Case-control study evaluating the homogeneity and heterogeneity of risk factors between sinonasal and nasopharyngeal cancers

Viral and Clinical Oncology of Head and Neck Cancers

Purpose of Review

This study assesses the current state of knowledge of head and neck squamous cell carcinomas (HNSCC), which are malignancies arising from the orifices and adjacent mucosae of the aerodigestive tracts. These contiguous anatomical areas are unique in that 2 important human oncoviruses, Epstein-Barr virus (EBV) and human papillomavirus (HPV), are causally associated with nasopharyngeal and oropharyngeal cancers, respectively. Mortality rates have remained high over the last 4 decades, and insufficient attention paid to the unique viral and clinical oncology of the different subgroups of HNSCC.

Recent Findings

We have compared and contrasted the 2 double-stranded DNA viruses and the relevant molecular oncogenesis of their respective cancers against other head and neck cancers. Tobacco and alcohol ingestion are also reviewed, as regard the genetic progression/mutation accumulation model of carcinogenesis. The importance of stringent stratification when searching for cancer mutations and biomarkers is discussed. Evidence is presented for a dysplastic/pre-invasive cancerous phase for HPV+ oropharyngeal cancers, and analogous with other HPV+ cancers. This raises the possibility of strategies for cancer screening as early diagnosis will undoubtedly save lives.

Summary

Staging and prognostication have changed to take into account the distinct biological and prognostic pathways for viral+ and viral− cancers. Diagnosis of pre-cancers and early stage cancers will reduce mortality rates. Multi-modal treatment options for HNSCC are reviewed, especially recent developments with immunotherapies and precision medicine strategies. Knowledge integration of the viral and molecular oncogenic pathways with sound planning, hypothesis generation, and clinical trials will continue to provide therapeutic options in the future.

Nonmedical Cannabis Use: Patterns and Correlates of Use, Exposure, and Harm, and Cancer Risk

Cannabis has certain health benefits, but some people may experience harms from use. Co-use of tobacco and cannabis is common. Smoke from cannabis contains many of the same carcinogens and toxicants as the smoke from tobacco, raising concerns that cannabis smoking may be a risk factor for cancer. With growing access to and acceptance of medical and nonmedical cannabis, there is an urgent need to understand the risks and benefits of the current modes of cannabis use and how cannabis may be associated with cancer risk. This monograph summarizes a session from a National Cancer Institute Symposium on nonmedical cannabis use and cancer risk. We had 3 objectives: describe the relation between nonmedical cannabis use and cancer risk, delineate patterns and correlates of cannabis co-use with tobacco, and document potentially harmful inhalational exposure resulting from smoked and vaped cannabis. Methodological limitations in the literature and future research recommendations are provided.

Scoping Review and Meta-Analysis Suggests that Cannabis Use May Reduce Cancer Risk in the United States

Introduction: Cannabis smoke contains carcinogens similar to tobacco, in addition to compounds with antitumor activity. Cannabis use reduces the risk of obesity and cannabinoids inhibit chronic inflammation, known causes of cancer. The net effect of Cannabis use on cancer risk is not known. Objective: To examine the association between Cannabis use and cancer risk in the United States. Methods: Identify and analyze published data on cancer risk in Cannabis users. Results: A total of 55 data points, consisting of risk ratios of cancer in Cannabis users and nonusers, were identified from 34 studies. Of these, 5 did not contain data essential for inclusion in the meta-analysis. The remaining data showed a nonsignificant trend to an association with reduced risk (relative risk [RR]=0.90, p>0.06, N=50) although heterogeneity is high (I²=72.4%). Removal of data with high risk of selection bias (defined as those from North Africa and those that failed to adjust for tobacco) and data with high risk of performance bias (defined as those with fewer than 20 cases or controls among Cannabis users) resulted in an RR <1.0 (RR=0.86, p<0.017, N=24) and large effect size (Hedges g=0.66), but did not decrease heterogeneity (I²=74.9). Of all cancer sites, only testicular cancer showed an RR value >1, although this was not significant and had a negligible effect size (RR=1.12, p=0.3, Hedges g=0.02). Following removal of testicular cancers the remaining data showed a decrease in risk (RR=0.87, p<0.025, N=41). Cancers of the head and neck showed a negative association with cancer risk (RR=0.83, p<0.05), with a large effect size (Hedges g=0.55), but high heterogeneity (I²=79.2%). RR did not reach statistical significance in the remaining cancer site categories (lung, testicular, obesity-associated, other). The data are consistent with a negative association between Cannabis use and nontesticular cancer, but there is low confidence in this result due to high heterogeneity and a paucity of data for many cancer types.

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.

