 404 unaffected relatives and controls. We systematically evaluated the established cancer predisposition genes and investigated novel NPC susceptibility genes, making comparisons with 21 other familial cancers in the UK biobank (N = 5218).

RESULTS

Rare pathogenic mutations in the established cancer predisposition genes were observed in familial NPC patients, including ERCC2 (1.39%), TP63 (1.00%), MUTYH (0.80%), and BRCA1 (0.80%). Additionally, 6 novel susceptibility genes were identified. RAD54L, involved in the DNA repair pathway together with ERCC2, MUTYH, and BRCA1, showed the highest frequency (4.18%) in familial NPC. Enrichment analysis found mutations in TP63 were enriched in familial NPC, and RAD54L and EML2 were enriched in both NPC and other Epstein-Barr virus-associated cancers. Besides rare variants, common variants reported in the studies of sporadic NPC were also associated with familial NPC risk. Individuals in the top quantile of common variant-derived genetic risk score while carrying rare variants exhibited increased NPC risk (odds ratio = 13.47, 95% confidence interval = 6.33 to 28.68, P = 1.48 × 10-11); men in this risk group showed a cumulative lifetime risk of 24.19%, much higher than those in the bottom common variant-derived genetic risk score quantile and without rare variants (2.04%).

CONCLUSIONS

This study expands the catalog of NPC susceptibility genes and provides the potential for risk stratification of individuals with an NPC family history.

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.

Occupational risk variation of nasopharyngeal cancer in the Nordic countries

Background

The aim of this study was to estimate occupational risk variation in the incidence of nasopharyngeal cancer (NPC) in a large population-based cohort of the Nordic Occupational Cancer (NOCCA) study.

Methods

This study is based on a cohort of almost 15 million persons from Denmark, Finland, Iceland, Norway and Sweden, with 2898 nasopharyngeal cancer cases diagnosed in 1961–2005. The data on occupations were gathered from population censuses and cancer data from the national cancer registries. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were estimated using the national NPC incidence rates as the reference.

Results

There were 1980 male and 918 female NPC patients. The highest SIRs of NPC were observed among male waiters (SIR 3.69, 95% CI 1.91–6.45) and cooks and stewards (SIR 2.24, 95% CI 1.16–3.91). Among women, launderers had the highest SIR of NPC (2.04, 95% CI 1.02–3.65). Significantly decreased SIRs were found among male farmers (SIR 0.79, 95% CI 0.68–0.92) and male textile workers (SIR 0.49, 95% CI 0.22–0.93).

Conclusions

This study suggests that NPC may be associated with several work-related exposure agents such as smoking, kitchen air pollution and solvents. In future, occupational exposure-risk relations should be studied to understand more about causality and to assess effective prevention strategies.

Development and validation of the health belief model questionnaire to promote smoking cessation for nasopharyngeal cancer prevention: a cross-sectional study

OBJECTIVE

Lifestyle-induced nasopharyngeal carcinoma is a serious but preventable risk factor. This study serves to develop and validate a questionnaire that aims to predict the health behavioural intention on smoking cessation in Sarawak, Malaysia using the Health Belief Model (HBM).

DESIGN

A cross-sectional study.

SETTING

Urban and suburban areas in Sarawak, Malaysia.

PARTICIPANTS

The preliminary items of the instrument were developed after extensive literature review. The instrument was translated into the Malay language using the forward-backwards method before commencing with the content validity by a panel of 10 experts. Face validity was done both quantitatively and qualitatively by 10 smokers. The construct validity of the instrument was evaluated through exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). A total of 100 smokers participated in phase 1 for EFA, while 171 smokers participated in phase 2 for CFA. Internal consistency was measured using Cronbach's alpha coefficients to evaluate the reliability.

RESULTS

In the exploratory stage, the factor loading of each item remained within the acceptable threshold. The final revised CFA yielded appropriate fit of the seven-factor model with the following model fit indices: χ²=641.705; df=500; p<0.001; comparative fit index=0.953; Tucker-Lewis Index=0.948; root mean square error of approximation=0.041. Satisfactory convergent validity and divergent validity were shown, with the exception of one pairwise construct. The internal reliability of these scales was above the desirable threshold, with Cronbach's alpha coefficients ranging from 0.705 to 0.864 and 0.838 to 0.889 in phases 1 and 2, respectively.

CONCLUSIONS

The study substantiated the instrument to be valid and reliable for predicting smokers' health behavioural intention to reduce cancer risk. The instrument is made up of 34 items, categorised into two sections, six HBM constructs and health behavioural intention. The instrument can be utilised for other smoking cessation-related cancers in different at-risk populations.

A novel causal model for nasopharyngeal carcinoma

The development of nasopharyngeal carcinoma (NPC) and its unique geographic distribution have long been attributed to a combination of dietary intake of salt-preserved fish, inherited susceptibility, and early-life infection with the Epstein-Barr virus (EBV). New findings from our large, rigorously designed, population-based case-control study of NPC in southern China have enabled substantial revision of this causal model. Here, we briefly summarize these results and provide an updated model of the etiology of NPC. Our new research identifies two EBV genetic variants that may be causally involved in the majority of NPC in southern China, and suggests the rise of modern environmental co-factors accompanying cultural and economic transformation in NPC-endemic regions. These discoveries can be translated directly into clinical and public health advances, including improvement of indoor air quality and oral health, development of an EBV vaccine, enhanced screening strategies, and improved risk prediction. Greater understanding of the roles of environmental, genetic, and viral risk factors can reveal the extent to which these agents act independently or jointly on NPC development. The history of NPC research demonstrates how epidemiology can shed light on the interplay of genes, environment, and infections in carcinogenesis, and how this knowledge can be harnessed for cancer prevention and control.

Global, regional, and national burden of cancers attributable to tobacco smoking in 204 countries and territories, 1990-2019

BACKGROUND

Cancers are leading causes of mortality and morbidity, with smoking being recognized as a significant risk factor for many types of cancer. We aimed to report the cancer burden attributable to tobacco smoking by sex, age, socio-demographic index (SDI), and cancer type in 204 countries and territories from 1990 to 2019.

METHODS

The burden of cancers attributable to smoking was reported between 1990 and 2019, based upon the Comparative Risk Assessment approach used in the Global Burden of Disease (GBD) study 2019.

RESULTS

Globally, in 2019 there were an estimated 2.5 million cancer-related deaths (95% UI: 2.3 to 2.7) and 56.4 million DALYs (51.3 to 61.7) attributable to smoking. The global age-standardized death and DALY rates of cancers attributable to smoking per 100,000 decreased by 23.0% (-29.5 to -15.8) and 28.6% (-35.1 to -21.5), respectively, over the period 1990-2019. Central Europe (50.4 [44.4 to 57.6]) and Western Sub-Saharan Africa (6.7 [5.7 to 8.0]) had the highest and lowest age-standardized death rates, respectively, for cancers attributable to smoking. In 2019, the age-standardized DALY rate of cancers attributable to smoking was highest in Greenland (2224.0 [1804.5 to 2678.8]) and lowest in Ethiopia (72.2 [51.2 to 98.0]). Also in 2019, the global number of DALYs was highest in the 65-69 age group and there was a positive association between SDI and the age-standardized DALY rate.

CONCLUSIONS

The results of this study clearly illustrate that renewed efforts are required to increase utilization of evidence-based smoking cessation support in order to reduce the burden of smoking-related diseases.

Neutrophil-to-lymphocyte ratio trend: A novel prognostic predictor in patients with nasopharyngeal carcinoma receiving radiotherapy

BACKGROUND

Peripheral neutrophil-lymphocyte ratio (NLR), reflecting immune-inflammation status, shows great potential for tumor progression and outcome. Pre-treatment NLR does not fully reflect the immune-inflammatory response to treatment. This study aimed to introduce the NLR trend as a new indicator and to investigate its prognostic value in patients with nasopharyngeal carcinoma receiving radiotherapy.

