Oral and pharyngeal cancer and occupation: a case-control study

Gingiva squamous-cell carcinoma in a non-smoking patient with occupational exposure to solvent siphoning using mouth: case report and literature review

Background

While overall head and neck cancer incidence decreases due to reduced tobacco and alcohol consumption, the incidence of HPV negative oral cavity squamous cell carcinoma (SCC) is raising in several industrialized countries, especially in non-smoking and non-drinking patients.

Case presentation

We document a case of gingiva SCC in a 56 years old never-smoker patient reporting low alcohol consumption and unusual occupational solvent exposure. The HPV-negative lesion was surgically removed in 2018, and the patient remains in complete remission 4 years after recurrent surgery in 2019. In 2021, the patient was referred to the occupational cancer consultation. The patient worked as screen printer for 18 years. He reported mouth siphoning every 2-3 days to transfer organic solvents (mainly aromatic hydrocarbons and ketones) from containers into smaller recipients, with regular passage of solvents into his mouth.

Conclusion

According to the literature, the frequency of solvent siphoning using mouth is likely to be underestimated. While our review did not find studies reporting longterm consequences to the oral cavity of mouth siphoning, current evidence supports a positive association of upper aero digestive tract SCC with occupational exposures to organic solvents and printing processes. In absence of major extraprofessional factors, the HPV-negative gingiva SCC of this patient might be attributable to the regular occupational oral solvent exposure. While the available evidence remains limited to formally establish a causal relationship, clinicians should investigate this hazardous work practice in patients with OSCC and history of solvent exposures.

Data-Driven Quantitative Structure-Activity Relationship Modeling for Human Carcinogenicity by Chronic Oral Exposure

Traditional methodologies for assessing chemical toxicity are expensive and time-consuming. Computational modeling approaches have emerged as low-cost alternatives, especially those used to develop quantitative structure-activity relationship (QSAR) models. However, conventional QSAR models have limited training data, leading to low predictivity for new compounds. We developed a data-driven modeling approach for constructing carcinogenicity-related models and used these models to identify potential new human carcinogens. To this goal, we used a probe carcinogen dataset from the US Environmental Protection Agency's Integrated Risk Information System (IRIS) to identify relevant PubChem bioassays. Responses of 25 PubChem assays were significantly relevant to carcinogenicity. Eight assays inferred carcinogenicity predictivity and were selected for QSAR model training. Using 5 machine learning algorithms and 3 types of chemical fingerprints, 15 QSAR models were developed for each PubChem assay dataset. These models showed acceptable predictivity during 5-fold cross-validation (average CCR = 0.71). Using our QSAR models, we can correctly predict and rank 342 IRIS compounds' carcinogenic potentials (PPV = 0.72). The models predicted potential new carcinogens, which were validated by a literature search. This study portends an automated technique that can be applied to prioritize potential toxicants using validated QSAR models based on extensive training sets from public data resources.

Occupational exposure and risk of oral and oropharyngeal squamous cell carcinoma: systematic review and 25-year retrospective cohort study of patients

Social habits such as smoking and drinking alcohol are well-known causative agents for oral and oropharyngeal squamous cell carcinoma (OSCC/OPSCC). Human papillomavirus (HPV) is a known causative agent for OPSCC. However, we often encounter patients with no identifiable risk factors. There is growing evidence of the role of occupational carcinogens in the pathogenesis of oral cancer. The aim of this study therefore was to identify any occupational carcinogens linked to oral cancer. We carried out a systematic review of the literature using PubMed, EMBASE, and Medline, along with a retrospective review of patients treated in a regional unit over 25 years. Occupations were classified based on the UK Standard of Classification 2020. Data analysis was completed using the chi-squared test. A total of 17 papers met the inclusion criteria for review. In our retrospective study a total of 874 patients were identified of whom 31% were blue-collar workers, 32.8% were white-collar workers, 20.2% were unemployed/housewives, and 16% workers in other occupations. The majority of blue-collar workers were in the construction industry and had maximum exposure to hydrocarbons and exhaust fumes. The aetiology of oral and oropharyngeal SCC is multifactorial and there is no consensus on the role of occupational carcinogens. We showcase our patient cohort and discuss the occupational exposures that appear to make them susceptible to OSCC and OPSCC. Further multicentre studies are required to enable us to understand fully the pathogenesis of oral cancer and help us to inform relevant organisations, the aim being to reduce the incidence of occupation-related cancer.

Welding and the risk of head and neck cancer: the ICARE study

OBJECTIVE

To investigate the association between occupational exposure to welding and the risk of head and neck cancer in a large French population-based case-control study, the Investigation of occupational and environmental CAuses of REspiratory cancers study.

METHODS

Analyses were restricted to men (2703 controls and 1588 cases of squamous-cell carcinoma of the oral cavity, oropharynx, hypopharynx and larynx). Welding activity and potential confounders were assessed by detailed questionnaires. ORs and CIs (95% CI) were estimated by unconditional logistic regression, adjusted for age, area of residence, tobacco smoking, alcohol consumption and occupational exposure to asbestos.

RESULTS

Welding was associated with an increased risk of head and neck cancer overall (OR=1.31, 95% CI 1.03 to 1.67). The association was strongest for laryngeal cancer (OR=1.66, 95% CI 1.15 to 2.38) and the risk increased with the cumulative duration (p-trend <0.01) and the weighted duration (p-trend <0.01) of welding. A cumulative duration and a weighted duration of welding of more than 10 years were also associated with a significantly increased risk of oral cancer (OR=1.82, 95% CI 1.09 to 3.04; OR=2.10, 95% CI 0.99 to 4.45, respectively). A long duration of arc welding was associated with laryngeal cancer, whereas a long duration of spot welding was associated with oral cancer. Welding was not associated with the risk of oropharyngeal and hypopharyngeal cancer.

CONCLUSION

Our findings suggest that welding and several welding-related tasks increase the risk of laryngeal cancer and to a lesser extent oral cancer.

Occupational exposure to solvents and risk of head and neck cancer in women: a population-based case-control study in France

OBJECTIVE

Our objective was to investigate the association between head and neck cancer and occupational exposure to chlorinated, oxygenated and petroleum solvents in women.

METHODS

Investigation of occupational and environmental CAuses of REspiratory cancers (ICARE), a French population-based case-control study, included 296 squamous cell carcinomas of the head and neck (HNSCC) in women and 775 female controls. Lifelong occupational history was collected. Job-exposure matrices allowed to assess exposure to 5 chlorinated solvents (carbon tetrachloride; chloroform; methylene chloride; perchloroethylene; trichloroethylene), 5 petroleum solvents (benzene; special petroleum product; gasoline; white spirits and other light aromatic mixtures; diesel, fuels and kerosene) and 5 oxygenated solvents (alcohols; ketones and esters; ethylene glycol; diethyl ether; tetrahydrofuran). OR and 95% CIs, adjusted for smoking, alcohol drinking, age and geographical area, were estimated with logistic models.