The pesticides use and the risk for head and neck cancer: A review of case-control studies

BACKGROUND

Tobacco, alcohol consumption, and HPV infection are the most common risk factors for head and neck cancer (HNC). Despite of this, recent evidences are growing on the association between long-term exposure to pesticides and the risk of chronic diseases, including different types of cancer. The present review evaluated in current literature evidence of an association between exposure to pesticides and the occurrence of HNCs.

MATERIAL AND METHODS

A literature search of the case-control studies was conducted in the PubMed, Web of science and Cochrane databases. Methodological quality of each study was rated with the Scottish Intercollegiate Guidelines Network (SIGN 50) checklist.

RESULTS

One thousand and thirty-five studies were identified and twelve met all criteria and, therefore, considered for quality assessment and data extraction. According to SIGN 50 criteria, six studies received an overall high-quality. All the studies considered of high quality found a positive association between exposure to pesticides and different HNC sites, including larynx, pharynx and nasal cavity. In addition, the increased risk was associated with the frequency of exposure.

CONCLUSIONS

Finally, improving pesticide users' awareness of their risks and proper handling, as well as adopting protective measures such as the use of personal protective equipment, appear to be effective in reducing human health damage.

Sinonasal cancer in the Italian national surveillance system: Epidemiology, occupation, and public health implications

BACKGROUND

Sinonasal cancer (SNC) is a rare tumor with predominant occupational etiology associated with exposures to specific carcinogens. The aim of this study is to describe SNC cases recorded in Italy in the period 2000-2016.

METHODS

Clinical information, occupational history, and lifestyle habits of SNC cases collected in the Italian Sinonasal Cancer Register were examined. Age-standardized rates were estimated.

RESULTS

Overall, 1529 cases were recorded. The age-standardized incidence rates per 100 000 person-years were 0.65 in men and 0.26 in women. Occupational exposures were predominant among the attributed exposure settings, primarily to wood and leather dusts. Other putative causal agents included chrome, solvents, tannins, formaldehyde, textile dusts, and pesticides. Many cases had unknown exposure.

CONCLUSIONS

Epidemiological surveillance of SNC cases and their occupational history is fundamental for monitoring the occurrence of the disease in exposed workers in industrial sectors generally not considered at risk of SNC as well as in non-occupational settings.

Primary sinonasal lymphoma in immunocompetent patients: A 10 years retrospective clinicopathological study

Introduction:

Sinonasal tumors occur in the nasal cavity or paranasal sinuses (PNS). These tumors are rare and lymphomas are even rarer. Lymphoma of the nose and PNS may mimic benign processes and may manifest either in an isolated fashion or in conjunction with systemic diseases. B-cell lymphomas, a more favorable diagnosis, account for the majority of cases, whereas T-cell and extranodal natural killer lymphoma are associated with rapid disease progression and death.

Materials and Methods:

All patients with sinonasal lymphomas who were nonreactive for HIV and were operated and treated in our hospital from 2006 to 2016 were included in the study. Histopathological diagnosis and immunohistochemistry using a panel of antibodies (CK, CD99, CD 15, CD30, CD45, Bcl 2, anaplastic lymphoma kinase-1, CD 16, CD 57 and ki-67) were reviewed and recorded.

Results:

Out of 153 malignant sinonasal tumors, 18 were diagnosed with lymphoma. Non-Hodgkins lymphoma constituted 88.8% of cases with the most common subtype being diffuse large B-cell lymphoma (n = 12, 66.6%). Maxillary sinus was the most frequently involved site (62%). The average age of presentation was 52 years with a slight male predominance. Computed tomography and magnetic resonance imaging scans were done in virtually all cases to assess the extent of the tumor as well as bony destruction. Average 5-year survival was 50%. Local recurrence was the most frequent cause of treatment failure.

Conclusion:

Malignant lymphomas constituted 11.7% of all malignancies of PNS. The association of diffuse large B-cell tumors with obstructive nasal mass and T-cell tumors with septal perforation, orbital extension and ophthalmological symptoms were more commonly seen.

Significance of human papillomavirus positivity in sinonasal squamous cell carcinoma

BACKGROUND

The role of human papillomavirus (HPV) in sinonasal squamous cell carcinoma (SNSCC) is not well understood.

METHODS

The National Cancer Database was queried for cases of SNSCC with known HPV status. Demographics, socioeconomic variables, TNM stage, histology, grade, treatment modalities, and overall survival (OS) through 5 years were compared between HPV-positive and HPV-negative tumors. Cox proportional hazard regression analyses were performed.

