Occupational asbestos exposure as a risk factor for laryngeal carcinoma in a population-based case-control study from Germany

Plants, Microorganisms and Their Metabolites in Supporting Asbestos Detoxification-A Biological Perspective in Asbestos Treatment

Many countries banned asbestos due to its toxicity, but considering its colossal use, especially in the 1960s and 1970s, disposing of waste containing asbestos is the current problem. Today, many asbestos disposal technologies are known, but they usually involve colossal investment and operating expenses, and the end- and by-products of these methods negatively impact the environment. This paper identifies a unique modern direction in detoxifying asbestos minerals, which involves using microorganisms and plants and their metabolites. The work comprehensively focuses on the interactions between asbestos and plants, bacteria and fungi, including lichens and, for the first time, yeast. Biological treatment is a prospect for in situ land reclamation and under industrial conditions, which can be a viable alternative to landfilling and an environmentally friendly substitute or supplement to thermal, mechanical, and chemical methods, often characterized by high cost intensity. Plant and microbial metabolism products are part of the green chemistry trend, a central strategic pillar of global industrial and environmental development.

Trend and projection of larynx cancer incidence and mortality in China from 1990 to 2044: A Bayesian age-period-cohort modeling study

BACKGROUND

Larynx cancer is one of the most common cancers in head and neck, and imposes heavy burden on individual and societies. A comprehensive understanding of the burden of larynx cancer is necessary to improve prevention and control strategies. However, the secular trend of larynx cancer incidence and mortality in China remains unclear.

METHODS

The incidence and deaths rates of larynx cancer from 1990 to 2019 were collected from the Global Burden of Disease Study 2019 database. The temporal trend of larynx cancer was analyzed using a joinpoint regression model. The age-period-cohort model was used to explore the age, period, and cohort effects on larynx cancer and predict future trends up to 2044.

RESULTS

From 1990 to 2019, the age-standardized incidence rate of larynx cancer in China increased by 1.3% (95% CI 1.1 to 1.5) in males, but decreased by 0.5% (95% CI -0.1 to 0) in females. The age-standardized mortality rate of larynx cancer in China decreased by 0.9% (95% CI -1.1 to -0.6) and 2.2% (95% CI -2.8 to -1.7) in males and females, respectively. Among the four risk factors, smoking and alcohol use contributed to a heavier burden compared to occupational exposure to asbestos and sulfuric acid with respect to mortality. Age effects showed that the incidence and deaths of larynx cancer were concentrated in people older than 50 years old. Period effects exerted the most significant effect on larynx cancer incidence for males. In terms of cohort effects, people born in the earlier cohorts presented a higher risk of larynx cancer compared with the later cohorts. From 2020 to 2044, the age-standardized incidence rates of larynx cancer continued to increase in males, whereas the age-standardized mortality rates continued to decrease in both males and females.

CONCLUSION

The burden of larynx cancer in China has a significant gender difference. The age-standardized incidence rates will continue to increase in males up to 2044. The disease pattern and risk factors of larynx cancer should be comprehensively studied to promote the development of timely intervention measures and relieve the burden effectively.

Esophageal and Head and Neck Cancer Patients Attending Ocean Road Cancer Institute in Tanzania from 2019 to 2021: An Observational Study

BACKGROUND

Cancer in Africa is an emerging public health problem that needs urgent preventive measures, particularly in workplaces where exposure to carcinogens may occur. In Tanzania, the incidence rate of cancer and mortality rates due to cancers are increasing, with approximately 50,000 new cases each year. This is estimated to double by 2030.

METHODS

Our hospital-based cross-sectional study describes the characteristics of newly diagnosed patients with head and neck or esophageal cancer from the Ocean Road Cancer Institute (ORCI), Tanzania. We used an ORCI electronic system to extract secondary data for these patients.

RESULTS

According to the cancer registration, there were 611 head and neck and 975 esophageal cancers recorded in 2019-2021. Two-thirds of these cancer patients were male. About 25% of the cancer patients used tobacco and alcohol, and over 50% were involved in agriculture.