RESULTS

Elevated ORs were observed among women ever exposed to perchloroethylene (OR=2.97, 95% CI 1.05 to 8.45) and trichloroethylene (OR=2.15, 95% CI 1.21 to 3.81). These ORs increased with exposure duration (OR=3.75, 95% CI 0.64 to 21.9 and OR=4.44, 95% CI 1.56 to 12.6 for 10 years or more, respectively). No significantly increased risk of HNSCC was found for occupational exposure to the other chlorinated, petroleum or oxygenated solvents.

CONCLUSIONS

These findings suggest that exposure to perchloroethylene or trichloroethylene may increase the risk of HNSCC in women. In our study, there is no clear evidence that the other studied solvents are risk factors for HNSCC.

Occupational risk factors for prostate cancer in an area of former coal, iron, and steel industries in Germany. Part 1: Results from a study performed in the 1980s

Prostate cancer is the most frequent occurring malignancy in men in many Western countries. Unfortunately, only a few studies on occupational risk factors have been published. Thus, the aim of this study was to investigate possible occupational risk factors in a former center of coal, iron, and steel industries the greater Dortmund area, located in the western part of Germany. In three local departments of urology, a total of 238 prostate cancer cases and 414 patients with benign prostatic hyperplasia as controls were requested to provide information for all jobs ever performed for 6 mo or longer. Jobs performed less than 10 yr prior to diagnosis were excluded from the analysis due to the latency of prostate cancer. In addition, data on smoking habits and age were obtained. Analysis of data was performed by means of logistic regression. Hard coal miners and, based on fewer cases, painters, stratified by age, showed a significantly elevated prostate cancer risk. Smoking history did not influence prostate cancer risk. The causes of the observed increased prostate cancer risk in hard coal miners cannot be explained by merely the risk factor "male sexual hormones." In former decades, underground hard coal miners were exposed to high concentrations of dust and different xenobiotics such as hydraulic oils. Surprisingly, in a study performed about a decade later in the same area, prostate cancer risk in underground hard coal miners was found to be reduced. However, exposure to colorants was associated with an increased prostate cancer risk.

Occupation and head and neck cancer in women-Results of the ICARE study

BACKGROUND

Few occupational studies have addressed head and neck cancer, and these studies have been predominantly conducted in men. Accordingly, our objective was to investigate the association between head and neck cancer and occupation in women.

METHODS

ICARE, a French population-based case-control study, included 296 squamous cell carcinomas of the head and neck in women and 775 controls. Lifelong occupational history was collected. Odds ratios (ORs) and 95% confidence intervals (CI), adjusted for smoking, alcohol drinking and education level, were estimated for occupations and industries.

RESULTS

An elevated OR was observed for working proprietors working for 10 years or more (OR = 3.83, 95% CI: 1.12-13.0) with a significant trend with duration of employment (P = 0.047). Elevated but non-significant ORs were observed for street vendors (OR = 3.76, 95% CI: 0.99-14.3, P for trend = 0.13), bakers (OR = 4.19, 95% CI: 0.63-27.9, P for trend = 0.06), and welders and flame cutters (OR = 2.18, 95% CI: 0.33-14.4, P for trend = 0.05).

CONCLUSIONS

This exploratory study suggests a role of occupational exposures in the development of HN cancer in women. Further investigations of exposures to specific agents are needed.

Occupation and head and neck cancer risk in men: results from the ICARE study, a French population-based case-control study

OBJECTIVE

To investigate the associations between occupations and head and neck (HN) cancer risk in men.

METHODS

ICARE is a French population-based case-control study on HN cancer. Analyses included 1833 cases and 2747 controls. Complete occupational history was collected. Odds ratios (ORs) were estimated for occupations and industries ever held and according to duration of employment.

RESULTS

Elevated ORs, increasing with duration of employment, were observed for several occupations, including cleaners (OR = 1.7; 95% confidence interval [CI], 1.0 to 2.8), launderers (OR = 6.8; CI, 1.3 to 34.4), firefighters (OR = 3.9; CI, 1.4 to 11.2), several agricultural occupations, welders (OR = 1.9; CI, 1.3 to 2.8), structural metal preparers and erectors (OR = 2.1; CI, 1.2 to 3.7), rubber workers (OR = 2.0; CI, 1.0 to 3.9), several construction occupations, and material-handling equipment operators (OR = 1.8; CI, 1.1 to 2.9). Analyses by industry corroborated these findings.

CONCLUSIONS

These results confirmed the role of occupational exposures in HN cancer.

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.

Risk of laryngeal and nasopharyngeal cancer associated with arsenic and cadmium in the Tunisian population

Chronic exposure to heavy metals has long been recognized as being capable of increasing head and neck cancer (HNC) incidence, such as laryngeal (LC) and nasopharyngeal (NPC), among exposed human populations. The aim of the present study was to evaluate the concentrations of arsenic (As) and cadmium (Cd) in the blood of 145 patients (LC and NPC) and 351 controls in order to establish a potential relationship between these factors and the occurrence of LC and NPC. Mean blood levels of As and Cd in patients (5.67 and 3.51 μg/L, respectively) were significantly higher than those of controls (1.57 and 0.74 μg/L, respectively). The blood levels of As and Cd were mostly significantly higher than those of controls (p<0.05) after controlling the other risk factors of HNC including tobacco smoking and chewing, and alcohol drinking. Cd levels in blood increase significantly with the number of occupational exposure years for patients (p<0.05). However, seafood was not found to be contributing as an exposure source. Among these risk factors, smoking (>30 pack years) and occupational exposure (>20 years) presented the most significant association with HNC (OR=10.22 and 10.38, respectively, p<0.001). Cd level in blood sample of cases that are occupationally exposed/tobacco users (smokers and chewers) were higher than that of non-occupationally exposed/nontobacco users (p<0.001). The logistic regression model illustrated that HNC (LC+NPC) was significantly associated with blood levels of As (OR=2.41, p<0.001) and Cd (OR=4.95, p<0.001).