RESULTS

Seven hundred seventy (770) cases were identified; 526 were HPV-negative (68.3%) and 244 (31.7%) were HPV-positive. Patients with HPV-positive tumors were younger (58.0 vs 63.7 years, p < 0.0001). Nasal cavity (49.4%) tumors were more likely to be HPV-positive (p < 0.05) than maxillary (18.8%), ethmoid (18.8%), and frontal (18.2%) sinus tumors. Large cell nonkeratinizing (42.4%), papillary (42.1%), and basaloid (56.5%) tumors were more likely than keratinizing (25.2%) tumors to be HPV-positive (p < 0.05). Well-differentiated (grade I) tumors (9.0%) were less likely than higher grade tumors to be HPV-positive (p < 0.05). Gender, race, facility type, insurance type, median income, education level, Charlson-Deyo comorbidity score, overall stage, T stage, N stage, M stage, tumor size, treatment modality, surgical approach, and surgical margins did not vary by HPV status (p ≥ 0.05). HPV-positive tumors had higher OS than HPV-negative tumors (p < 0.0001). At 5 years, OS was 68.1% and 51.5% for HPV-positive and HPV-negative tumors, respectively. On multivariate analyses, HPV positivity remained a favorable prognostic factor (hazard ratio, 0.49; 95% confidence interval, 0.34-0.70).

CONCLUSION

HPV positivity is more common in nasal cavity SCC and nonkeratinizing SNSCC. It is also a favorable prognostic factor in SNSCC. Future studies on SNSCC should take HPV positivity into consideration.

Aberrant Expression Profile of Long Noncoding RNA in Human Sinonasal Squamous Cell Carcinoma by Microarray Analysis

Objectives. This study aimed to identify aberrantly expressed long noncoding RNAs (lncRNAs) profile of sinonasal squamous cell carcinoma (SSCC) and explore their potential functions. Methods. We investigated lncRNA and mRNA expression in SSCC and paired adjacent noncancerous tissues obtained from 6 patients with microarrays. Gene ontology (GO) analysis and pathway analysis were utilized to investigate the gene function. Gene signal-network and lncRNA-mRNA network were depicted. Quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to validate 5 lncRNAs in a second set of paired SSCC and adjacent noncancerous tissues obtained from 22 additional patients. Results. We identified significantly differentially expressed lncRNAs (n = 3146) and mRNAs (n = 2208) in SSCC relative to noncancerous tissues. The GO annotation indicated that there are some core gene products that may be attributed to the progress of SSCC. The pathway analysis identified many pathways associated with cancer. The results of lncRNA-mRNA network and gene signal-network implied some core lncRNAs/mRNAs might play important roles in SSCC pathogenesis. The results of qRT-PCR showed that all of the 5 lncRNAs were differentially expressed and consistent with the microarray results. Conclusion. Our study is the first screening and analysis of lncRNAs expression profile in SSCC and may offer new insights into pathogenesis of this disease.

Surgical Techniques for Sinonasal Malignancies

Sinonasal malignancies are a rare subset of malignancies of the upper aerodigestive tract which had been traditionally approached via open techniques. This article primarily addresses a paradigm shift in endoscopic endonasal oncological resection utilizing principles of tumor disassembly and negative margins. The surgical steps to these endoscopic techniques are detailed, emphasizing principles of sound oncological resection.

Occupational exposure and sinonasal cancer: a systematic review and meta-analysis

Background

Sinonasal cancer (SNC) has been related to occupational exposures, but the relative risk associated to specific jobs and/or carcinogen exposures other than wood and leather dust is generally based on small or inadequate sample sizes and the range of observed estimates is large. This paper is aimed at investigating such relationship through a systematic review of the literature followed by a meta-analysis of studies meeting specific inclusion criteria.

Methods

Systematic search was made with PubMed, Google Scholar and Scopus engines using related keywords. Occupational exposures include wood and leather dust, formaldehyde, nickel and chromium compounds, textile industry, farming and construction. Meta-analysis of published studies after 1985 with a case-control or cohort design was performed, firstly using the fixed-effect model. Heterogeneity was assessed with the Q statistical test and quantified by the I² index. When the heterogeneity hypothesis appeared relevant, the random-effect model was chosen. Sources of heterogeneity were explored using subgroup analyses.

Results

Out of 63 reviewed articles, 28 (11 cohort, 17 case-control) were used in the meta-analysis. Heterogeneity among studies was observed and random-effects models were used. Exposure to wood dust results associated with SNC (RR_pooled = 5.91, 95% CI: 4.31-8.11 for the case-control studies and 1.61, 95% CI: 1.10-2.37 for the cohort studies), as well as to leather dust (11.89, 95% CI: 7.69-18.36). The strongest associations are with adenocarcinomas (29.43, 95% CI: 16.46-52.61 and 35.26, 95% CI: 20.62-60.28 respectively). An increased risk of SNC for exposures to formaldehyde (1.68, 95% CI: 1.37-2.06 for the case control and 1.09, 95% CI: 0.66-1.79 for the cohort studies), textile industry (2.03, 95% CI: 1.47-2.8), construction (1.62, 95% CI: 1.11-2.36) and nickel and chromium compounds (18.0, 95% CI: 14.55-22.27) was found. Subset analyses identified several sources of heterogeneity and an exposure-response relationship was suggested for wood dust (p = 0.001).