METHODS

This retrospective study evaluated patients with nasopharyngeal carcinoma treated with radiotherapy. The NLR trend value was calculated from the fitted line gradient via the NLRs before, during (at least once), and after each patient's first radiotherapy. The Kaplan-Meier curve and log-rank test were used to calculate and compare survival outcomes of different pretreatment NLRs and NLR trends for progression-free survival, locoregional recurrence-free survival (LRFS), and overall survival at 3 and 5 years. Multivariate Cox regression analyses were performed to assess the association between the NLR trend plus 3- and 5-year overall survival.

RESULTS

The study included 528 patients. A lower NLR trend predicted worse progression-free survival, LRFS, plus 3- and 5-year overall survival. Multivariate Cox regression analysis showed that the NLR trend independently predicted 3- and 5-year overall survival. Sub-group analysis showed that the prognosis of patients with a low pretreatment NLR and a high NLR trend were superior to those of other groups.

CONCLUSION

The NLR trend independently predicted the prognosis of patients with nasopharyngeal carcinoma receiving radiotherapy. The NLR trend and the pretreatment NLR combination is more precise than pretreatment NLR in predicting prognosis. A high NLR trend may be evidence of a positive immune response to radiotherapy in patients with nasopharyngeal carcinoma.

Whole exome sequencing identifies the potential role of genes involved in p53 pathway in Nasopharyngeal Carcinoma from Northeast India

Nasopharyngeal Carcinoma (NPC) found to be dependent on geographical and racial variation and is more prevalent in Northeast (NE) India. WES-based study was conducted in three states (tribes); Nagaland (Naga), Mizoram (Mizo) and Manipur (Manipuri), which provided an overview of germline variants involved inthemajor signaling pathways. Validation and recurrence assessment of WES data confirmed the risk effect of STEAP3_rs138941861 and JAG1_rs2273059, and the protective role of PARP4_rs17080653 and TGFBR1_rs11568778 variants, where STEAP3_rs138941861conferring Arg290His substitution was the only exonic non-synonymous variant and to be located in proximity to the linking region between the transmembrane and oxidoreductasedomainsof STEAP3 protein, andaffectedits structural and functional dynamics by altering the Electrostatic Potential around this connecting region. Moreover, these significantly associated variants having deleterious effect were observed to have interactions in p53 signaling pathway which emphasizes the importance of this pathway in the causation of NPC.

A Five-MicroRNA Signature Predicts the Prognosis in Nasopharyngeal Carcinoma

Background

There is no effective prognostic signature that could predict the prognosis of nasopharyngeal carcinoma (NPC).

Methods

We constructed a prognostic signature based on five microRNAs using random forest and Least Absolute Shrinkage And Selection Operator (LASSO) algorithm on the GSE32960 cohort (N = 213). We verified its prognostic value using three independent external validation cohorts (GSE36682, N = 62; GSE70970, N = 246; and TCGA-HNSC, N = 523). Through principal component analysis, receiver operating characteristic curve analysis, and C-index calculation, we confirmed the predictive accuracy of this prognostic signature.

Results

We calculated the risk score based on the LASSO algorithm and divided the patients into high- and low-risk groups according to the calculated optimal cutoff value. The patients in the high-risk group tended to have a worse prognosis outcome and chemotherapy response. The time-dependent receiver operating characteristic curve showed that the 1-year overall survival rate of the five-microRNA signature had an area under the curve of more than 0.83. A functional annotation analysis of the five-microRNA signature showed that the patients in the high-risk group were usually accompanied by activation of DNA repair and MYC-target pathways, while the patients in the low-risk group had higher immune-related pathway signals.

Conclusions

We constructed a five-microRNA prognostic signature, which could accurately predict the prognosis of nasopharyngeal carcinoma, and constructed a nomogram that could conveniently predict the overall survival of patients.

Smoking and nasopharyngeal cancer: individual data meta-analysis of six prospective studies on 334 935 men

BACKGROUND

The role of smoking in nasopharyngeal carcinoma (NPC) remains uncertain, especially in endemic regions. We conducted an individual participant data (IPD) meta-analysis of prospective cohort studies to investigate the associations between smoking exposure and risk of NPC.

METHODS

We obtained individual participant data of 334 935 male participants from six eligible population-based cohorts in NPC-endemic regions, including two each in Guangzhou and Taiwan, and one each in Hong Kong and Singapore. We used one- and two-stage approaches IPD meta-analysis and Cox proportional hazard models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of NPC for smoking exposure adjusting for age and drinking status.

RESULTS

During 2 961 315 person-years of follow-up, 399 NPC evens were ascertained. Risks of NPC were higher in ever versus never smokers (HRone-stage = 1.32, 95% CI = 1.07-1.63, P = 0.0088; HRtwo-stage = 1.27, 1.01-1.60, 0.04). These positive associations appeared to be stronger in ever smokers who consumed 16+ cigarettes/day (HRone-stage = 1.67, 95% CI = 1.29-2.16, P = 0.0001), and in those who started smoking at age younger than 16 (2.16, 1.33-3.50, 0.0103), with dose-response relationships (P-values for trend = 0.0028 and 0.0103, respectively). Quitting (versus daily smoking) showed a small reduced risk (stopped for 5+ years: HRone-stage = 0.91, 95% CI = 0.60-1.39, P = 0.66; for former smokers: HRtwo-stage = 0.84, 0.61-1.14, 0.26).

CONCLUSIONS

This first IPD meta-analysis from six prospective cohorts in endemic regions has provided robust observational evidence that smoking increased NPC risk in men. NPC should be added to the 12-16 cancer sites known to be tobacco-related cancers. Strong tobacco control policies, preventing young individuals from smoking, would reduce NPC risk in endemic regions.

Impact of smoking on survival in nasopharyngeal carcinoma: A cohort study with 23,325 patients diagnosed from 1990 to 2016

BACKGROUND

We aimed to compare the survival outcomes of patients with nasopharyngeal carcinoma (NPC) who had different smoking behaviors and were treated with two- or three-dimensional radiotherapy (2D/3DRT) or intensity-modulated radiotherapy (IMRT) with a long-term follow up.

METHODS

From 1990 to 2016, 23,325 patients with NPC were included. The primary endpoint of this study was overall survival (OS). The log-rank test and Cox proportional hazards regression model were used to assess the patients' survival outcomes.

RESULTS

The 5-year OS rates in the entire cohort were 76.4%, 68.9%, and 79.8% in the former, current, and never smokers, respectively. In the IMRT cohort, the OS rates showed the same trend. Compared with the never smokers, the 5-year distant metastasis-free survival (DMFS) was lower in the former (P = 0.004) and current smokers (P < 0.001). In the multivariate analysis of the IMRT cohort, the risk of death (P = 0.003) and recurrence (P = 0.027) was higher in the current smokers, while the risk of metastasis was higher in the former and current smokers (P = 0.031 and P = 0.019, respectively) than the never smokers. A total of 53.9% of the effect of smoking status on OS was through sex, age, and Epstein-Barr virus DNA, which were significant mediators.

CONCLUSION

In the IMRT era, being a former smoker or current smoker was an independent risk factor for DMFS. The difference in OS and locoregional relapse-free survival was significant only between the current smokers and never smokers.

The Evolving Epidemiology of Nasopharyngeal Carcinoma

BACKGROUND

The epidemiology of nasopharyngeal carcinoma (NPC) has long been a source of fascination due to the malignancy's striking geographic distribution, the involvement of the oncogenic Epstein-Barr virus (EBV), the unique association with intake of Chinese-style salt-preserved fish, and etiologic heterogeneity by histologic subtype.