Blood nickel and chromium levels in association with smoking and occupational exposure among head and neck cancer patients in Tunisia

Chronic exposure to chromium (Cr) and nickel (Ni) has long been recognized as being capable to increase head and neck cancer (HNC) incidence among exposed human populations. This study represents the first biomonitoring of Cr and Ni exposure in Tunisia and focuses on a possible association with HNC risk. The aim of the present study was to evaluate the concentrations of Cr and Ni in the blood of HNC patients and controls. Metals blood levels of 169 HNC patients and 351 controls were determined using a Perkin-Elmer Analyst 800 Atomic Absorption Spectrometer. Mean blood levels of Cr and Ni in HNC cases (52.15 and 111.60 μg/L, respectively) were significantly higher than those of controls (37.04 and 30.50 μg/L, respectively). Cases' blood levels of Cr and Ni were significantly higher than those of controls after controlling for the other risk factors of HNC, including smoking, shisha consumption, occupational exposure, and nearby environment (P<0.05). Among these risk factors, smoking and occupational exposure presented the most significant association with HNC (odds ratio (OR)=6.54 and 7.66, respectively, P<0.001). Cr and Ni levels in blood sample of cases and controls that are smoker/occupationally exposed were higher than that of non-smoker/non-occupationally exposed (P<0.05). Smokers who are occupationally exposed present the most significant association with HNC (OR=25.08, P<0.0001). High levels of blood Cr (OR=2.09) and high levels of blood Ni (OR=8.87) were strongly associated with HNC after other potential confounders were controlled (P=0.004 and P<0.0001, respectively). This study suggested a potential role of Cr and Ni in the mechanism of HNC development.

Occupational asbestos exposure is associated with pharyngeal squamous cell carcinoma in men from the greater Boston area

OBJECTIVES

Asbestos is the name given to a group of naturally occurring silicate mineral fibres that were widely used in industry during the 20th century due to their desirable physical properties. Although use in the USA has fallen over the last three decades, significant exposure in the developing world continues and the burden of disease is considerable. Asbestos is a known risk factor for several malignant diseases, including lung cancer and mesothelioma, and has more recently been implicated in pharyngeal and laryngeal cancer. However, studies of asbestos and cancers of the larynx or pharynx with adequate sample size that control for major head and neck squamous cell carcinoma (HNSCC) risk factors remain relatively sparse.

METHODS

We report findings from a case-control study of 674 incident male HNSCC cases from the greater Boston region and 857 population-based male controls, matched on age (±3 years), sex, and town or neighbourhood of residence. Multivariable logistic regression was used to assess the association between occupational asbestos exposure and HNSCC by primary tumour site.

RESULTS

190 cases (28.2%) and 203 controls (23.7%) reported occupational exposure to asbestos. Occupational asbestos exposure was associated with elevated risk of pharyngeal carcinoma in men (OR 1.41, 95% CI 1.01 to 1.97), adjusted for age, race, smoking, alcohol consumption, education, income and HPV16 serology, with borderline increasing risk for each decade in the exposed occupation (OR 1.10, 95% CI 0.99 to 1.23).

CONCLUSIONS

These observations are consistent with mounting evidence that asbestos is a risk factor for pharyngeal cancer.

A review of risk factors for oral cavity cancer: the importance of a standardized case definition

The aim of this work is to review the literature on risk factors of oral cavity cancer with a special attention to the definition of the cases, in order to highlight special features of these cancers and of their subsites. PubMed database was systematically searched to access relevant articles published between 1980 and 2010. Reference lists of selected papers were examined to identify further articles. One hundred and two studies met the inclusion criteria. Their results were difficult to compare because of the lack of uniformity in defining oral cavity. In addition, few studies examined risk factors other than alcohol and tobacco, and studies differentiating between subsites were rare. Despite these limitations, some characteristics of oral cavity cancers may be emphasized: smoked tobacco seems to be a stronger risk factor for oral cavity cancer than alcohol, and the floor of the mouth seems to be more sensitive to the harmful effects of alcohol and smoked tobacco. Studies limited strictly to oral cavity cancers and distinguishing between subsites are needed to better understand the aetiology of these cancers, and better define risk groups to target prevention efforts and screening.

A review of the epidemiology of oral and pharyngeal carcinoma: update

Oral and pharyngeal cancers are the sixth most common cancers internationally. In the United States, there are about 30,000 new cases of oral and pharyngeal cancers diagnosed each year. Furthermore, survival rates for oral and pharyngeal cancers have not significantly improved over the last three decades. This review examines the scientific literature surrounding the epidemiology of oral and pharyngeal cancers, including but not limited to risk factors, disparities, preventative factors, and the epidemiology in countries outside the United States. The literature review revealed that much of the research in this field has been focused on alcohol, tobacco, and their combined effects on oral and pharyngeal cancers. The literature on oral and pharyngeal cancer disparities among racial groups also appears to be growing. However, less literature is available on the influence of dietary factors on these cancers. Finally, effective interventions for the reduction of oral and pharyngeal cancers are discussed.

Investigation of occupational and environmental causes of respiratory cancers (ICARE): a multicenter, population-based case-control study in France

BACKGROUND

Occupational causes of respiratory cancers need to be further investigated: the role of occupational exposures in the aetiology of head and neck cancers remains largely unknown, and there are still substantial uncertainties for a number of suspected lung carcinogens. The main objective of the study is to examine occupational risk factors for lung and head and neck cancers.

METHODS/DESIGN

ICARE is a multi-center, population-based case-control study, which included a group of 2926 lung cancer cases, a group of 2415 head and neck cancer cases, and a common control group of 3555 subjects. Incident cases were identified in collaboration with cancer registries, in 10 geographical areas. The control group was a random sample of the population of these areas, with a distribution by sex and age comparable to that of the cases, and a distribution by socioeconomic status comparable to that of the population. Subjects were interviewed face to face, using a standardized questionnaire collecting particularly information on tobacco and alcohol consumption, residential history and a detailed description of occupational history. Biological samples were also collected from study subjects. The main occupational exposures of interest are asbestos, man-made mineral fibers, formaldehyde, polycyclic aromatic hydrocarbons, chromium and nickel compounds, arsenic, wood dust, textile dust, solvents, strong acids, cutting fluids, silica, diesel fumes, welding fumes. The complete list of exposures of interest includes more than 60 substances. Occupational exposure assessment will use several complementary methods: case-by-case evaluation of exposure by experts; development and use of algorithms to assess exposure from the questionnaires; application of job-exposure matrices.

DISCUSSION

The large number of subjects should allow to uncover exposures associated with moderate increase in risks, and to evaluate risks associated with infrequent or widely dispersed exposures. It will be possible to study joint effects of exposure to different occupational risk factors, to examine the interactions between occupational exposures, tobacco smoking, alcohol drinking, and genetic risk factors, and to estimate the proportion of respiratory cancers attributable to occupational exposures in France. In addition, information on many non-occupational risk factors is available, and the study will provide an excellent framework for numerous studies in various fields.