Conclusions

By confirming the strength of association between occupational exposure to causal carcinogens and SNC risk, our results may provide indications to the occupational etiology of SNC (not only wood and leather dusts). Future studies could be focused on specific occupational groups to confirm causative agents and to define appropriate preventive measures.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1042-2) contains supplementary material, which is available to authorized users.

Chronic Rhinosinusitis and the Risk of Nasopharyngeal Cancer in a Taiwanese Health Study

Background

Although epidemiological and laboratory studies report that chronic inflammatory conditions contribute to the pathogenesis of cancer, it remains controversial whether chronic rhinosinusitis (CRS) results in nasopharyngeal cancer (NPC).

Methods

Retrospective cohort study was performed from the National Health Insurance (NHI) Taiwan database. This study prospectively examined whether CRS or nasal polyposis is associated with NPC risk in the NHI, a population-based cohort of 231,490 Taiwan Chinese individuals with a mean age of 32 years, recruited between 2000 and 2006. We collected information from the Longitudinal Health Insurance Database. Each subject completed an interview including questions about medical conditions, and the NPC occurrence and survival statuses were determined by linkage to population-based NHI registries in Taiwan. In addition, each NPC and CRS subject had completed an interview on medical condition to confirm their diagnosis.

Results

After adjustment for age, sex, hypertension, diabetes mellitus, allergic rhinitis, otitis media, coronary artery disease, pharyngitis, and tonsillitis, individuals with rhinosinusitis were found to have a 3.55-fold increased risk of developing NPC compared with individuals without rhinosinusitis (hazard ratio = 3.55; 95% CI = 2.22–5.69). The same results were also observed when the study subjects were analyzed without comorbidities.

Conclusion

Adult patients with rhinosinusitis should be followed up with regard to the nasopharynx for at least 3 years, particularly repeat sinusitis patients.

Cancer incidence and mortality among temporary maintenance workers in a refinery/petrochemical complex in Korea

BACKGROUND

Petrochemical plant maintenance workers are exposed to various carcinogens such as benzene and metal fumes. In Korea, maintenance operations in petrochemical plants are typically performed by temporary employees hired as contract workers.

OBJECTIVES

The purpose of this retrospective study was to evaluate cancer risk in temporary maintenance workers in a refinery/petrochemical complex in Korea.

METHODS

Subjects consisted of 14 698 male workers registered in a regional petrochemical plant maintenance workers union during 2002-2007. Cancer mortality and incidence were identified by linking with the nationwide death and cancer registries during 2002-2007 and 2002-2005, respectively. Standardized mortality ratios (SMRs) and standardized incidence ratios (SIRs) were calculated for each cancer.

RESULTS

Increased SMR 3·61 (six cases, 95% CI: 1·32-7·87) and SIR 3·18 (five cases, 95% CI: 1·03-7·42) were observed in oral and pharyngeal cancers.

CONCLUSION

Our findings may suggest a potential association between oral and pharyngeal cancers and temporary maintenance jobs in the petrochemical industry. Future studies should include a longer follow-up period and a quantitative exposure assessment.

[Cancers of the nasal cavity and paranasal sinuses: clinicopathological, etiological and therapeutic aspects]

Sinonasal cancers are rare and are often associated with occupational exposure that should be researched. Their diagnosis is often delayed. Carcinomas are the most common histological variety. The aim of the present report is to review the main scientific literature about sinonasal cancer to identify their clinicopathological features, and their main causes and treatment modalities. The treatment of these tumors is surgical, usually followed by radiotherapy.

Risk factors for nasal malignancies in German men: the South-German Nasal cancer study

BACKGROUND

There are few studies of the effects of nasal snuff and environmental factors on the risk of nasal cancer. This study aimed to investigate the impact of using nasal snuff and of other risk factors on the risk of nasal cancer in German men.

METHODS

A population-based case-control study was conducted in the German Federal States of Bavaria and Baden-Württemberg. Tumor registries and ear, nose and throat departments provided access to patients born in 1926 or later.

RESULTS

Telephone interviews were conducted with 427 cases (mean age 62.1 years) and 2.401 population-based controls (mean age 60.8 years). Ever-use of nasal snuff was associated with an odds ratio (OR) for nasal cancer of 1.45 (95% confidence interval [CI] 0.88-2.38) in the total study population, whereas OR in smokers was 2.01 (95% CI 1.00-4.02) and in never smokers was 1.10 (95% CI 0.43-2.80). The OR in ever-smokers vs. never-smokers was 1.60 (95% CI 1.24-2.07), with an OR of 1.06 (95% CI 1.05-1.07) per pack-year smoked, and the risk was significantly decreased after quitting smoking. Exposure to hardwood dust for at least 1 year resulted in an OR of 2.33 (95% CI 1.40-3.91) in the total population, which was further increased in never-smokers (OR 4.89, 95% CI 1.92-12.49) in analyses stratified by smoking status. The OR for nasal cancer after exposure to organic solvents for at least 1 year was 1.53 (1.17-2.01). Ever-use of nasal sprays/nasal lavage for at least 1 month rendered an OR of 1.59 (1.04-2.44). The OR after use of insecticides in homes was 1.48 (95% CI 1.04-2.11).