METHODS

This review summarizes the current epidemiologic literature on NPC, highlighting recent results from our population-based case-control study in southern China.

RESULTS

Findings from our case-control study provide new insight into the epidemiology of NPC, including a diminished role of Chinese-style salt-preserved fish, a profound impact of EBV genetic sequence variation, modest positive associations with passive smoking and household air pollution, and possible effects of oral health and the oral microbiome. Recent findings from other studies include a protective association with infectious mononucleosis, suggesting a causal role of early EBV infection; familial risk conferred by shared genetic variation in the host antibody-mediated immune response to EBV infection; and an unclear association with occupational exposure to formaldehyde.

CONCLUSIONS

To shed further light on the interplay of environmental, genetic, and viral causes of NPC, large pooled studies must accumulate sufficient cases with detailed exposure data.

IMPACT

New epidemiologic findings have reshaped the causal model for NPC.

Occupational exposures and risk of nasopharyngeal carcinoma in a high-risk area: A population-based case-control study

BACKGROUND

The potential role of occupational exposures in the development of nasopharyngeal carcinoma (NPC) remains unclear, particularly in high-incidence areas.

METHODS

The authors conducted a population-based case-control study, consisting of 2514 incident NPC cases and 2586 randomly selected population controls, in southern China from 2010 to 2014. Occupational history and other covariates were self-reported using a questionnaire. Multivariate logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the risk of NPC associated with occupational exposures. Restricted cubic splines were used to evaluate potentially nonlinear duration-response relations.

RESULTS

Individuals who had exposure to occupational dusts (OR, 1.45; 95% CI, 1.26-1.68), chemical vapors (OR, 1.37; 95% CI, 1.17-1.61), exhausts/smokes (OR, 1.42; 95% CI, 1.25-1.60), or acids/alkalis (OR, 1.56; 95% CI, 1.30-1.89) in the workplace had an increased NPC risk compared with those who were unexposed. Risk estimates for all 4 categories of occupational exposures appeared to linearly increase with increasing duration. Within these categories, occupational exposure to 14 subtypes of agents conferred significantly higher risks of NPC, with ORs ranging from 1.30 to 2.29, including dust from metals, textiles, cement, or coal; vapor from formaldehyde, organic solvents, or dyes; exhaust or smoke from diesel, firewood, asphalt/tar, vehicles, or welding; and sulfuric acid, hydrochloric acid, nitric acid, and concentrated alkali/ammonia.

CONCLUSIONS

Occupational exposures to dusts, chemical vapors, exhausts/smokes, or acids/alkalis are associated with an excess risk of NPC. If the current results are causal, then the amelioration of workplace conditions might alleviate the burden of NPC in endemic areas.

LAY SUMMARY

The role of occupational exposures in the development of nasopharyngeal carcinoma (NPC) remains unclear, particularly in high-incidence areas. The authors conducted a population-based study with 2514 incident NPC cases and 2586 population controls in southern China and observed that occupational exposures were associated with an increased risk of NPC. Duration-response trends were observed with increasing duration of exposure. These findings provide new evidence supporting an etiologic role of occupational exposures for NPC in a high-incidence region.

Treatment and outcomes of nasopharyngeal carcinoma in a unique non-endemic population

OBJECTIVE

Nasopharyngeal carcinoma (NPC) is common in Southeast Asia. Due to the influx of immigrants from this region, the incidence in British Columbia is increasing. Current literature from non-endemic populations encompasses heterogeneous cohorts. This study examines NPC in a North American population, with a high incidence, to understand the population's characteristics, treatment outcomes and recurrence patterns.

METHODS AND MATERIALS

A retrospective analysis of patients treated for primary and recurrent NPC over 15-years. Regression analyses were used to identify predictors of disease recurrence and death. A subgroup analysis of the locoregional recurrence cohort was conducted. Five-year survival outcomes were determined.

RESULTS

601 patients were included. Asian ethnicity comprised 77% and the majority had non-keratinizing carcinoma (81%). In total, 19.3% of patients experienced recurrence: 58% local, 22% regional and 20% distant. Five-year overall survival was 70%. Smoking, advancing T-stage, poorer performance status and advanced overall stage were all associated with worse overall survival (p < 0.05). Asian ethnicity improved overall survival but not recurrence free survival. Similar features in addition to non-keratinizing histology were associated with increased locoregional recurrence (p < 0.05). Competing risk analysis indicated radiotherapy alone had a higher recurrence relative to chemoradiotherapy (HR 1.91, CI 1.17-3.09, p = 0.01).

CONCLUSIONS

We report the largest study evaluating treatment and outcomes of NPC in a non-endemic population. This unique population falls between described endemic and non-endemic populations. Non-keratinizing pathology and primary radiotherapy did not affect survival; however, both had a propensity for recurrence. Finally, patients experienced more locoregional and less distant recurrence, supporting that this cohort may be amenable to curative salvage therapy.

A Comprehensive Analysis of Treatment Management and Survival Outcomes in Nasopharyngeal Carcinoma

OBJECTIVES

To comprehensively investigate nasopharyngeal carcinoma (NPC) treatment, overall survival (OS), and the influence of clinical/sociodemographic factors on outcome.

STUDY DESIGN

Retrospective database study.

SETTING

National Cancer Database.

METHODS

The 2004-2015 National Cancer Database was queried for all patients with NPC receiving definitive treatment. Log-rank tests and Cox proportional hazards models were used for statistical analyses.

RESULTS

A total of 8260 patients with NPC were included (71.4% male; 42.5% with keratinizing histology; mean ± SD age, 52.1 ± 15.1 years), with a 5-year OS of 63.4%. Multivariate predictors of mortality included age ≥65 years (hazard ratio [HR], 1.81; P < .001), Charlson/Deyo score ≥1 (HR, 1.27; P = .001), American Joint Committee on Cancer clinical stage III to IV (HR, 1.85; P < .001), and government insurance or no insurance (HR, 1.53; P < .001). Predictors of survival included female sex (HR, 0.82; P = .002), Asian/Pacific Islander race (HR, 0.74; P < .001), nonkeratinizing/undifferentiated histology (HR, 0.79; P = .004), and receiving treatment at academic centers (HR, 0.87; P = .02). Chemoradiotherapy (CRT) demonstrated improved OS as compared with radiotherapy (RT) only for stage II (P = .006) and stage III (P = .005) and with RT or chemotherapy only in stage IVA NPC (P < .001). When compared with CRT alone, surgery plus CRT provided OS benefits in keratinizing (P = .013) or stage IVA (P = .030) NPC. When compared with RT, CRT provided OS benefits in keratinizing (P = .005) but not nonkeratinizing (P = .240) or undifferentiated (P = .390) NPC. Substandard radiation dosing of <60 Gy and <30 fractions were associated with inferior OS (both P < .001).

CONCLUSIONS

NPC survival is dependent on a variety of clinical/sociodemographic factors. Stage-specific treatments with optimal OS include CRT or RT for stages I to II and CRT for stage III to IV. The large representation of nonendemic histology is valuable, as these cases are not well characterized.

Epstein-Barr Virus Mediated Signaling in Nasopharyngeal Carcinoma Carcinogenesis

Simple Summary

Epstein-Barr virus (EBV) infection is known to contribute in nasopharyngeal carcinoma (NPC) carcinogenesis. The oncogenic roles of the EBV proteins and non-coding RNAs in NPC are becoming evident with the aid of current advances in genome-wide and in-depth molecular analyses. This current work provides a comprehensive overview, which covers recent understandings of the pathogenic role of EBV infection in NPC. Perspectives on molecular mechanisms, which are involved in the pathogenesis of NPC, focusing on the connection between EBV and NPC cells and the corresponding signaling pathways are highlighted. Cancer hallmarks associated with EBV in NPC development are also discussed herein.