CONCLUSION

Descriptions of 1586 head and neck cancer patients and esophageal cancer patients enrolled in a cancer hospital in Tanzania are given. The information may be important for designing future studies of these cancers and may be of value in the development of cancer prevention measures.

Association of SIRT1 single gene nucleotide polymorphisms and serum SIRT1 levels with laryngeal squamous cell carcinoma patient survival rate

BACKGROUND

SIRT1 is a multifunctional protein, possibly essential in tumorigenesis pathways, which can act both as a tumor promoter and tumor suppressor depending on the oncogenes, specific to particular tumors. Pathogenesis of laryngeal cancer is multifactorial and the association of SIRT1 expression with the clinical characteristics and prognosis of LSCC has not been fully identified.

OBJECTIVES

The study aimed to evaluate associations between single gene nucleotide polymorphisms (SNPs) of SIRT1 (rs3818292, rs3758391, and rs7895833), serum SIRT1 levels, and 5-year survival rate in patients with laryngeal squamous cell carcinoma (LSCC).

METHODS

The study involved 302 patients with LSCC and 409 healthy control subjects. The genotyping of SNPs was performed using RT-PCR, and serum SIRT1 levels were determined by the ELISA method.

RESULTS

Our study found significant differences in genotype distributions of SIRT1 rs3758391 polymorphisms between the study groups. SIRT1 rs3758391 T/T genotype was associated with the increased LSCC development odds (OR = 1.960 95% CI = 1.028-3.737; p= 0.041). Carriers of SIRT1 rs3758391 T/T genotype had statistically significantly increased odds of LSCC development into advanced stages under the codominant and recessive genetic models (OR = 2.387 95% CI = 1.091-5.222; p= 0.029 and OR = 2.287 95% CI = 1.070-4.888; p= 0.033, respectively). There were no statistically significant differences in serum SIRT1 levels between the LSCC and control groups. However, LSCC patients with SIRT1 rs3818292 AG genotype demonstrated a tendency to significantly lower SIRT1 serum levels than controls (p= 0.034). No statistically significant associations between SIRT1 (rs3818292, rs3758391, and rs7895833) SNPs and the 5-year survival rate of LSCC patients were found.

CONCLUSION

The present study indicated a statistically significant association between the SIRT1 rs3758391 T/T genotype and increased LSCC development odds. LSCC patients with SIRT1 rs3818292 AG genotype showed a tendency to manifest with lower SIRT1 serum levels. No associations between SIRT1 SNPs and the 5-year survival rate of LSCC patients were detected.

Could Primary Chemoradiotherapy in T2 Glottic Cancers Yield Results Comparable to Primary Radiotherapy in T1? Considerations from 531 German Early Stage Patients

T1 glottic cancer is a highly treatable disease with local control (LC) rates over 90% by either primary radiotherapy (pRT) or transoral laser microsurgery (TLM). LC of T2 glottic cancers is 15 percent points poorer on average. However, salvage after pRT entails more than 50% total laryngectomy. Therefore, there is a need for enhanced LC. Altered fractionation regimens improved LC in T1 but not in T2. For this reason, for T2, alternative strategies must be considered. In a large observational cohort study including 531 early-stage laryngeal cancers, a small number of patients were treated with primary chemoradiotherapy (pCRT). In multivariable analysis, factors associated with significantly poorer outcomes included age, comorbidities, supraglottic localization, and T category. While there was a significant difference between pRT and surgery (HR 1.79; 95%-CI: 1.15-2.79), there was none between pCRT and surgery (HR 0.70; 95%-CI: 0.33-1.51). There is evidence from the literature that pCRT in early glottic cancers could yield results that surpass the limits so far experienced in radiotherapy alone with acceptable toxicity. Thus, prospective randomized studies with larger numbers of patients are warranted.