CONCLUSIONS

Smoking and exposure to hardwood dust were confirmed as risk factors for nasal carcinoma. There is evidence that exposure to organic solvents, and in-house use of insecticides could represent novel risk factors. Exposure to asbestos and use of nasal snuff were risk factors in smokers only.

Association between adult otitis media and nasopharyngeal cancer: a nationwide population-based cohort study

PURPOSE

To determine whether the diagnosis of otitis media (OM) in adults is associated with an increased risk for the subsequent development of nasopharyngeal cancer (NPC) using a nationwide population-based retrospective study.

METHODS AND MATERIALS

We selected 13,513 adult patients that had been previously diagnosed with OM between 2000 and 2005 from the Taiwan Longitudinal Health Insurance Database 2000 as the study cohort, and randomly extracted the data of 135,130 participants matched by sex, age, and baseline year for the comparison cohort. The follow-up period was terminated upon developing NPC, withdrawal from the national health insurance system, or the end of 2009. Cumulative incidences and hazard ratios (HRs) of NPC development were determined.

RESULTS

The subsequent NPC incidence rates in the OM and comparison cohorts were 6.41 and 0.58 per 10000 person-years, respectively (adjusted HR, 11.04; 95% CI, 7.68-5.87; P<0.0001). The NPC risk for males was significantly higher than that for females (adjusted HR=3.24; 95% CI, 2.16-4.85). In both female and male patients, the diagnosis of OM was associated with a significantly increased risk for NPC (adjusted HR, 11.91 vs. 10.78, respectively). Among the OM cohort, 62 participants were subsequently diagnosed with NPC, with 71% of them occurring within 1 year following the diagnosis of OM. However, even after 5-year follow-up, the OM cohort still displayed a higher risk for NPC (adjusted HR=2.50). Stratified by the frequency of OM episodes, more than one episode per year had a significantly greater risk of developing NPC, compared with the comparison cohort (HR=29.22; 95% CI, 20.19-42.27).

CONCLUSION

We found that adult OM is a warning sign for the development of NPC in Taiwan, with approximately an 11-fold higher risk for adult OM patients. We recommend that OM patients undergo follow-up examinations for at least 5 years. To extrapolate our findings, further studies are warranted in other areas in which NPC is endemic.

An epidemiological and molecular study of the relationship between smoking, risk of nasopharyngeal carcinoma, and Epstein-Barr virus activation

BACKGROUND

Elevated levels of antibodies against antigens in the Epstein-Barr virus (EBV) lytic phase are important predictive markers for nasopharyngeal carcinoma (NPC) risk. Several lifestyle factors, including smoking, have also been associated with NPC risk. We hypothesized that some specific lifestyle factors induce transformation of EBV from the latent to the lytic stage and contribute to NPC occurrence.

METHODS

We conducted a case-control study using data from male case patients (n = 1316) and control subjects (n = 1571) living in Guangdong Province, an area in China at high risk for NPC, to study potential NPC risk factors and EBV inducers. Two independent healthy male populations from a second high-risk area (n = 1657) and a low-risk area (n = 1961) were also included in the analysis of potential EBV inducers using logistic regression models. In vitro assays were performed to investigate the effect of cigarette smoke extract on EBV activation in two EBV-positive cell lines. All statistical tests were two-sided.

RESULTS

Smoking was associated with an increased risk of NPC among the Guangdong participants with 20-40 and 40 or more pack-years vs never smokers (OR = 1.52, 95% CI = 1.22 to 1.88 and OR = 1.76, 95% CI = 1.34 to 2.32, respectively; P (trend) < .001). Smoking was the only factor linked to EBV seropositivity among the expanded control group and the independent low-risk population. In vitro experiments showed that cigarette smoke extract promoted EBV replication, induced the expression of the immediate-early transcriptional activators Zta and Rta, and increased transcriptional expression levels of BFRF3 and gp350 in the lytic phase.

CONCLUSION

Smoking is not only associated with NPC risk in individuals from China but is also associated with EBV seropositivity in healthy males and is involved in EBV activation.

Endoscopic skull base surgery for sinonasal malignancy

Management of malignant neoplasms of the sinonasal tract and skull base is hampered by the relative low incidence and pathologic diversity of patient presentations. Many studies have reported successful outcomes in the endoscopic management of malignancy since 1996, and these are summarized in this article. Nonsurgical adjuvant therapies are important for locoregional control because surgery occurs in a restricted anatomic space with close margins to critical structures, and distant disease is an ongoing concern in these disorders. There remains a need for collaborative consistent multicenter reporting, and international registries have been established to assist in such efforts.