Occupational exposures to asbestos, polycyclic aromatic hydrocarbons and solvents, and cancers of the oral cavity and pharynx: a quantitative literature review

PURPOSE

The role of occupational risk factors in oral and pharyngeal cancer is not well known and is possibly underestimated. This quantitative review summarizes epidemiological findings on exposure to asbestos, polycyclic aromatic hydrocarbons and solvents, and cancers of the oral cavity and pharynx.

METHODS

A systematic literature search was performed. We analyzed 63 publications: 8 from case-control studies and 55 from cohort studies. For agents with at least five available studies with homogenous exposure, a series of meta-analyses was conducted to provide quantitative pooled estimates of risks, using random effect models.

RESULTS

Exposure to asbestos (meta-RR 1.25; 95% CI 1.10-1.42) and to polycyclic aromatic hydrocarbons (meta-RR 1.14; 95% CI 1.02-1.28) was found to be associated with oral and pharyngeal cancer risk. On the other hand, no association was found with exposure to solvents in general (meta-RR 0.98; 95% CI 0.77-1.23) but the strong heterogeneity between studies suggested differences in exposures. The small number of studies with homogeneous exposure did not allow meta-analyses for specific solvents.

CONCLUSIONS

Future investigations should overcome common weaknesses of past studies, in terms of sample size, characterization of exposure, and classification of cancer sites.

Work in the metal industry and nasopharyngeal cancer mortality among formaldehyde-exposed workers

OBJECTIVE

To investigate further the possibility that the large nasopharyngeal cancer (NPC) mortality excess among a cohort of formaldehyde-exposed workers may be related to occupational factors external to the study plant.

METHODS

Subjects were 7345 workers employed at a plastics-producing plant (1941-1984) in Wallingford, Connecticut evaluated independently as part of a National Cancer Institute cohort study. Vital status for 98% of the cohort and cause of death for 95% of 2872 deaths were determined through 2003. Reconstructed worker exposures to formaldehyde were used to compute unlagged and lagged exposure measures. We computed standardized mortality ratios (SMRs) based on US and local county rates. In a nested case-control study we evaluated mortality risks from NPC and from all other pharyngeal cancers combined (AOPC) in relation to formaldehyde exposure while accounting for potential confounding or effect modification by smoking or external (non-Wallingford) employment. Job applications, Connecticut commercial city directories and a previous survey were used to assign subjects to three external job groups.

RESULTS

We observed no new deaths from NPC and one additional AOPC death (pharynx unspecified) yielding, respectively, SMRs of 4.43 (7 deaths, 95% CI=1.78-9.13) and 1.71 (16 deaths, 95% CI=1.01-2.72). Five of seven NPC cases worked in silver smithing (including brass plating and other jobs related to silver or brass) or other metal work (including steel working and welding), and this type of work was relatively rare in the remaining study population (OR=14.41, 95% CI=1.08-82.1). For AOPC, we found a moderate increase in risk for other metal work (OR=1.40, 95% CI=.31-5.1). Interaction models suggested that NPC and AOPC risks were not elevated in subjects exposed only to formaldehyde.

CONCLUSIONS

The results of our nested case-control study suggest that the large nasopharyngeal cancer mortality excess in the Wallingford cohort may not be due to formaldehyde exposure, but rather reflects the influence of external employment in the ferrous and non-ferrous metal industries of the local area that entailed possible exposures to several suspected risk factors for upper respiratory system cancer (e.g., sulfuric acid mists, mineral acid, metal dusts and heat). Our findings may also help to explain why the associations with formaldehyde and nasopharyngeal cancer reported in the 1994 update of the 10-plant NCI formaldehyde cohort study were unique to the Wallingford plant (Plant 1 in NCI study). Further updates of the NCI formaldehyde cohort study should include co-exposure data on silver smithing and other metal work for all study plants to help explain the unique findings for nasopharyngeal cancer in Plant 1 compared with the other nine plants.

Ocupação e câncer da cavidade oral e orofaringe

Estudo caso-controle conduzido para avaliar a associação de exposições ocupacionais e câncer oral e orofaringe na Região Metropolitana de São Paulo. Inclui 325 casos e 468 controles, recrutados por freqüência de sexo e faixa etária, entrevistados entre janeiro de 1999 e março de 2002. A análise por ramos de atividade e ocupações foi restrita aos homens (266 casos, 362 controles) e os odds ratios (OR), calculados por regressão logística não-condicional, foram controlados por idade, tabagismo e consumo de álcool. Observou-se risco em trabalhadores de oficinas mecânicas (26 casos, 12 controles) OR = 2,45 (IC95%: 1,14-5,27), que aumentou nos que estavam empregados por dez ou mais anos (OR = 7,90; IC95%: 2,03-30,72). Os mecânicos de veículos (14 casos, 7 controles) apresentaram OR = 2,10 (IC95%: 0,78-5,68), e os expostos por 10 ou mais anos OR = 26,21 (IC95%: 2,34-294,06). Outros ramos de atividade e ocupações apresentaram OR > 1,5, porém não estatisticamente significantes. Em conclusão, emprego em oficinas mecânicas e a profissão de mecânico de automóveis revelaram risco para câncer oral e orofaringe, independente da idade, tabaco e álcool. Longas exposições aumentaram o risco.

Estudo de variáveis demográficas, ocupacionais e co-carcinogenéticas no carcinoma espinocelular da base de língua nas mulheres

Avaliar a relação entre carcinógenos e o carcinoma espinocelular no sexo feminino. FORMA DE ESTUDO: Retrospectivo não randomizado. OBJETIVO: Determinar a relação entre carcinógenos (álcool e fumo) e o carcinoma espinocelular no sexo feminino na base da língua. MATERIAL E MÉTODOS: Estudo retrospectivo de 31 pacientes do sexo feminino realizado no Departamento de Cirurgia de Cabeça e Pescoço e Otorrinolaringologia do Hospital Heliópolis, Hosphel, São Paulo (1977 a 2000). Foram analisados variáveis como etnia, idade, profissão, tabagismo, etilismo, queixa principal, o intervalo de tempo entre o início da queixa e a procura do médico e o estadiamento clínico. Quanto ao tratamento estatístico, foram utilizados os Testes de Kappa e o de Mc Nemar. RESULTADOS: Houve predomínio da raça branca (58,1%) sobre a negra (35,5%) e a amarela (6,4%), bem como da 6ª décadade vida; sendo profissionais do lar (83,9%) trabalhadoras na agricultura 6,4%). Indústria (3,2%), comércio e liberais (3,2%). Houve mais consumo isolado do tabagismo (48,4%), ambos (45,2%) e nenhum (6,4%). Quanto à sintomatologia, odinofagia (48,4%), nódulo no pescoço (19,3%), disfagia (12,9%); otalgia (9,7%), ferida na língua (6,4%) e rouquidão (3,2%). Quanto ao estadiamento, T3-4 (74,1%), T1-2 (25,8%), N0 (29,0%), N1(29,0%), N2-3 (42,0%). CONCLUSÕES: O carcinoma espinocelular em mulheres predominou na 6ª década, na raça branca, tendo como principais sintomas odinofagia e linfonodo cervical metastático. Houve predomínio do tabagismo sobre o etilismo, em paciente T3-4, sendo que a maioria já portador de metástase linfonodal à 1ª consulta.