Abstract

Nasopharyngeal carcinoma (NPC) is one of the most common tumors occurring in China and Southeast Asia. Etiology of NPC seems to be complex and involves many determinants, one of which is Epstein-Barr virus (EBV) infection. Although evidence demonstrates that EBV infection plays a key role in NPC carcinogenesis, the exact relationship between EBV and dysregulation of signaling pathways in NPC needs to be clarified. This review focuses on the interplay between EBV and NPC cells and the corresponding signaling pathways, which are modulated by EBV oncoproteins and non-coding RNAs. These altered signaling pathways could be critical for the initiation and progression of NPC.

Epstein-Barr virus and human papillomavirus serum antibodies define the viral status of nasopharyngeal carcinoma in a low endemic country

Epstein-Barr virus (EBV) causes nasopharyngeal carcinoma (NPC) in endemic regions, where almost every tumor is EBV-positive. In Western populations, NPC is rare, and human papillomavirus infection (HPV) has been suggested as another viral cause. We validated multiplex serology with molecular tumor markers, to define EBV-positive, HPV-positive and EBV-/HPV-negative NPCs in the United Kingdom, and analyzed survival differences between those groups. Sera from NPC cases (n = 98) and age- and sex-matched controls (n = 142) from the Head and Neck 5000 clinical cohort study were analyzed. IgA and IgG serum antibodies against 13 EBV antigens were measured and compared with EBER in situ hybridization (EBER-ISH) data of 41 NPC tumors (29 EBER-ISH positive, 12 negative). IgG antibodies to EBV LF2 correctly diagnosed EBV-positive NPCs in 28 of 29 cases, while all EBER-ISH negative NPCs were seronegative to LF2 IgG (specificity = 100%, sensitivity = 97%). HPV early antigen serology was compared to HPV molecular markers (p16 expression, HPV DNA and RNA) available for 41 NPCs (13 positive, 28 negative). Serology matched molecular HPV markers in all but one case (specificity = 100%, sensitivity = 92%). EBV and HPV infections were mutually exclusive. Overall, 67% of the analyzed NPCs were defined as EBV-positive, 18% as HPV-positive and 14% as EBV/HPV-negative. There was no statistical evidence of a difference in survival between the three groups. These data provide evidence that both, EBV-positive and HPV-positive NPCs are present in a low incidence country, and that EBV and HPV serum antibodies correlate with the viral status of the tumor.

Multiple low-frequency and rare HLA-B allelic variants are associated with reduced risk in 1,105 nasopharyngeal carcinoma patients in Hunan province, southern China

In our study, 1,105 cases of nasopharyngeal carcinoma (NPC) and 1,430 normal controls recruited from Hunan province, southern China were typed for human leukocyte antigen (HLA)-B locus by Sanger sequencing exons 2-4. Besides confirming the NPC association with HLA-B*46:01 allele, HLA-A*02:07-B*46:01 and HLA-A*33:03-B*58:01 haplotypes (all positive), and HLA-B*13 lineage (negative), all of which were relatively common, strong negative associations were observed for five low-frequency and rare alleles or lineages, including HLA-B*07, -B*27:04, -B*39, -B*51:02 and -B*55:02, with odds ratio (OR) ranging from 0.16 to 0.3 (all p_corrected < 0.05). These strong protective associations were independent of linkage disequilibrium (LD) between HLA-A and HLA-B loci. Further analysis indicated a single amino acid change from histidine to tyrosine at residue 171 is probably crucial for the mutant allele, HLA-B*51:02, to mediate resistance to NPC. A subset of NPC cases (n = 821) and normal controls (n = 1,035) were tested for antivirus capsid antigen immunoglobulin A (anti-VCA IgA), which differed drastically between the two groups [67.7% vs. 5.5%, OR (95% confidence interval) = 36 (26.55-48.81), p < 0.0001]. HLA-B allelic variation did not associate with seropositivity for anti-VCA IgA in either group. Results from our study show, more clearly than previously, the existence of a cluster of low-frequency and rare HLA-B variants conferring low, or very low risk to NPC, a phenomenon not observed in other ethnic groups. Our data shed new insights into genetic susceptibility to NPC in southern Chinese populations. Future independent studies are warranted to replicate the findings reported in our study.

MiR-214 Mediates Cell Proliferation and Apoptosis of Nasopharyngeal Carcinoma Through Targeting Both WWOX and PTEN

Background: This study aimed to investigate interactions between miR-214, PTEN, and WWOX and their effect on AKT signaling during the NPC progression. Nasopharyngeal carcinoma (NPC) was highly prevalent with poor prognosis among the patients. MiR-214 reported as an important NPC biomarker was associated with regulation of biological functions.

Methods: 5–8F and 6–10B NPC cells were transfected with miR-214 inhibitor. MTT and colony formation assays were performed to assess cell proliferation. PI staining assay was performed to determine distribution of cell cycle. Annexin-V/PI staining assay was used to evaluate cell apoptosis in NPC. The effects of miR-214 inhibitor on the expression levels of PTEN, WWOX, AKT signaling pathway, cell-cycle-, and apoptosis-associated proteins were assessed by Western blotting or qRT-PCR assay. PTEN and WWOX were knocked down using the corresponding shRNA to investigate their effects on miR-214 inhibitor involved in proapoptosis and antiproliferation mechanisms in NPC.

Results: Inhibition of miR-214 suppressed cell growth and induced apoptosis of 5–8F and 6–10B cells. MiR-214 regulated the expression of both PTEN and WWOX through targeting the 3′-UTR. Inhibition of miR-214 promoted WWOX and PTEN expression, inactivated AKT signaling pathway, and regulated cell-cycle- and apoptosis-associated proteins. Knockdown of PTEN or WWOX reversed effects of miR-214 inhibitor on AKT signaling, cell proliferation, and apoptosis.

Conclusion: MiR-214 was suggested to induce cell proliferation and inhibit cell apoptosis of NPC through directly targeting both PTEN and WWOX, which provided a novel therapeutic target for clinical treatment of NPC.

Smokeless Tobacco Use, Cigarette Smoking, and Upper Aerodigestive Tract Cancers: A Case-Control Study in the Batna Region, Algeria, 2008-2011

BACKGROUND

A significant proportion of the Algerian population uses tobacco products and is at risk of developing tobacco-associated cancers.

AIMS

This case-control study reports on the association between tobacco use and the occurrence of upper aerodigestive tract (UADT) cancers in Batna, Algeria.

METHODS

Incident primary UADT cancer cases in residents of Batna in 2008-2011 were identified using the regional tumor registry. One hospital and 1 population control were matched to each case by sex, year of birth, and residence. Information on tobacco use was collected, and odds ratios (ORs) were obtained using conditional logistic regression also after sex stratification.

RESULTS

The study included 192 cases (80%) of the 241 primary UADT cancer cases identified and 384 controls. Males represented 76.6% of cancer cases. Cancers of the nasopharynx (48%) and the larynx (26%) were the most common types. Ever use of smokeless tobacco (ST) (OR = 1.0; 95% confidence interval [CI]: 0.6-1.5) or current ST use (OR = 1.1; 95% CI: 0.6-1.7) was not associated with overall risk of UADT cancers. Associations with cancers of the nasopharynx (OR = 1.5; 95% CI: 0.5-4.6) and oral cavity/oropharynx (OR = 3.0; 95% CI: 0.8-11.8) were found when comparing use of ST only to no consumption of any tobacco. Cigarette smoking was associated with an increase in the overall risk of UADT cancers, with a 3-fold increase in the risk of laryngeal cancer when comparing smoking only to no consumption of any tobacco (OR = 3.3; 95% CI: 1.0-11.5). Associations for smokers who also consumed ST differed by cancer site.