Analysis of nicotine-induced DNA damage in cells of the human respiratory tract

Epithelium of the upper and lower airways is a common origin of tobacco-related cancer. The main tobacco alkaloid nicotine may be associated with tumor progression. The potential of nicotine in inducing DNA mutations as a step towards cancer initiation is still controversially discussed. Different subtypes of nicotinic acetylcholine receptors (nAChR) are expressed in human nasal mucosa and a human bronchial cell line representing respiratory mucosa as a possible target for receptor-mediated pathways. In the present study, both cell systems were investigated with respect to DNA damage induced by nicotine and its mechanisms. Specimens of human nasal mucosa were harvested during surgery of the nasal air passage. After enzymatic digestion over night, single cells were exposed to an increasing nicotine concentration between 0.001 mM and 4.0mM. In a second step co-incubation was performed using the antioxidant N-acetylcysteine (NAC) and the nAChR antagonist mecamylamine. DNA damage was assessed using the alkali version of the comet assay. Dose finding experiments for mecamylamine to evaluate the maximal inhibitory effect were performed in the human bronchial cell line BEAS-2B with an increasing mecamylamine concentration and a constant nicotine concentration. The influence of nicotine in the apoptotic pathway was evaluated in BEAS-2B cells with the TUNEL assay combined with flow cytometry. After 1h of nicotine exposure with 0.001, 0.01, 0.1, 1.0 and 4.0mM, significant DNA damage was determined at 1.0mM. Further co-incubation experiments with mecamylamine and NAC were performed using 1.0mM of nicotine. The strongest inhibitory effect was measured at 1.0mM mecamylamine and this concentration was used for co-incubation. Both, the antioxidant NAC at a concentration of 1.0mM, based on the literature, as well as the receptor antagonist were capable of complete inhibition of the nicotine-induced DNA migration in the comet assay. A nicotine-induced increase or decrease in apoptosis as assessed by the TUNEL assay in BEAS-2B could not be detected. These results support the hypothesis that oxidative stress is responsible for nicotine-induced DNA damage. Similar results exist for other antioxidants in different cell systems. The decrease in DNA damage after co-incubation with a nAChR antagonist indicates a receptor-dependent pathway of induction for oxidative stress. Further investigations concerning pathways of receptor-mediated DNA damage via nAChR, the role of reactive oxygen species and apoptosis in this cell system will elucidate underlying mechanisms.

Results of anterior skull base surgery in pediatric and young adult patients

We sought to better define the results of anterior skull base surgery in pediatric and young adult patients. We performed a single-institution, retrospective cohort study in a tertiary-care academic cancer center. Between 1973 and 2005, 234 patients underwent anterior skull base surgery at Memorial Sloan-Kettering Cancer Center. Of these, 19 patients were <21 years of age. Surgical indications, findings, and complications were reviewed. Survival outcomes were analyzed using the Kaplan-Meier method and compared with patients >/=21 years old. Nineteen patients <21 years old underwent a total of 20 procedures for lesions of the anterior skull base. Sarcoma was the most common indication for surgery including 6 (32%) patients treated for radiation-induced malignancies. Minor complications were noted with 6 (30%) procedures. There were no major complications and no perioperative deaths. The difference in 3-year recurrence-free (68% versus 59%; p = 0.623) and overall survival (83% versus 66%; p = 0.309) compared with patients >/=21 years old did not reach statistical significance. Anterior skull base surgery is well tolerated in pediatric and young adult patients <21 years of age. Survival is comparable to older patients treated similarly and appears strongly influenced by histology.

Human papillomavirus and WHO type I nasopharyngeal carcinoma

OBJECTIVES

Nasopharyngeal carcinoma (NPC) is a rare cancer in the United States. An association between NPC and Epstein-Barr virus (EBV) is well-established for World Health Organization (WHO) types II and III (WHO-II/III) NPC but less well-established for WHO type I (WHO-I) NPC. Given the rise in oropharyngeal tumors positive for high-risk human papillomavirus (HPV) and the unique biology of WHO-I NPC, we examined the relationship between HPV and WHO-I NPC.

STUDY DESIGN

Retrospective case-comparison study.

METHODS

A search of a large multidisciplinary cancer center tumor registry identified 183 patients seen from January 1999 to December 2008 with incident NPC and no prior cancer. Available paraffin-embedded tumor specimens (N = 30) were analyzed for oncogenic HPV status by in situ hybridization (ISH) and polymerase chain reaction (PCR) for HPV-16 and HPV-18; EBV status by ISH; and p16 expression by immunohistochemistry. Demographic parameters, including race and smoking, were obtained from the medical records.