Global burden of larynx cancer, 1990-2017: estimates from the global burden of disease 2017 study

Larynx cancer is one of the most common cancers in head and neck. This study aimed to investigate the health burden of larynx cancer at global, regional, and national levels. We collected data of larynx cancer between 1990 and 2017 from the Global Burden of Disease study, including incidence, mortality, and disability adjusted life-years (DALYs). Estimated annual percentage changes (EAPCs) were calculated to assess the changes in age-standardized rate (ASR) of larynx cancer. From 1990 to 2017, LC incident cases increased by 58.67%; however, age-standardized incidence rate (ASIR) decreased, with an EAPC of -0.99. Additionally, the incident cases and ASIR of LC were 6-fold higher for male than those for female in 2017. Over the past 28 years, deaths and DALYs of larynx cancer increased by 33.84% and 25%. Contrarily, age-standardized death and DALY rate showed a downward trend. Incidence, death, and DALYs of larynx cancer were always the highest in people aged 50-69 years. Overall, all the ASRs showed downward trends globally. The majority of larynx cancer burden was observed in men, especially among male aged 50-69 years. South and East Asia carried the heaviest burden of larynx cancer worldwide.

Laryngeal Cancer Risks in Workers Exposed to Lung Carcinogens: Exposure-Effect Analyses Using a Quantitative Job Exposure Matrix

INTRODUCTION

Various established occupational lung carcinogens are also suspected risk factors for laryngeal cancer. However, individual studies are often inadequate in size to investigate this relatively rare outcome. Other limitations include imprecise exposure assessment and inadequate adjustment for confounders.

METHODS

This study applied a quantitative job exposure matrix (SYN-JEM) for four established occupational lung carcinogens to five case-control studies within the International Head and Neck Cancer Epidemiology Consortium. We used occupational histories for 2256 laryngeal cancer cases and 7857 controls recruited from 1989 to 2007. We assigned quantitative exposure levels for asbestos, respirable crystalline silica, chromium-VI, and chromium-VI and nickel combined (to address highly correlated exposures) via SYN-JEM. We assessed effects of occupational exposure on cancer risk for males (asbestos, respirable crystalline silica, chromium-VI, and chromium-VI and nickel combined) and females (asbestos and respirable crystalline silica), adjusting for age, study, tobacco smoking, alcohol consumption, and asbestos exposure where relevant.

RESULTS

Among females, odds ratios (ORs) were increased for ever versus never exposed. Among males, P values for linear trend were <0.05 for estimated cumulative exposure (all agents) and <0.05 for exposure duration (respirable crystalline silica, chromium-VI, and chromium-VI and nickel combined); strongest associations were for asbestos at >90th percentile cumulative exposure (OR = 1.3, 95% confidence interval [CI] = 1.0, 1.6), respirable crystalline silica at 30+ years duration (OR = 1.4, 95% CI = 1.2, 1.7) and 75th-90th percentile cumulative exposure (OR = 1.4, 95% CI = 1.1, 1.8), chromium-VI at >75th percentile cumulative exposure (OR = 1.9, 95% CI = 1.2, 3.0), and chromium-VI and nickel combined at 20-29 years duration (OR = 1.5, 95% CI = 1.1, 2.2).

CONCLUSIONS

These findings support hypotheses of causal links between four lung carcinogens (asbestos, respirable crystalline silica, chromium-VI, and nickel) and laryngeal cancer.

Work-related laryngeal cancer: Trends in France from 2001 to 2016

OBJECTIVES

As part of the 2014-2019 cancer plan and in order to improve our knowledge of work-related cancers, we analysed the work-related laryngeal cancer risk situations identified in the French national occupational disease surveillance and prevention network (rnv3p) from 2001 to 2016.

MATERIAL AND METHODS

This study focused on cases of work-related laryngeal cancer, which the expert physician considered to be directly related to exposure (intermediate or strong causal relationship). Demographic data, occupational exposure circumstances (hazards, occupation, business sector), non-occupational risk factors and the occupational physician's opinion concerning notification as an occupational disease were analysed.