Sugarcane farming, occupational solvent exposures, and the risk of oral cancer in Puerto Rico

The work history information from a population-based case-control study conducted in Puerto Rico was analyzed using a job exposure matrix to investigate the relationship between occupational exposures and cancers of the oral cavity or pharynx. After adjustment for age, alcohol, smoking, and residence in a logistic model, the risk for cancer of the oral cavity, but not the pharynx, was significantly elevated among farm workers in the sugarcane industry (OR = 4.4, 95% CI = 1.4-13.6). An exposure-response trend was seen for cumulative exposure to solvents, with an OR = 3.2 (95% CI = 0.8-12.6) in the highest exposure category. The overall contribution to the risk of cancer of the oral cavity or pharynx associated with occupational exposures in Puerto Rico appears to be small, however, the elevated risks were seen among sugarcane farmers and subjects with high cumulative exposure to solvents.

Estudo clínico-epidemiológico do carcinoma epidermóide da base da língua

INTRODUÇÃO: A evolução assintomática e a disseminação precoce justifica a análise de variáveis determinantes do prognóstico do carcinoma espinocelular de base de língua (CEC). OBJETIVO: estudo clínico-epidemiológico de pacientes portadores CEC de base de língua. FORMA DE ESTUDO: Retrospectivo. MATERIAL E MÉTODO: 290 pacientes com carcinoma epidermóide de base de língua (1977 a 2000), 259 homens (89,3%) e 31 mulheres (10,7%) - relação 8:1 -, 237 brancos (81,7%), 51 negros (17,6%) e 2 amarelos (0,7%) - relação 5:1. Houve predomínio da 6ª década (41,0%), 5ª e 7ª (22,7%), 8ª (3,4%) e 9ª (1,7%). Estas variáveis foram relacionadas com a profissão, hábitos e vícios (tabagismo e etilismo), estadiamento TNM, sintoma inicial, tempo entre o diagnóstico e o início do tratamento. Para análise estatística, utilizamos testes não paramétricos: Wilcoxon (tempo de consumo de álcool e fumo para cada paciente), Kruskal Wallis (álcool e fumo e o estadiamento TNM para cada paciente), Kappa (concordância entre o grau de consumo do álcool e fumo para cada estádio TNM e para cada grupo de pacientes segundo a ocupação), e Mc Nemar (complementar ao Kappa - determinação das frequências acima e abaixo da diagonal de concordância). Como nível de rejeição da hipótese de nulidade, fixou-se como valor significante 0,05 ou 5%. RESULTADOS: Predominaram pacientes ligados à indústria (36,6%) seguido de comerciários e liberais (34,5%), agricultores (7,9%) e aposentados (7,3%). Houve predomínio do grupo dos 30 aos 59 anos (61,1%) e do tempo de queixa de até 180 dias (62,0%). A odinofagia (37,2%) foi a queixa principal, linfonodo metastático (21,8%), disfagia (14,5%), ferida na língua (9,0%), rouquidão (6,9%) corpo estranho (4,8%), otalgia (3,4%) outras (2,0%). Quanto aos hábitos, etilismo e tabagismo (83,8%), tabagismo (10,3%), etilismo (1,4%) e nenhum (4,5%). Houve relação de 9:1 dos estádios III e IV (avançados) em relação ao I e II (iniciais), sendo que todos I, II e IV eram tabagistas e ou etilistas, unanimidade não encontrada nos casos III, IVa, IVb e IVc (23,1%, 53,8% e 23,1% respectivamente). Quanto ao parâmetro T, 241 (83,1%) eram T3 e T4 e 49(16,9%) eram T1 e T2. Quanto ao N, 61(21,6%) eram N0, 39(13,4%) N1, 125(43,0%) N2 e 65(22,4%) N3, sendo o nível II (69,0%) o mais acometido, seguido do nível III - 57 casos (13,5%), do I - 49 casos (11,6%), do IV - 25 casos (15,9%). CONCLUSÕES: O carcinoma espinocelular de base de língua é mais freqüente no homem branco da 5ª a 6ª década, tendo como fatores de risco o álcool e o fumo, sendo predominante o emprego do tabagismo nas mulheres. O tempo de queixa foi referido nos 6 meses iniciais, com predomínio dos estádios III e IV, sendo que os casos I e II eram todos etilistas e/ou tabagistas.

The epidemiology of oral and pharynx cancer in Brazil

A study was carried out on the occurrence of oral and pharynx cancer among populations living in five Brazilian geographic regions, by using incidence and mortality rates and trends. Information on survival was also analyzed. Complementary information regarding prevalence of the disease risk factors has been supplied in the attempt to establish some etiological connections with the incidence and mortality observed. Two clear patterns for the occurrence of oral and pharyngeal cancer have been detected: a pattern for the north (including the northern, northeastern and midwestern regions, which are the poorest ones) and a pattern for the south (including the southern and southeastern regions). The southern pattern revealed incidence rates higher than 15 per 100,000 among males, and the northern pattern displayed lower rate levels. Similarly, mortality rates in the south were higher than three per 100,000 and the northern pattern was characterized by lower rates. Other cancers linked to tobacco smoking, such as esophagus, larynx, lung and bladder cancer kept the same pattern of incidence and mortality rates related to oral and pharyngeal cancer in males per region. Information on survival of patients with oral and pharyngeal cancer was very restricted in Brazil, thus hindering the survival analysis per region, but the studies conducted allowed to conclude that the majority of diagnoses were conducted in advanced stages of the disease and implied the low 5-year survival rate observed in Brazil. Tongue tumors displayed the worst survival rates. The southern region shares specific risk factors involved in the oral and pharyngeal cancer present in the Argentinean and Uruguayan populations, namely heavy tobacco smoking and alcohol consumption, as well as high intake of charcoal-grilled red meat and mate. In addition to these risks, part of the oral and pharyngeal cancer registered in Brazil might be linked to a few factors present among people with low life standards, including poor oral hygiene and nutrition.