CONCLUSION

In this study from Algeria dominated by male cases and by cancer in the nasopharynx, cigarette smoking but not ST was associated with UADT cancer. Analyses by anatomical site and using as reference never use of any type of tobacco suggested few associations with ST but of lower precision.

Cigarette smoking increases the risk of nasopharyngeal carcinoma through the elevated level of IgA antibody against Epstein-Barr virus capsid antigen: A mediation analysis

Background

The study aims are to evaluate the associations between nasopharyngeal carcinoma (NPC) risk and cigarette smoking and to explore the effects of cigarette smoking on Epstein‐Barr virus (EBV) infection for NPC risk.

Methods

1235 male NPC cases and 1262 hospital‐based male controls matched to cases were recruited across six collaborative hospitals between 2010 and 2014. Using a standardized questionnaire, information on cigarette smoking and other potential risk factors for NPC was obtained. Blood was collected and used for anti‐EBV VCA IgA and anti‐EBV EA‐EBNA1 IgA testing using standard methods. Unconditional logistic regression analysis was used to estimate odds ratio (OR) with 95% confidence interval (CI) for each risk factor after adjusting for confounders.

Results

63.6% of cases and 44.0% of controls reported ever smoking cigarettes. After full adjustment, current smokers had a significant 1.60‐fold (95% CI = 1.30‐1.97) and former smokers a borderline significant 1.27‐fold (95% CI = 1.00‐1.60) increased NPC risk compared to never smokers. NPC risk increased with increasing duration, intensity, and pack‐years of cigarette smoking but not with age at smoking initiation. Among controls, anti‐EBV VCA IgA seropositivity rate was higher in current smokers than never smokers (14.0% vs 8.4%; OR = 1.82; 95% CI = 1.19‐2.79). Mediation analyses showed that more than 90% of the cigarette smoking effect on NPC risk is mediated through anti‐EBV VCA IgA.

Conclusion

This study confirms the association between long‐term cigarette smoking and NPC and demonstrates that current smoking is associated with seropositivity of anti‐EBV VCA IgA antibodies.

Nasopharyngeal Carcinoma (NPC) Risk Factors: A Systematic Review and Meta-Analysis of the Association with Lifestyle, Diets, Socioeconomic and Sociodemographic in Asian Region

Objective:

Risk factors of nasopharyngeal carcinoma (NPC) have been linked with diets, life style and viral infections. NPC is more rampant in Asian populations than non-Asian countries. Our study aims to assess the validity of the suggestions provided by multiple case control studies demonstrating that salted fish consumption, smoking and alcohol consumption are associated with the risk of NPC in Asia.

Methods:

Search for related literature on salted fish, smoking and alcohol consumption were performed via Science Direct, PubMed databases and Google Scholar. Articles included in this study were from 2009 to 2017, with specific focus on salted fish, smoking and alcohol consumption as risk factors of NPC. This study excluded all articles published prior to 2009 and articles involving other cancers. Data were extracted independently by two different researchers and harmonized. Meta-analysis was conducted on the obtained data, by using R package Meta to create funnel and forest plots.

Results:

The meta-analysis revealed that salted fish, smoking and alcohol consumption were significantly associated to NPC risk with random effect model score showing OR of 1.41 at 95% confidence interval (CI) of 1.13-1.75 (P<0.01), OR of 1.89 at 95 % CI of 1.49 – 2.38, and OR: 1.42 at 95 % CI of 1.23 – 1.65 respectively. Our results also revealed significant association of salted meat, salted vegetables, house type, wood dust exposure associated with NPC risk with p values less than 0.05.

Conclusion:

This study proposes that salted fish intake, smoking and alcohol consumption might be linked to NPC risk in Asians. Further studies are necessary to ascertain the molecular mechanisms and clarify if the associated path that could function as therapeutic target.

Association Between Serum Cotinine Level and Serological Markers of Epstein-Barr Virus in Healthy Subjects in South China Where Nasopharyngeal Carcinoma Is Endemic

Introduction: Self-reported smoking has been associated with higher seropositivity for the IgA response to Epstein–Barr virus (EBV) viral capsid antigen (VCA-IgA) and transcription activator protein (Zta) in healthy men in southern China where nasopharyngeal carcinoma (NPC) is endemic. Results on the association of biochemically verified smoking status with EBV reactivation are scarce. We aimed to investigate the relations of serum cotinine level with serological markers of EBV in healthy women, in addition to men.

Methods: We collected information on demographic, lifestyle, environmental factors, and EBV serological markers in a cross-sectional study on 2,275 healthy subjects who were recruited from physical examination centers in Guangdong Province, China. In the present analysis, 901 subjects' serum cotinine levels have been measured by enzyme-linked immunosorbent assay (ELISA). Odds ratios (seropositivity of four EBV serological markers vs. seronegativity) for categorical serum cotinine levels were calculated by unconditional logistic regression with a group-specific confidence interval (CI).

Results: In women, compared with lower serum cotinine level (0–0.71 ng/ml), higher cotinine level (>0.71–1.20 ng/ml; >1.20–228.40 ng/ml) was associated but non-significantly with higher seropositivity for EBV VCA-IgA (age- and education-adjusted OR = 1.18, 95% CIs = 0.84–1.64, 1.06, 0.75–1.50). These associations remained but still non-significant after adjusting for 5-year age group, education, family history of cancer, consumption of tea, Chinese herbal tea, salted fish at childhood, and exposure to occupational dust, chemical, fume, and radiation (multivariable adjusted OR = 1.21, 95% CIs = 0.85–1.71, 1.09, 0.76–1.55). In men, compared with lower serum cotinine level (0–2.15 ng/ml), higher cotinine level (>2.15–103.6 ng/ml; >103.6–419.4 ng/ml) was significantly associated with higher seropositivity for EBV VCA-IgA and Zta-IgA (age- and education-adjusted OR = 2.16, 95% CIs = 1.37–3.41, 1.79, 1.11–2.90; 1.98, 1.17–3.34, 1.95, 1.14–3.34). The association remained significant after adjusting for potential confounders for Zta-IgA (OR = 2.32, 95% CI = 1.37–3.93 for >2.15–103.6, and 2.50, 1.43–4.38 for >103.6–419.4 ng/ml), but not for VCA-IgA (2.06, 1.29–3.27, and 1.61, 0.96–2.71).

Conclusions: Higher serum cotinine level is associated with higher seropositivity for EBV serological markers in healthy men in southern China. Such positive association was also observed in women but became non-significant. If confirmed to be causal, this finding has important implications for tobacco control and prevention of EBV-related disease, particularly for NPC.

Past and Recent Salted Fish and Preserved Food Intakes Are Weakly Associated with Nasopharyngeal Carcinoma Risk in Adults in Southern China

BACKGROUND

Chinese-style salted fish intake in early life is considered an established risk factor for nasopharyngeal carcinoma (NPC). However, results for adult intakes of salted fish and preserved foods are inconsistent.

OBJECTIVE

The aim of this study was to ascertain the relations of Chinese-style hard and soft salted fish and preserved food intakes with NPC risk.

METHODS

We conducted a population-based case-control study in southern China with 2554 NPC cases identified through a rapid case ascertainment system and 2648 healthy controls, frequency-matched on age, sex, and area. Subjects (aged 20-74 y) were interviewed via a food-frequency questionnaire, including information on portion size. Data were also collected on alcohol consumption and potential confounders. Food intake was grouped into 3-5 energy-adjusted intake levels during adulthood (10 y prior) and adolescence (16-18 y). For childhood (at age 10 y), intake frequency of selected food items was collected. Multivariate-adjusted ORs with 95% CIs were estimated via logistic regression.