RESULTS

Two hundred forty-four cases of laryngeal cancer were registered between 2001 and 2016. One hundred and forty seven cases were considered to be work-related, with an intermediate or strong causal relationship in 87 cases. This exclusively male population had a median age of 59 years. Ninety-seven different forms of exposure were identified, including asbestos in 78 cases. The main business sectors concerned were specialized construction (14 cases) and metallurgy (7 cases). Occupational disease notification was recommended in 60 patients, corresponding to asbestos exposure in 80% of cases.

CONCLUSIONS

Asbestos is the laryngeal cancer risk factor most commonly reported in the network from 2001 to 2016. This study confirms the role of asbestos in laryngeal carcinogenesis. Laryngeal cancer may therefore need to be compensated as an occupational disease in France, as in other European countries.

Recent Scientific Evidence Regarding Asbestos Use and Health Consequences of Asbestos Exposure

To justify the continuous use of two million tons of asbestos every year, it has been argued that a safe/controlled use can be achieved. The aim of this review was to identify recent scientific studies that present empirical evidence of: 1) health consequences resulting from past asbestos exposures and 2) current asbestos exposures resulting from asbestos use. Articles with evidence that could support or reject the safe/controlled use argument were also identified. A total of 155 articles were included in the review, and 87 % showed adverse asbestos health consequences or high asbestos exposures. Regarding the safe/controlled use, 44 articles were identified, and 82 % had evidence suggesting that the safe/controlled use is not being achieved. A large percentage of articles with evidence that support the safe/controlled use argument have a conflict of interest declared. Most of the evidence was developed in high-income countries and in countries that have already banned asbestos.

The joint effect of asbestos exposure, tobacco smoking and alcohol drinking on laryngeal cancer risk: evidence from the French population-based case-control study, ICARE

OBJECTIVE

The objective of the study was to investigate the joint effect of occupational exposure to asbestos, and tobacco and alcohol consumption, on the risk of laryngeal cancer among men.

METHODS

We used data from a large population-based case-control study conducted in France. We estimated two-way and three-way interactions between asbestos exposure (never vs ever exposed), tobacco consumption (<20 vs. ≥20 pack-years) and alcohol consumption (<5 vs. ≥5 drinks per day). The interaction on an additive scale was assessed by estimating the relative excess risk due to interaction (RERI) and the attributable proportion due to interaction, and the interaction on a multiplicative scale was assessed by estimating the multiplicative interaction parameter (ψ). Multiplicative interactions were also assessed using fractional polynomials for alcohol drinking, tobacco smoking and asbestos exposure.

RESULTS

When compared with light-to-moderate smokers and drinkers never exposed to asbestos, the increase in laryngeal cancer risk was smallest among light-to-moderate drinkers and smokers exposed to asbestos (OR=2.23 (1.08 to 4.60)), and highest among heavy smokers and drinkers ever exposed to asbestos (OR=69.39 (35.54 to 135.5)). We found an additive joint effect between asbestos exposure and alcohol consumption (RERI=4.75 (-4.29 to 11.12)), whereas we observed a more than additive joint effect between asbestos exposure and tobacco consumption (RERI=8.50 (0.71 to 23.81)), as well as between asbestos exposure, and tobacco and alcohol consumption (RERI=26.57 (11.52 to 67.88)). However, our results did not suggest any interaction on a multiplicative scale.

CONCLUSIONS

Our results suggest that asbestos exposure, in combination with tobacco and alcohol exposure, accounted for a substantial number of laryngeal cancer cases. Our findings therefore highlight the need for prevention in activities, such as construction work, where exposure to asbestos-containing materials remains.

Occupation and educational inequalities in laryngeal cancer: the use of a job index

BACKGROUND

Previous studies tried to assess the association between socioeconomic status and laryngeal cancer. Alcohol and tobacco consumption explain already a large part of the social inequalities. Occupational exposures might explain a part of the remaining but the components and pathways of the socioeconomic contribution have yet to be fully disentangled. The aim of this study was to evaluate the role of occupation using different occupational indices, differentiating between physical, psycho-social and toxic exposures and trying to summarize the occupational burden into one variable.