Exposures in the painting trades and paint manufacturing industry and risk of cancer among men and women in Sweden

Using data from the 1960 and 1970 Swedish censuses and the Swedish Cancer Register for 1971 to 1989, this study investigated variations in cancer risk by gender associated with employment in painting trades and paint manufacturing. Among men, standardized incidence ratios were significantly increased for lung cancer among painters and lacquerers; bladder cancer among artists; and pancreas cancer, lung cancer, and nonlymphocytic leukemia among paint and varnish plant workers. Risks for women were elevated for cancers of the esophagus, larynx, and oral cavity among lacquerers and for oral cancer among glaziers. These findings are consistent with the report of the International Agency for Research on Cancer that classified painting as an occupationally related cause of cancer and provide further evidence that the risk of certain cancers is increased by exposures in the paint manufacturing process.

Risk factors for squamous cell carcinoma of the oral cavity in young people--a comprehensive literature review

There have been several reports of a rising incidence of oral cancer from many parts of the world. Although it is well known that oral cancer increases with age, recent trends for a rising incidence particularly relates to cancer of the tongue and mouth in young males. This review critically examines 46 publications devoted to oral cancer in the young adult. Most studies suggest that 4-6% of oral cancers now occur at ages younger than 40 years. Several studies examining risk factors for oral cancer in the young provide evidence that many younger patients have never smoked or consumed alcohol, which are recognised risk factors in older groups, or that duration of exposure may be too short for malignant transformation to occur. Information on many aspects of aetiology for this disease in the young implicating occupational, familial risk, immune deficits and virus infection are meagre. The spectrum of genetic abnormality disclosed is similar to older patients, there is paucity of specific studies involving younger cohorts, but predisposition to genetic instability has been hypothesised as a likely cause. Conflicting evidence is also reported on the sex distribution and outcome compared with older patients. Much work is required to understand the caveats related to global demography, risk factors and their diagnostic and prognostic markers for this disease which might be considered a disease distinct from that occurring in older patients.

Laryngeal and hypopharyngeal cancers and occupational exposure to formaldehyde and various dusts: a case-control study in France

OBJECTIVES

A case-control study was conducted in France to assess possible associations between occupational exposures and squamous cell carcinomas of the larynx and hypopharynx.

METHODS

The study was restricted to men, and included 201 hypopharyngeal cancers, 296 laryngeal cancers, and 296 controls (patients with other tumour sites). Detailed information on smoking, alcohol consumption, and lifetime occupational history was collected. Occupational exposure to seven substances (formaldehyde, leather dust, wood dust, flour dust, coal dust, silica dust, and textile dust) was assessed with a job exposure matrix. Exposure variables used in the analysis were probability, duration, and cumulative level of exposure. Odds ratios (ORs) with their 95% confidence intervals (95% CIs) were estimated by unconditional logistic regression, and were adjusted for major confounding factors (age, smoking, alcohol, and when relevant other occupational exposures).

RESULTS

Hypopharyngeal cancer was found to be associated with exposure to coal dust (OR 2.31, 95% CI 1.21 to 4.40), with a significant rise in risk with probability (p<0.005 for trend) and level (p<0.007 for trend) of exposure. Exposure to coal dust was also associated with an increased risk of laryngeal cancer (OR 1.67, 95% CI 0.92 to 3.02), but no dose-response pattern was found. A significant relation, limited to hypopharyngeal cancer, was found with the probability of exposure to formaldehyde (p<0.005 for trend), with a fourfold risk for the highest category (OR 3.78, 95% CI 1.50 to 9.49). When subjects exposed to formaldehyde with a low probability were excluded, the risk also increased with duration (p<0.04) and cumulative level of exposure (p<0.14). No significant association was found for any other substance.

CONCLUSION

These results indicate that exposure to formaldehyde and coal dust may increase the risk of hypopharyngeal cancer.

Trichloroethylene and cancer: epidemiologic evidence

Trichloroethylene is an organic chemical that has been used in dry cleaning, for metal degreasing, and as a solvent for oils and resins. It has been shown to cause liver and kidney cancer in experimental animals. This article reviews over 80 published papers and letters on the cancer epidemiology of people exposed to trichloroethylene. Evidence of excess cancer incidence among occupational cohorts with the most rigorous exposure assessment is found for kidney cancer (relative risk [RR] = 1.7, 95% confidence interval [CI] 1.1-2.7), liver cancer (RR = 1.9, 95% CI(1.0-3.4), and non-Hodgkin's lymphoma (RR = 1.5, 95% CI 0.9-2.3) as well as for cervical cancer, Hodgkin's disease, and multiple myeloma. However, since few studies isolate trichloroethylene exposure, results are likely confounded by exposure to other solvents and other risk factors. Although we believe that solvent exposure causes cancer in humans and that trichloroethylene likely is one of the active agents, we recommend further study to better specify the specific agents that confer this risk and to estimate the magnitude of that risk.

Biomarkers and molecular epidemiology and chemoprevention of oral carcinogenesis

Chemopreventives are chemicals that prevent the formation of cancers such as oral cancer. They can take the form of nutrients or synthetic molecules, and their fundamental characteristic is that they do not produce disease processes that would result in debilitating symptoms. Current evidence indicates that they function by modifying the oxidative state of transforming cells. Biomarkers can take the form of genetic and molecular indicators, which characterize the function of chemopreventives and cancer processes such as oral carcinogenesis. Biomarkers cannot provide all the required information for risk assessment or possible activity of the chemopreventives. Other methods, such as epidemiological analyses and techniques, must be used to enhance our understanding of the risk for oral cancer in human populations. One common epidemiologic method, the questionnaire, helps to determine the use and carcinogenic potential of tobacco and alcohol during oral carcinogenesis. Genetic and molecular changes in human patient populations may result in a reduction in the number and function of tumor suppressor genes. If these changes are to be assessed, the tissues (e.g., buccal mucosa) must be accessible and harvested in a reliable and consistent manner for the acquisition of DNA, mRNA, and protein. Oral tissues provide sufficient quantities of these molecules and, under stringent conditions, the quality required for the isolation of these molecular constituents. In conjunction with epidemiologic techniques, various genotypic polymorphisms, such as glutathione-S-transferase (GSTM1) or cytochrome P450 (CYP450A1), have indicated a loss in carcinogen detoxification or the processing of internal growth control signals. Biomarkers are composed of a large diverse group of genetic and molecular structures. Some of these biomarkers are indicators for programmed cell death (PCD), while others describe malignant tumor growth. Many of these classes of molecules are oxidative-responsive (e.g., tumor suppressor p53, Bcl-2, growth factors, immune-derived proteins, and death-inducing molecules) and induce PCD by triggering a cascade of cysteine proteases and regulators (e.g., caspases, death receptors). This pathway results in cell-cycle alterations and DNA fragmentation. It is hoped that a detailed knowledge of the processes involved in malignant transformation will better define the biomarker-screening tools for oral cancer. These tools will enhance our ability to predict the incidence of cancer, detect early malignant change, and quantitate chemoprevention during oral carcinogenesis. Chemopreventives such as the retinoids have already demonstrated their ability to suppress potential malignant changes in pre-malignant oral leukoplakias and decrease the incidence of second head-and-neck cancer primaries. It is our hope that this review will increase investigators' interest in developing new screening and detection systems for oral cancer.