RESULTS

Among the 18 WHO-I NPC patients, 66% (N = 12) were smokers and 17% (N = 3) Asian; among the 165 WHO-II/III NPC patients, 44% (N = 73) were smokers and 24% (N = 39) Asian. Eight WHO-I NPC patients had available paraffin blocks; five of six were HPV-16-positive by PCR and four of eight were HPV-positive by ISH; only two of eight (25%) were EBV-positive. Twenty-two WHO-II/III NPC patients had available paraffin blocks; only 1 was HPV-positive by ISH, and 13 of 22 (60%) were EBV-positive.

CONCLUSIONS

These results suggest that WHO-I NPC is associated with oncogenic HPV, although larger studies are needed to verify these findings. Laryngoscope, 2010.

Hypothesizing that marijuana smokers are at a significantly lower risk of carcinogenicity relative to tobacco-non-marijuana smokers: evidenced based on statistical reevaluation of current literature

A hypothetical link between marijuana smoking and cancer has been established based on a number of misleading assumptions. However, recent studies tend to suggest, if anything, an inverse association between marijuana use and cancers. To test the hypothesis that marijuana smoking significantly lowers the risk of developing cancer in humans, we analyzed published data from a prospective cohort study on cancer incidence among nonsmokers (NS), marijuana-only smokers (MS), tobacco-only smokers (TS), and marijuana and tobacco smokers (MTS). Using the log linear model to calculate the probability of developing each cancer form as a function of the interaction between marijuana and tobacco smoking, as well as functions of marijuana and tobacco smoking main effects whereby chi square statistics were calculated for the interaction and main effect estimates, we found that in all cases tested there was a significantly lower risk for MS compared to TS. Male and female TS had a greater probability of developing lung cancer than did MS. Males and females TS had a greater probability of developing lung cancer compared with NS. Males and female MTS had a slightly higher probability of developing lung cancer than did MS. This difference was statistically significant: chi2 = 30.51, p < .00001, with a correlation coefficient of -0.75, Z = -7.84, p < .05. Male and female MTS had a lower probability of developing lung cancer than did TS. This difference was statistically significant: chi2 = 71.61, p = .00003, with a correlation coefficient of 0.61, Z = 5.06, p < .05.

Pentachlorophenol and cancer risk: focusing the lens on specific chlorophenols and contaminants

OBJECTIVE

Pentachlorophenol, a fungicide widely used as a wood preservative, was classified in 1999 by the International Agency for Research on Cancer as a possible human carcinogen. We reviewed currently available data to determine the extent to which recent studies assist in distinguishing the effect of pentachlorophenol from that of its contaminants (e.g., dioxins and other chlorophenols).

DATA SOURCES AND EXTRACTION

We performed a systematic review of published studies pertaining to cancer risk in relation to pentachlorophenol exposure, focusing on results pertaining specifically to all cancer sites and specific hematopoietic cancers, and data pertaining to risks associated with other types of chlorophenols, dioxins, or furans.

SYNTHESIS

The pentachlorophenol studies presented considerable evidence pertaining to hematopoietic cancers, with strong associations seen in multiple studies, in different locations, and using different designs. There is little evidence of an association between these cancers and chlorophenols that contain fewer than four chlorines. The extension of a large cohort study of sawmill workers, with follow-up to 1995, provided information about risks of relatively rare cancers (e.g., non-Hodgkin lymphoma, multiple myeloma), using a validated exposure assessment procedure that distinguishes between exposures to pentachlorophenol and tetrachlorophenol. In contrast with dioxin, pentachlorophenol exposure has not been associated with total cancer incidence or mortality.

CONCLUSIONS

The updated cohort study focusing on pentachlorophenol provides increased statistical power and precision, and demonstrates associations between hematopoietic cancer and pentachlorophenol exposure not observed in earlier evaluations of this cohort. Contaminant confounding is an unlikely explanation for the risks seen with pentachlorophenol exposure.

A prospective study of tobacco and alcohol use as risk factors for pharyngeal carcinomas in Singapore Chinese

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a rare disease in most populations; however, in areas of Southeast Asia and North Africa and in the Arctic, undifferentiated NPC is the most frequent pharyngeal malignancy. Although smoking and alcohol have been established firmly as synergistic risk factors for other pharyngeal carcinomas, previous studies on the association between these risk factors and NPC have not been consistent. Therefore, the authors analyzed this relation in a cohort of Singapore Chinese, which is a population with a high incidence of NPC.

METHODS

From 1993 to 1998, a population-based cohort of 61,320 Singapore Chinese ages 45 years to 74 years who were free of cancer completed a comprehensive interview on living conditions and dietary and lifestyle factors. By linkage to Singapore population-based registries, the cohort was followed through 2005, and cancer occurrence was determined. The relative risk of NPC and other oropharyngeal carcinomas in the cohort was investigated by using a Cox proportional hazards model.