RESULTS

We found no association between NPC and intake of hard Chinese-style salted fish during adulthood, and an increased risk at the highest level of intake during adolescence (OR: 1.19; 95% CI: 1.03, 1.39). In contrast, we found a decreased risk for the middle intake level of soft salted fish during adulthood (OR: 0.68; 95% CI: 0.57, 0.81) and adolescence (OR: 0.71; 95% CI: 0.59, 0.85). Preserved foods showed contrasting risk profiles, e.g., the highest adult intake level of salted egg (OR: 1.51; 95% CI: 1.22, 1.87) and fermented black beans (OR: 0.67; 95% CI: 0.56, 0.80). Associations with NPC were weaker than previously reported, e.g., for weekly childhood intake of salted fish (OR: 1.56; 95% CI: 1.24, 1.97).

CONCLUSIONS

Hard and soft salted fish have different risk profiles. Salted fish and other preserved foods were at most weak risk factors for NPC in all periods and may play a smaller role in NPC occurrence than previously thought.

Tissue P16 is Associated with Smoking Status among Indonesian Nasopharyngeal Carcinoma Subjects

Background: Nasopharyngeal carcinoma (NPC) is a malignancy with high incidence in Southern China and South-East Asia. NPC incidence among males in Indonesia is estimated around 8.3/100,000 populations. Tobacco smoking is a common risk factor for cancer, including NPC. P16 is one of the key proteins related to the activation of apoptotic pathways, that commonly change during carcinogenesis. Carcinogenesis is often related to environmental exposure, including tobacco smoke. Objective: To analyze the association between P16 protein and smoking status among NPC subjects in Indonesia. Methods: Forty formalin fixed-paraffin embedded NPC tissue samples of known smoking status (20 smokers, 20 non-smokers) were collected from the Department of Anatomical Pathology, Dr. Sardjito Hospital, Yogyakarta. P16 was detected by immunohistochemistry staining. German semi-quantitative scoring system was applied to the P16 staining. Expression index with the score of 0 to 3 was classified as negative staining, meanwhile 4 to 12 was classified as positive staining. The association between P16 (score) and smoking status among NPC patients was analyzed using Fischer exact test. One-sided p ≤ 0.05 was considered as statistically significant. Results: All samples were Javanese males, with age range 25-76 years old. P16 positive staining among smokers was 5% (1/20), while among non-smokers was 40% (8/20). P16 among smokers was significantly lower than non-smokers patients (p=0.010). No difference was found between quantity of smoke and P16 score. Conclusion : A significant association between P16 and smoking status in Indonesian NPC patients has been revealed. The result of this study may be used to improve prevention and management of NPC cases related to smoking habit in Indonesia.

Associations between environmental factors and serological Epstein-Barr virus antibodies in patients with nasopharyngeal carcinoma in South China

Epstein‐Barr virus (EBV) reactivation, reflected by aberrantly increased levels of various serological antibodies, has been suggested to be an early indicator of nasopharyngeal carcinoma (NPC) onset and progression. We have previously suggested that certain lifestyle and dietary factors were associated with elevated serological levels of the antibody against various EBV antigens namely VCA, Zta, EBNA1, and oral EBV DNA loads among healthy population. It remains unclear whether these potential environmental factors would also influence EBV serological antibodies in NPC patients. We conducted an epidemiological study to evaluate the associations between such environmental factors and EBV antibody levels among 1701 NPC patients in South China. Pretreatment serums were collected and examined for VCA‐IgA and EA‐IgA by immunoenzymatic assays and antienzyme rate (AER) of EBV DNase‐specific neutralizing antibody. We found that consumption of Canton‐style herbal tea was significantly correlated with increased serological antibody levels of VCA‐IgA and EA‐IgA, with adjusted ORs of 1.35 (95% CI: 1.03‐1.76) and 1.32 (95% CI: 1.01‐1.73), respectively, in the weekly intake frequency stratum, while not related to AER of EBV DNase‐specific neutralizing antibody. Smoking was found to be not only an apparent risk factor for higher antibody levels of AER in stage III‐IV patients (OR = 1.60, 95% CI: 1.11‐2.30), but also associated closely with NPC stage at diagnosis (OR = 2.17, 95% CI: 1.47‐3.22), with dose‐response effects. In conclusion, we found consumption of Canton‐style herbal tea and cigarette smoking were in positive associations with elevated EBV antibodies in NPC patients, which may be of public health significance for the primary prevention of EBV‐associated diseases especially NPC.

Does East meet West? Towards a unified vision of the management of Nasopharyngeal carcinoma

Nasopharyngeal cancer (NPC) is notable for its wide geographic variation, with incidences as high as 30 in 100,000 in endemic regions but < 1 in 100,000 worldwide. This review aims to identify areas where there could be differences in prognosis, management or outcomes among countries with high or low incidence of NPC. The incidence has generally declined both in endemic and non-endemic regions throughout the years, which may be attributed to the decrease in exposure to risk factors such as early exposure to salted fish and smoking. Ethnicity has an impact both on incidence and prognosis, with Southeast Asians having the highest incidence but also better survival. Concurrent chemoradiotherapy, with or without adjuvant and/or induction chemotherapy, is the standard of care for locoregionally advanced disease, as reflected in clinical practice guidelines. Despite improvements in management, a proportion of patients relapse. Salvage treatment is associated with significant morbidity due to the critical location of the nasopharynx and the toxicities of initial therapy. Clinical expertise is paramount, but is easier to attain in endemic regions and high volume centers where enrollment of patients in clinical trials is more feasible. Collaboration between low and high incidence countries and between low and high volume facilities is key to improving NPC prognosis worldwide.

[Contribution of concomitant radiochemotherapy in the management of undifferentiated carcinoma of the nasopharynx in adults]

L'objectif de l'étude et d'Analyser les caractéristiques épidémiologiques, cliniques, thérapeutiques et évolutives du carcinome indifférencié du nasopharynx de l'adulte. Il s'agit d'une étude cohorte rétrospective portant sur 163 patients âgés de 17 ans et plus, traités pour un carcinome indifférencié du nasopharynx non métastatique. L'âge moyen des patients était de 46,5ans, avec un sexe-ratio de 1,7. 35,57% des patients étaient atteints de tumeurs localement évoluées (T3-T4) et 52,27% avec une atteinte ganglionnaire régionale avancée (N2-N3). Sur le plan thérapeutique une chimiothérapie neoadjuvante a été réalisée chez 77% des patients et 93,8% des patients ont bénéficié d'une radio-chimiothérapie concomitante. Après un recul moyen de 40,8 mois la survie globale était de 92,9% et la survie sans récidive (SSR) était de 78,9%. L'analyse de la survie sans récidive SSR en fonction des différents facteurs pronostiques a montré une différence statistiquement significative pour l'atteint ganglionnaire avec des taux de SSR à trois ans de 88%, 82,6%, 80,8% et 61,5% en cas de tumeur classée N0, N1, N2 et N3 respectivement (p = 0,02). Le cancer du nasopharynx est une maladie complexe, mais des progrès ont été accomplis grâce à des percées en radiothérapie et en biologie moléculaire. La radio-chimiothérapie concomitante représente le standard thérapeutique des stades cliniques supérieur ou égal à T2, ou supérieur ou égal à N1. Les techniques innovantes d'irradiation semblent prometteuses et pourraient pallier aux problèmes de toxicité tardive tout en assurant un excellent taux de contrôle local.

Occupational exposure to wood dust and risk of nasopharyngeal cancer: A systematic review and meta-analysis

INTRODUCTION

Nasopharyngeal cancer (NPC) is one of the most commonly occurring cancers in some regions. While wood dust is a confirmed human carcinogen, its association with NPC remains uncertain due to inconsistent findings in the related studies. We performed the first systematic review and meta-analysis on the epidemiological evidence to examine the association between occupational exposure to wood dust and the risk of NPC.

METHODS

In this meta-analysis study, the PubMed and Scopus databases were searched for English-language publications. seven case-control studies were included in the pooled analysis.