Exposure to high concentrations of nitrosamines and cancer mortality among a cohort of rubber workers

OBJECTIVES

To examine if the occurrence of different cancers was increased among rubber workers, as the highest known exposures of humans to nitrosamines have occurred in the rubber industry.

METHODS

A cohort of 8933 rubber workers (hired after 1 January 1950, still active or retired on 1 January 1981 and employed for at least 1 year in one of five study factories) was followed up for mortality from 1 January 1981 to 31 December 1991. Work histories were reconstructed with routinely documented cost centre codes, which allowed identification by employment in specific work areas. For each cost centre code time and factory specific, semi-quantitative exposures to nitrosamines (three levels: low, medium, high) and other compounds were estimated by industrial hygienists. Rate ratios for medium (RRm) and high (RRh) exposures and 95% confidence intervals (95% CIs) were calculated with Cox's proportional hazards models with the low exposure as reference.

RESULTS

Exposure to nitrosamines was significantly associated with an increased mortality from cancers of the oesophagus (13 deaths: RRm 1.7, 95% CI 0.3 to 10.3; RRh 7.3, 95% CI 1.9 to 27.8) and of the oral cavity and pharynx (17 deaths: RRm 0.8, 95% CI 0.2 to 4.1; RRh 3.9, 95% CI 1.4 to 11.1). A non-significant trend of increasing mortality with exposure to higher concentrations of nitrosamines was found for mortality from cancer of the prostate (26 deaths: RRm 1.4, 95% CI 0.5 to 3.8; RRh 2.2, 95% CI 0.9 to 5.6), and the brain (six deaths: RRm 3.9, 95% CI 0.3 to 42.6; RRh 6.0, 95% CI 0.6 to 57.6). No association was found between exposure to nitrosamines and cancer of the stomach (RRm 0.8, 95% CI 0.4 to 1.8; RRh 1.2, 95% CI 0.5 to 2.5) or lung (RRm 1.0, 95% CI 0.6 to 1.5; RRh 1.0, 95% CI 0.7 to 1.6).

CONCLUSIONS

Exposure to high concentrations of nitrosamines is associated with increased mortality from cancers of the oesophagus, oral cavity, and pharynx, but not with increased mortality from cancers of the stomach or lung.

Cohort mortality study of 57,000 painters and other union members: a 15 year update

OBJECTIVES

To study mortality patterns in the largest existing cohort of painters.

METHODS

15 years of follow up were added to a study of 42,170 painters and 14,316 non-painters based on union records. There were 23,458 deaths, compared with 5313 in the earlier follow up.

RESULTS

Comparisons with the United States population showed significantly increased rates in painters for lung cancer (standardised mortality ratio (SMR) 1.23, 95% confidence interval (95% CI) 1.17 to 1.29), bladder cancer (SMR 1.23, 95% CI 1.05 to 1.43), liver cancer (SMR 1.25, 95% CI 1.03 to 1.50), and stomach cancer (SMR 1.39, 95% CI 1.20 to 1.59). However, in direct comparisons with non-painters only the excesses for lung cancer (SRR 1.23, 95% CI 1.11 to 1.35, increasing to 1.32, 95% CI 16 to 1.93 with 20 years latency) and bladder cancer (SRR 1.77, 95% CI 1.13 to 2.77) were confirmed. Some confounding by smoking may affect these two outcomes, particularly with external referents. Cirrhosis of the liver was increased for both painters and non-painters (SMRs 1.21, 95% CI 1.07 to 1.35, and 1.26, 95% CI 1.03 to 1.51, respectively), possibly indicating high alcohol consumption. Suicide (SMR 1.21, 95% CI 1.05 to 1.38) and homicide (SMR 1.36, 95% CI 1.04 to 1.75) were increased for painters but not for non-painters; neuropsychiatric diseases have been associated with painters in earlier studies.

CONCLUSIONS

The results suggest modest occupational risks for lung and bladder cancer; these results are consistent with existing publications. The International Agency for Research on Cancer has classified painting as an occupation definitely associated with cancer.

Cancer risk in the rubber industry: a review of the recent epidemiological evidence

OBJECTIVES

To examine the recent epidemiological evidence on cancer risk among workers in the rubber industry.

METHODS

Epidemiological studies published after the last detailed review by the International Agency for Research on Cancer (IARC) in 1982 were reviewed. 12 cohort studies in nine countries that examined distinct populations of workers in the rubber industry, seven industry based nested case-control studies, 48 community based case-control studies in 16 countries, and 23 studies based on administrative data that reported risks for employment in the rubber industry were identified.

RESULTS

Excess risks of bladder cancer, lung cancer, and leukaemia were found in most studies, with risks above 1.5 in about half of the studies. A moderate excess risk for laryngeal cancer was consistent across studies. Excess risks were found in a few studies for cancers of the oesophagus, stomach, colon, liver, pancreas, skin, prostate, kidney, brain, and thyroid, and for malignant lymphoma and multiple myeloma, but overall results were not consistent for these neoplasms.

CONCLUSIONS

Magnitude of the observed risks varied considerably between studies, but overall the findings indicate the presence of a widespread moderate increased cancer risk among rubber workers. The most consistent results were for bladder, laryngeal, and lung cancer and for leukaemia. Excess risks were also found for other neoplasms but an evaluation of the consistency of the findings is difficult because of the possible selective reporting of results. Recent studies do not provide information associating specific exposures with cancer risk. The preventive measures taken in the rubber industry in recent years may decrease risks, but this has not been documented yet in epidemiological studies.

Laryngeal and hypopharyngeal cancer and occupation: results of a case control-study

OBJECTIVES

To ascertain whether certain occupations are associated with laryngeal or hypopharyngeal cancer.

METHODS

A hospital based case-control study was carried out in 15 hospitals in France. It included 528 male cases diagnosed between January 1989 and April 1991, and 305 male controls with various other types of cancer. Interviews were carried out to obtain lifetime job histories and information on potential confounders. Logistic regression was used to compute the odds ratios (OR) for each of about 80 occupations and industries.

