Epidemiology Of Nasopharyngeal Carcinoma Research Articles

PUSHING THE ENVELOPE WITH POLYGENIC RISK SCORES IN PSYCHIATRIC GENETICS: WHETHER, WHEN, AND HOW TO IMPLEMENT

Nasopharyngeal carcinoma (NPC) is considered a rare malignant head and neck tumour. However, the importance of genetics and environmental factors in the epidemiology of NPC is still unclear. Twins represent an excellent study population for genetic epidemiology; this is especially true of monozygotic-type twins because they are genetically identical. The difference in cancer occurrence between monozygotic twins is typically interpreted as a result of possible environmental factors.We present the first case report of monozygotic twins with NPC. The twins' significant features are homogenous presentation, tumour location (both left-sided) and identical histology; therefore, the prognoses may be similar. Environmental factors could not be addressed in these twins because they shared the same background, and at the same time, they had no potential known contributing factors.Having one of the twins affected is a strong and easily recognisable risk factor for developing NPC in the other. This strong association suggests the need for regular screening of the second twin for early diagnosis of NPC.

The Evolving Epidemiology of Nasopharyngeal Carcinoma.

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. This review summarizes the current epidemiologic literature on NPC, highlighting recent results from our population-based case-control study in southern China. 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. 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. New epidemiologic findings have reshaped the causal model for NPC.

Epidemiology of nasopharyngeal carcinoma in the United States: improved survival of Chinese patients within the keratinizing squamous cell carcinoma histology

This study examined potential survival differences among nasopharyngeal carcinoma (NPC) patients from various ethnicities in the United States. A total of 2436 newly diagnosed NPC patients from 1992 to 2002 were analyzed from the population-based Surveillance, Epidemiology, and End Results (SEER) program. Five-year survival rate estimates and Kaplan-Meier survival curves were calculated. Cox proportional hazard ratios (HRs) were used to identify independent prognostic factors for survival. By multivariate analyses, early age of diagnosis, localized stage at presentation (versus distant, HR=0.35; P<0.0001), radiation therapy (versus none; HR=0.48; P<0.0001), undifferentiated non-keratinizing carcinoma (versus keratinizing squamous cell carcinoma; HR=0.67; P<0.0001), and Chinese ethnicity (versus Caucasian; HR=0.78; P=0.0010) were associated with improved survival. Within keratinizing squamous cell carcinoma histology, the survival advantage of Chinese patients remained even after adjustment for other prognostic factors. The significant survival advantage of Chinese NPC patients within the keratinizing squamous cell carcinoma histology contributed largely to Chinese ethnicity being an independent and favorable prognostic factor for survival in NPC.

Epidemiology of nasopharyngeal carcinoma (NPC) in California: Survival advantage of Chinese WHO Type 1 NPC patients resulted in Asian ethnicity as an independent and favorable prognostic factor of survival for NPC patients as a whole and for patients with the WHO histologic type 1

5514 Background: We have previously shown that Chinese race is an independent and favorable prognostic factor in NPC survival. We expanded our study to investigate whether Asian ethnicity has the same favorable survival characteristics and if there is a survival difference between Chinese and non-Chinese Asians. Methods: 1,657 newly diagnosed NPC patients from 1992 to 2002 were analysed from the population-based California Cancer Registry. Five year survival rate estimates and Kaplan-Meier curves were calculated. Cox proportional ratios were used to identify independent prognostic factor for survival. Results: The 5-year survival rate of Asian NPC patients was improved compared to non-Asian patients (62% vs 47%; P &lt; .0001). By multivariate analyses, early age of diagnosis, localized stage at presentation (vs distant, HR = 0.41; P &lt; .0001), WHO Type 3 histology (vs Type 1; HR = 0.64; P &lt; .0001), socio-economic status (highest vs lowest quartile; HR = 0.71; P = .0012), use of radiation (vs none; HR = 0.55; P &lt; .0001), and Asian ethnicity (vs Caucasian; HR = 0.82; P = .016) were associated with improved survival. Chinese composed the majority of the Asian ethnicity (49.1%) followed by Filipino (21.2%) and Vietnamese (14.9%). The 5-year survival rate of Chinese was better than non-Chinese Asians (67% vs 56%; P = .0005). When Asian ethnicity was analyzed separately as Chinese and non-Chinese, Chinese retained an overall favorable prognosis (HR = 0.72; P = .0016) whereas non-Chinese Asians did not (HR = 0.91; P = .34). Within each NPC WHO histologic type, early age of diagnosis, localized stage at presentation, and use of radiation were favorable prognostic factors. Chinese (HR = 0.62; P = .0006) but not non-Chinese Asian ethnicity (HR = 0.78; P = .053) was an additional favorable prognostic factor within WHO histologic Type 1. Conclusions: The significant survival advantage of Chinese WHO Type 1 NPC patients resulted in Asian ethnicity being an independent and favorable prognostic factor for survival in NPC. This observation may reflect underlying genetic difference among different racial groups with NPC WHO Type 1. No significant financial relationships to disclose.

Aspects of the epidemiology of nasopharyngeal carcinoma and Epstein-Barr virus infection in Greenland

Objectives. The Inuit traditionally exhibit a distinctive cancer pattern characterised by high frequencies of nasopharyngeal (NPC) and salivary gland carcinomas, and low frequencies of tumours common in Western populations. Both NPC and salivary gland carcinomas are closely associated with Epstein-Barr virus (EBV), a nearly ubiquitous infection in all populations, and infection among Inuit is characterised by a particular pattern with early primary infection and high antibody titres. NPC is believed to be the result of environmental factors, especially EBV, acting on genetically susceptible individuals. However, knowledge is sparse on the extent and importance of the individual susceptibility and the interaction with EBV. During the second half of the twentieth century considerable changes in living conditions and lifestyle have occurred in the Inuit population of Greenland, and the effects on the patterns of malignant disease and EBV acquisition are unknown.The present thesis explores different aspects of the EBV-associated carcinomas among Inuit, with emphasis on the individual susceptibility of NPC and the epidemiology of EBV infection.