METHODS

A population-based case-control study conducted in Germany in 1998-2000 included 208 male cases and 702 controls. Information on occupational history, smoking, alcohol consumption and education was collected with face-to-face interviews. A recently developed job-classification index was used to account for the occupational burden. A sub-index focussed on jobs involving potentially carcinogenic agents (CAI) for the upper aero digestive tract.

RESULTS

When adjusted for smoking and alcohol consumption, higher odds ratios (ORs) were found for lower education. This OR decreased after further adjustment using the physical and psycho-social job indices (OR = 3.2, 95%-CI: 1.5-6.8), similar to the OR using the sub-index CAI (OR = 3.0, 95%-CI: 1.4-6.5).

CONCLUSIONS

The use of an easily applicable control variable, simply constructed on standard occupational job classifications, provides the possibility to differentiate between educational and occupational contributions. Such an index might indirectly reflect the effect of carcinogenic agents, which are not collected in many studies.

Laryngeal cancer and silica dust exposure: a systematic review and meta-analysis

BACKGROUND

Individual epidemiological studies generally lack the power to examine the association between silica exposure or silicosis and laryngeal cancer. We summarized pertinent evidence from published literature by using meta-analysis.

METHODS

A systematic literature search was performed to identify cohort and case-control studies, and the method of meta-analysis was used to combine standardized mortality ratios (SMRs) or standardized incidence ratios (SIRs) from cohort studies and odds ratios (ORs) from case-control studies.

RESULTS

A significantly increased risk of laryngeal cancer (pooled OR = 1.39, 95% confidence interval (95% CI): 1.17-1.67) among workers exposed to silica dust was observed by combining six case-control studies with adjustment for smoking and alcohol consumption. A similarly increased but statistically non-significant risk estimate was observed from cohort studies, with a pooled SMR of 1.38 (95% CI: 0.79-1.96) for silicosis cases; and a pooled SMR of 1.13 (95% CI: 0.82-1.45) and a pooled SIR of 1.50 (95% CI: 0.59-2.42) for workers with silica dust exposure.

CONCLUSION

This systematic review demonstrated a weak association between silica or silicosis and laryngeal cancer. Owing to the inherent limitations of the original studies, interpretation of the results of this meta-analysis should be cautious.

Factors predicting survival after diagnosis of laryngeal cancer

Survival in patients with laryngeal cancer has not increased remarkably within the last years. It is presumed that a variety of factors act jointly in predicting survival after diagnosis: tumour stage, tumour site, treatment approaches, age and comorbidities. The aim of this German clinical multi-centre study is to present results from multivariate analysis. A retrospective cohort study was conducted in four hospitals in South-West Germany. Incident cases with laryngeal squamous cell carcinoma were included for the years 1998 to 2004, resulting in a population sample of 594 patients. Multivariate regression analysis was performed using the Cox proportional hazards model. Patients were followed up for 64.1months on average. Overall 5-year survival was 66% (95% confidence interval (CI): 62-70%). The strongest risk factors in multivariate analysis were age at first diagnosis (hazard ratio (HR): 1.5; 95% CI: 1.5-1.7 per each additional 10years), tumour stage, and the development of recurrences (HR 3.1; 95% CI: 2.3-4.2) or second primary carcinomas (HR 2.1; 95% CI: 1.4-3.1). A somewhat weaker effect was shown for patients with comorbidities (using Charlson's comorbidity index). The choice of treatment did not strongly affect survival when adjusting for other factors, possibly because the optimal treatment approach was applied for the specific constitution and requirements of each patient. For future research it would be desirable to study the effect of treatment on quality of life in multivariate analysis as well as other modifiable risk factors as smoking and drinking reduction or cessation after diagnosis.