RESULTS

In total, 173 NPCs and 75 other oropharyngeal carcinomas were observed during 601,879 person-years of follow-up. Smoking for >40 years was associated with a doubled risk of NPC (relative risk, 2.0; 95% confidence interval, 1.2-3.3), whereas smoking intensity, age at smoking initiation, and alcohol consumption were not associated with NPC risk. In contrast, smoking duration, smoking intensity, age at smoking initiation, and alcohol consumption all were associated with an increased risk of other oropharyngeal carcinoma (P for trend, <.0001).

CONCLUSIONS

Smoking and alcohol influenced the risk of NPC and other oropharyngeal carcinomas differently in a high-incidence NPC population. Long-term smoking was a risk factor for NPC, but alcohol consumption was not.

The enigmatic epidemiology of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) has a unique and complex etiology that is not completely understood. Although NPC is rare in most populations, it is a leading form of cancer in a few well-defined populations, including natives of southern China, Southeast Asia, the Arctic, and the Middle East/North Africa. The distinctive racial/ethnic and geographic distribution of NPC worldwide suggests that both environmental factors and genetic traits contribute to its development. This review aims to summarize the current knowledge regarding the epidemiology of NPC and to propose new avenues of research that could help illuminate the causes and ultimately the prevention of this remarkable disease. Well-established risk factors for NPC include elevated antibody titers against the Epstein-Barr virus, consumption of salt-preserved fish, a family history of NPC, and certain human leukocyte antigen class I genotypes. Consumption of other preserved foods, tobacco smoking, and a history of chronic respiratory tract conditions may be associated with elevated NPC risk, whereas consumption of fresh fruits and vegetables and other human leukocyte antigen genotypes may be associated with decreased risk. Evidence for a causal role of various inhalants, herbal medicines, and occupational exposures is inconsistent. Other than dietary modification, no concrete preventive measures for NPC exist. Given the unresolved gaps in understanding of NPC, there is a clear need for large-scale, population-based molecular epidemiologic studies to elucidate how environmental, viral, and genetic factors interact in both the development and the prevention of this disease.

Squamous cell carcinoma of the sinonasal cavity arising as a second primary in individuals with head and neck cancer

OBJECTIVES/HYPOTHESIS

Second primary tumors occur frequently in patients with head and neck carcinoma. This may be caused by generalized exposure to carcinogens resulting in "field cancerization" or to the individuals' generalized susceptibility to cancer. The paranasal sinuses are not commonly included in the sites considered at risk for this process. We therefore sought to assess the overall risk of contracting a primary cancer in this region after having a tumor elsewhere in the upper aerodigestive tract.

STUDY DESIGN

Retrospective.

METHODS

Two thousand four hundred seventy-five patients with squamous cell carcinoma of the upper aerodigestive tract were analyzed using a tumor registry at a tertiary care institution.

RESULTS

Five (0.2%) patients were identified as having a second primary in the sinonasal tract. The average interval between the index and second primary tumors was 28.4 (range 8-60) months. All five patients presented with symptoms typical of sinus inflammatory disease and had advanced sinus lesions at the time of diagnosis. These findings are typical of those with sinonasal carcinoma in that they present with nonspecific signs and symptoms and were diagnosed with locally advanced disease despite being in a surveillance program for their index cancer.

CONCLUSIONS

Although uncommon, the data reported here support inclusion of the sinonasal tract in these surveillance programs. This could result in earlier detection and greater opportunity for curative intervention.

After the Smoke Clears

Both environmental and occupational exposures are associated with the development of carcinomas of the upper aerodigestive tract, although most squamous cell carcinomas of the upper aerodigestive tract are related to smoking and drinking. This review discusses environmental and occupational risk factors, other than tobacco and alcohol, for carcinoma of the upper aerodigestive tract and the difficulties encountered when attempts are made to study these environmental and occupational exposures. However, this is not an all-inclusive review; rather, it is designed to give the reader an understanding of the topic, to allow for appropriate counseling of patients, and perhaps to advance public health initiatives.

Descriptive epidemiology and risk factors for head and neck cancer

Although more common in developing countries, over 11,000 deaths will occur in the United States from head and neck cancer in 2004. Squamous cell carcinomas account for the vast majority of cases in the United States and the majority of these are related to exposure to tobacco and alcohol. Newer data suggest a genetic contribution. This group is the focus of primary and secondary preventative efforts.

Sinonasal malignancies

Sinonasal malignancies are highly heterogeneous lesions that are challenging to diagnose, treat, and follow clinically. Outcomes remain relatively poor and are associated with late diagnosis, difficult surgical anatomy, and a lack of effective adjuvant modalities of treatment. New multimodal treatment protocols addressed to specific tumor entities are being assessed with promising results. Because of the relative rarity of these lesions, however, progress is slow. The best therapeutic outcomes are achieved in the setting of early diagnosis combined with a meticulous, comprehensive, multidisciplinary approach to the management of these complex tumors.