RESULTS

These studies were published between 1991 and 2016. The heterogeneity across the studies was significant (P = 0.06, I² = 50.4%). The results of the random effects model meta-analysis showed that there was a direct relationship between occupational exposure to wood dust and NPC (OR = 1.5 95% CI: 1.09-2.07). Among different histological subtypes of NPC, there was a significantly increased risk for the nonkeratinizing carcinoma following wood dust exposure (OR = 1.68, 95%CI: 1.03-2.74). We found no evidence of publication bias across studies according to the result of the Egger's test (P of bias = 0.073).

CONCLUSIONS

This meta-analysis suggests that occupational exposure to wood dust can be associated with an increased risk of the nonkeratinizing carcinoma of the histological subtypes of nasopharyngeal cancer.

Disparities in impact of nasopharyngeal cancer: An analysis of global health burden

OBJECTIVES

Nasopharyngeal carcinoma has a unique worldwide racial and geographic distribution. Our objective was to evaluate socioeconomic disparities in the burden of nasopharyngeal cancer (NPC) between endemic and nonendemic regions.

METHODS

To demonstrate trends regarding societal burden of NPC and socioeconomic development, national disability-adjusted life year (DALY) rates and human development indices (HDI) between 1990 and 2015 were evaluated. Countries were divided based on the endemic versus nonendemic presence of NPC and further analyzed by HDI status as specified by the United Nations Development Program. Gini coefficients and concentration index were used to evaluate global equality in NPC burden over this period.

RESULTS

Age-standardized DALYs dropped from 36.1 in 1990 to 26.5 in 2015 (26.6% decline) (r = -0.991, P < 0.001). Lower socioeconomic countries harbored greater NPC burden upon controlling by endemic and nonendemic regions, as demonstrated by progressively negative concentration indexes. Health inequality was greater in nonendemic countries than in endemic countries (P < 0.01).

CONCLUSION

To our knowledge, this is the first study to investigate socioeconomic-related changes in NPC burden using statistical tools such as the Gini coefficient and concentration index. Although the burden of NPC has steadily decreased, there remain persistent inequalities associated with socioeconomic disparities. Nasopharyngeal cancer burden is more pronounced in countries with lower HDI. Our results reinforce the importance of increasing resources for developing countries and continuing inquiry into the screening, diagnosis, and management of NPC.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:2482-2486, 2019.

Smoking can increase nasopharyngeal carcinoma risk by repeatedly reactivating Epstein-Barr Virus: An analysis of a prospective study in southern China

Background

The association between smoking and nasopharyngeal carcinoma (NPC) is still uncertain. The aim of this study was to validate smoking effect on NPC and explore if smoking can induce NPC by persistently reactivating EBV in long‐term based on a prospective cohort design.

Methods

A NPC screening cohort with 10 181 eligible residents in Sihui city, southern China was conducted from 2008 to 2015. The smoking habit was investigated through the trained interviewers and EBV antibodies (VCA‐IgA, EBNA1‐IgA) as screening markers were tested periodically. New NPC cases were identified through local cancer registry. Cox's regression model was used to estimate the adjusted hazard ratios (aHRs) of smoking on NPC incidence. In the non‐NPC participants, the associations between smoking and EBV seropositivity in different periods were assessed by logistic regression and generalized estimating equations (GEE).

Results

With a median of 7.54 years, 71 NPCs were diagnosed ≥1 year after recruitment. Compared with never smokers, the aHRs of developing NPC among ever smokers were 3.00 (95%CI: 1.46‐6.16). Stratified by sex, the HRs of ever smoking were 2.59 (95%CI: 1.07‐6.23) for male and 3.75 (95%CI: 1.25‐11.20) for female, respectively. Among the non‐NPC individuals, ever smoking was not only associated with EBV seropositivity at baseline, but also in the 3‐5 years of follow up, with adjusted odds ratios (aORs) of 1.68 (95%CI: 1.29‐2.18) for VCA‐IgA and 1.92 (95%CI: 1.42‐2.59) for EBNA1‐IgA. Among the smokers who were tested EBV antibodies at least twice, the similar results were obtained using GEE.

Conclusion

Smoking could significantly increase the long‐term risk of NPC in southern China, partly by persistently reactivating EBV.

Adherence to Mediterranean diet: A comparison of patients with head and neck cancer and healthy population

BACKGROUND AND OBJECTIVE

The traditional Mediterranean diet (MD) is associated to a lower risk of suffering multiple tumors. However, few studies have analyzed the relationship between MD and the risk of developing head and neck cancer (HNC). A case-control study comparing adherence to MD was conducted in patients diagnosed with HNC and healthy population.

PATIENTS AND METHODS

The level of adherence to MD was assessed using the 14-item MEDAS (Mediterranean Diet Adherence Screener) questionnaire, used in the PREDIMED study, in patients diagnosed with HNC at 12de Octubre Hospital in Madrid (cases) and in healthy subjects enrolled in a nearby primary health care center (controls). Adherence was stratified based on the score as low (≤7points), medium (8-9points), and high (≥10points). The odds ratio (OR) for developing HNC was estimated based on different factors.

RESULTS

A sample of 168 subjects (100 controls and 68 cases) was analyzed. Smoking (OR, 2.98 [95%CI: 1.44-6.12]; P=.003) and alcohol consumption (OR, 2.72 [95%CI: 1.39-5.33], P=.003) were strongly associated to HNC. However, medium-high adherence to MD was associated to a lower risk of developing HNC (OR, 0.48 [95%CI: 0.20-1.07], P=.052).

CONCLUSIONS

Consistent medium-high adherence to MD contributes to decrease the risk of developing HNC.

Fine-mapping of HLA class I and class II genes identified two independent novel variants associated with nasopharyngeal carcinoma susceptibility

BACKGROUND

Several genome-wide association studies (GWASs) have identified strong associations between genetic variants in the human leukocyte antigen (HLA) region and nasopharyngeal carcinoma (NPC). However, given the complex LD pattern in this region, the causal variants and the underlying mechanism of how genetic variants in HLA contribute to NPC development is yet to be understood.

METHODS

To systematically characterize the HLA variants and their relationship to NPC susceptibility, we fine-mapped the HLA genes based on the GWAS data of 1583 NPC cases and 972 healthy controls, using SNP2HLA with the Pan-Asian panel as references. Stepwise conditional regression was used to identify independent association loci.

RESULTS

Interestingly, the most significant association was the presence of Gln in HLA-A amino acid position 62 (OR = 0.57, P = 1.41 × 10^-16 ). The G allele of rs2894207 located between HLA-B and HLA-C showed protective effect of NPC development (OR = 0.52, P = 2.23 × 10^-13 ). Additionally, amino acid Phe-67 located in the peptide-binding pocket of HLA-DRB1 was identified as a novel functional variant with OR = 0.64 and P = 9.64 × 10^-11 . Another novel variant, Glu-45 in HLA-B pocket B, conferred a protective effect on NPC susceptibility (OR = 0.64, P = 5.23 × 10^-8 ). These four variants explained 2.07% of the phenotypic variance for NPC risk.

CONCLUSION

In summary, by fine-mapping the HLA region in south Chinese population, we reported additional loci missed in the GWAS studies and provided a better understanding of the relationship between HLA and NPC susceptibility.

Impact of age on survival of locoregional nasopharyngeal carcinoma: An analysis of the Surveillance, Epidemiology, and End Results program database, 2004-2013

OBJECTIVES

To determine the impact of age at diagnosis and other factors on survival in nasopharyngeal carcinoma (NPC).

DESIGN, SETTING AND PARTICIPANTS

A retrospective, population-based cohort study of 3103 patients are selected, whose records were submitted to the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2013. We evaluated the demographic and clinical characteristics of patients who were 20 years or older with a diagnosis of primary, non-metastatic NPC.