RESULTS

There was an excess risk of laryngeal and hypopharyngeal cancer among service workers (OR 2.2, 95% confidence interval (95% CI) 1.3 to 3.9), agricultural and animal husbandry workers (OR 1.6, 95% CI 0.9 to 2.8), miners and quarrymen (OR 2.0, 95% CI 0.9 to 4.3), plumbers and pipe fitters (OR 2.6, 95% CI 0.8 to 8.1), glass formers and potters (OR 4.3, 95% CI 1.0 to 18) transport equipment operators (OR 1.5, 95% CI 1.0 to 2.5), and unskilled workers (OR 1.7, 95% CI 1.0 to 2.9). Analysis by industrial branch showed an excess risk for coal mining (OR 2.1, 95% CI 1.1 to 4.1), manufacture of metal products (OR 1.9, 95% CI 1.0 to 3.3), and administration and sanitary services (OR 1.7, 95% CI 1.1 to 2.5).

CONCLUSION

These results suggest that occupational exposure might have a role in generating laryngeal and hypopharyngeal cancer, and indicate the need for further evaluation of these findings, an for the identification of the carcinogens which might account for the excess risks found for certain occupations.

Cancer mortality among workers in the German rubber industry: 1981-91

OBJECTIVES

To determine the cancer specific mortality of active and retired workers of the German rubber industry with emphasis on cancer sites which have been associated with the rubber industry in previous studies.

METHODS

A cohort of 11,663 German men was followed up for mortality from 1 January 1981 to 31 December 1991. Cohort members were active (n = 7536) or retired (n = 4127) at the beginning of the study, and had been employed for at least one year in one of five study plants producing types or general rubber goods. Vital status was ascertained for 99.7% of the cohort members, and cause of death found for 96.8% of the 2719 decedents. Age and calendar year adjusted standardised mortality ratios (SMR) and 95% confidence intervals (95% CI) were calculated overall from national reference rates and stratified by year of hire and by years since hire.

RESULTS

Mortalities from all causes (SMR 108; 95% CI 104-112) and all cancers (SMR 111; 95% CI 103-119) were significantly increased in the study cohort. Significant excesses in the mortalities from lung cancer (SMR 130; 95% CI 115-147) and pleural cancer (SMR 401; 95% CI 234-642) were identified. SMRs higher than 100 were found for cancers of the pharynx (SMR 144; 95% CI 76-246), oesophagus (SMR 120; 95% CI 74-183), stomach (SMR 110; 95% CI 86-139), rectum (SMR 123; 95% CI 86-170), larynx (SMR 129; 95% CI 69-221), prostate (SMR 108; 95% CI 84-136), and bladder (SMR 124; 95% CI 86-172), as well as for leukaemia (SMR 148; 95% CI 99-213). Mortalities from liver cancer, brain cancer, and lymphoma were lower than expected.

CONCLUSIONS

Mortalities from cancer of several sites previously associated with the rubber industry were also increased among workers of the German rubber industry. Results of the stratified analyses are consistent with a role of occupational exposure in the aetiology of some of these cancers.

Cancer incidence among waitresses in Norway

Previous studies have found high risk of cancers of the upper aerogastric tract, liver, and lung among waiters. Since approximately 75 percent of those working in the restaurant business in Norway are women, we have analyzed cancer incidence in a cohort of waitresses, to determine whether they have the same high cancer-risk as their male colleagues. The cohort consisted of 5,314 waitresses organized in the Restaurant Workers' Union between 1932 and 1978. The follow-up period was from 1959 to 1991. The standardized incidence ratio (SIR) for all causes of cancer was 1.0 (95 percent confidence interval [CI] = 0.9-1.1), based on 430 observed cases. Cancers of the tongue, mouth, pharynx, larynx, esophagus, and liver were grouped together as alcohol-associated cancers. SIR for these cancers combined was 1.1 (CI = 0.5-2.2). For lung cancer, SIR was 2.3 (CI = 1.6-3.1). Cervical cancer was also more frequent than expected, and breast cancer less frequent than expected. The larger excess of lung cancer and cervical cancer appeared in the sub-cohort working in restaurants with a license to serve alcohol. No excess risk of alcohol-associated cancers could be detected in this cohort of Norwegian waitresses. A longer follow-up period will be necessary to evaluate possible consequences of an increased alcohol consumption among younger waitresses. Waitresses in Norway are, like their male colleagues, at high risk for lung cancer.

Incidence of cancer among male waiters and cooks: two Norwegian cohorts

Previous occupational survey studies have identified 'waiter' and 'cook' as possible high risk occupations for cancer. However, few cohort studies have been performed among persons in the restaurant business, and we therefore have analyzed cancer incidence in two cohorts of Norwegian waiters and cooks. The cohorts consisted of skilled male workers, 1,463 waiters and 2,582 cooks, who received their craft certificate between 1958 and 1983. The cohorts were followed from 1959 through 1991. The standardized incidence ratio (SIR) for all causes of cancer was 1.4 (95 percent confidence interval [CI] = 1.2-1.7] for waiters, and 1.1 (CI = 0.9-1.4) for cooks. Cancers of the tongue, mouth, pharynx, larynx, esophagus, and liver were grouped together as alcohol-associated cancers. SIR for these cancers combined was 5.1 (CI = 3.4-7.4) for waiters and 4.2 (CI = 2.2-7.2) for cooks. For lung cancer, SIR was 2.0 (CI = 1.3-2.9) for waiters and 0.7 (CI = 0.2-1.7) for cooks. For alcohol-associated cancers, the analysis carried out according to number of years since first employment showed a larger number of cases than expected for both occupations in all time-periods. The excess of lung cancer cases among waiters appeared after 30 years or more of employment. The study shows that waiters and cooks are at high risk of cancers associated with alcohol consumption, and that waiters, in addition, show high rates for lung cancer. The hypothesis of an occupational lung-cancer risk in cooks was not supported by this study.

Tobacco smoking, alcohol drinking, and cancer of the oral cavity and oropharynx among U.S. veterans

BACKGROUND

Independent carcinogenic effects of alcohol drinking and tobacco smoking as well as their interaction can be usefully studied in a population of heavy drinkers and smokers.

METHODS

A hospital-based case-control study was conducted during 1972 to 1983 in a large Veterans hospital in East Orange, New Jersey. A total of 359 oral cavity-oropharynx cancer cases and 2280 controls were interviewed according to tobacco smoking, use of smokeless tobacco, alcoholic beverage, coffee and tea drinking, race, family origin, religion, and occupation as bartender.

RESULTS

Odds ratio of oral cancer increased up to the level of 35 cigarettes per day and 21 whiskey equivalents per day: no further increase was found for higher level of exposure to either factor. A protective effect of quitting smoking was found, but the number of former smokers was small. No difference occurred in oral cancer risk according to type of alcoholic beverage drunk. An interaction effect compatible with a multiplicative model was found between the two exposures. Blacks were at lower risk than whites, and, in the latter group, individuals of Italian origin were at lower risk than individuals from northern or central European countries.

CONCLUSIONS

Alcohol drinking and tobacco smoking were responsible for the majority of oral cancer cases in this population of US Veterans.