MAIN OUTCOME MEASURES

Overall survival (OS) and risks of OS and NPC-specific survival.

RESULTS

Overall survival rates at 1, 3, and 5 years were 85.8%, 71.0%, and 62.6%, respectively. Older age was a significant predictor of poor OS, as was Chinese ethnicity. We also determined that middle-aged white patients, but not middle-aged black or Chinese patients, were at a higher risk of death than were younger patients of the same race/ethnicity. Nodal (N) stage 0-1 disease was a significant predictor of poor OS when comparing survival of older patients with N0-1 vs N2-3 stage disease. Finally, we found that married patients had a decreased risk of death when compared to those who were single.

CONCLUSIONS

The survival of older patients with NPC is inferior to that of younger patients. Race/ethnicity, marital status, and stage of disease are important modifiers of risk. Collectively, our results indicate that management of older patients requires optimisation.

The contribution of interleukin-8 genotypes and expression to nasopharyngeal cancer susceptibility in Taiwan

The incidence rate of nasopharyngeal cancer (nasopharyngeal carcinoma [NPC]) is much higher in Southeast Asia than in western countries. Interleukin-8 (IL-8), a chemokine produced by macrophages, epithelial cells, airway smooth muscle cells, and endothelial cells, is an important immuno-mediator in the development and progression of many types of cancer. Genetic variations in IL-8 have been associated with the risks of NPC and other cancers. In the current study, we evaluated the role of IL-8 in NPC at the levels of DNA, RNA, and protein in a Taiwanese population. First, in a case-control study, 176 NPC patients and 352 cancer-free controls were genotyped, and the associations of IL-8 T - 251A, C + 781T, C + 1633T, and A + 2767T polymorphisms with NPC risk were evaluated. Second, the NPC tissue samples were assessed for their IL-8 mRNA and protein expression by real-time quantitative reverse transcription polymerase chain reaction (PCR) and Western blotting, respectively. Regarding the IL-8 promoter T - 251A, the TA and AA genotypes were associated with significantly decreased risks of NPC compared with the wild-type TT genotype (adjusted odds ratio = 0.61 and 0.52, 95% confidence interval = 0.47-0.93 and 0.37-0.91, P = .0415 and .0289, respectively). The mRNA and protein expression levels for NPC tissues revealed no significant associations among the 20 NPC samples with different genotypes. These findings suggest that IL-8 may play an important role in the carcinogenesis of NPC in Taiwan.

Diagnostic potential of methylated DAPK in brushing samples of nasopharyngeal carcinoma

Background

The death-associated protein kinase (DAPK) gene is an important member of the apoptotic pathway and is inactivated by abnormal methylation in numerous cancers, including nasopharyngeal carcinoma (NPC). However, the diagnostic value of DAPK methylation in brushing samples and tissue samples of NPC remains unclear.

Methods

We conducted a systematic meta-analysis based on 17 studies (including 386 tissue cases, 233 brushing cases, and 296 blood cases).

Results

Our results revealed an association between methylated DAPK and increased risk of NPC in blood, brushing, and tissue samples. In addition, the comparison of the pooled sensitivity, specificity, and area under the curve of methylated DAPK in brushing and tissue samples demonstrated the non-inferior effectiveness of methylated DAPK in brushing samples to monitor the development of NPC.

Nasopharyngeal carcinoma: A review of current updates

Nasopharyngeal carcinoma (NPC) is a rare malignancy worldwide, but it is endemic in a few areas including Southern China, Southeast Asia, North Africa and the Arctic. The underlying mechanisms behind this remarkable geographic distribution remain unclear. Although Epstein-Barr virus (EBV) infection has been suggested as a necessary cause of undifferentiated NPC, EBV itself is not sufficient to cause this malignancy. Other co-factors, such as environmental risk factors, and/or genetic susceptibility, may interact with EBV to play a role in the carcinogenesis of NPC. Survival rates differ significantly between NPC patients in early stages and late stages. Due to the close associations between EBV infection and NPC risk, EBV-related biomarkers have been used for early detection and screening for NPC in a few high-incidence areas. In the present review article the latest updates are discussed.

Lack of association between cigarette smoking and Epstein Barr virus reactivation in the nasopharynx in people with elevated EBV IgA antibody titres

BACKGROUND

Subjects with elevated Epstein-Barr virus (EBV) immunoglobulin A (IgA) titers have a higher risk of developing nasopharyngeal carcinoma (NPC), indicating that reactivation of EBV in the local mucosa might be important for NPC carcinogenesis. Cigarette smoking appears to be one of the environmental risk factors for NPC. However, it remains unclear whether smoking-induced nasopharyngeal carcinogenesis acts through reactivating EBV in the nasopharyngeal mucosa. Therefore, this study aims to investigate the association between cigarette smoking and nasopharyngeal EBV reactivation in a NPC high-risk population.

METHODS

A NPC high-risk cohort study, established from a population-based NPC screening program of 22,816 subjects, consisted of 1045 subjects with elevated serum IgA antibodies against EBV viral capsid antigen (VCA/IgA). Among high-risk subjects, information on detailed cigarette smoking history was collected among 313 male subjects. The associations between cigarette smoking and EBV antibody levels, EBV DNA load of the nasopharynx were analyzed.

RESULTS

No significant association was observed between either nasopharyngeal EBV DNA load or serum VCA/IgA titers and smoking status, age at smoking initiation, daily smoking intensity, smoking duration, cigarette type, or pack-years of smoking. Cigarette smoking characteristics in all subgroups did not correlate with nasopharyngeal EBV DNA positivity or EBV VCA/IgA seropositivity.

CONCLUSIONS

In a population at high risk of NPC, our study suggests that cigarette smoking is neither associated with nasopharyngeal EBV DNA load nor serum VCA/IgA antibody level. Smoking-associated NPC carcinogenesis may act through other mechanisms than reactivating nasopharyngeal EBV replication.

Cigarette smoking and the risk of nasopharyngeal carcinoma: a meta-analysis of epidemiological studies

OBJECTIVE

The role of cigarette smoking as an independent risk factor for patients with nasopharyngeal carcinoma (NPC) is controversial. We attempted to provide evidence of a reliable association between cigarette smoking and the risk of NPC.

DESIGN

Meta-analysis.

DATA SOURCES

PubMed online and the Cochrane Library of relevant studies published up to February 2016.

ELIGIBILITY CRITERIA

All studies had to evaluate the relationship between NPC and cigarette smoking with never smokers as the reference group.

OUTCOMES

The primary outcome was the adjusted OR, RR or HR of NPC patients comparing smoking with never-smoking; the second was the crude OR, RR or HR.

RESULTS

We identified 17 case-control studies and 4 cohort studies including 5960 NPC cases and 429 464 subjects. Compared with never smokers, current smokers and ever smokers had a 59% and a 56% greater risk of NPC, respectively. A dose-response relationship was identified in that the risk estimate rose by 15% (p<0.001) with every additional 10 pack-years of smoking, and risk increased with intensity of cigarette smoking (>30 cigarettes per day). Significantly increased risk was only found among male smokers (OR, 1.36; 95% CI 1.15 to 1.60), not among female smokers (OR, 1.58; 95% CI 0.99 to 2.53). Significantly increased risk also existed in the differentiated (OR, 2.34; 95% CI 1.77 to 3.09) and the undifferentiated type of NPC (OR, 1.15; 95% CI 0.90 to 1.46). Moreover, people who started smoking at younger age (<18 years) had a greater risk than those starting later for developing NPC (OR, 1.78; 95% CI 1.41 to 2.25).

CONCLUSIONS

Cigarette smoking was associated with increased risk of NPC, especially for young smokers. However, we did not find statistical significant risks of NPC in women and in undifferentiated type, which might warrant further researches.