Mobile phone use and risk of uveal melanoma: results of the risk factors for uveal melanoma case-control study

Parental occupational exposure to solvents and risk of developing testicular germ cell tumors among sons: a French nationwide case-control study (TESTIS study)

OBJECTIVES

The etiology of testicular germ cell tumors (TGCT) is suspected to be related to prenatal environmental risk factors. Some solvents have potential endocrine disrupting or carcinogenic properties and may disrupt male genital development in utero. The aim of this study was to examine the association between parental occupational exposure to solvents and TGCT risk among their offspring.

METHODS

A French nationwide case-control study, TESTIS included 454 TGCT cases and 670 controls frequency-matched on region and 5-year age strata. Participants were interviewed via telephone and provided information on parental occupations at birth. Job-exposure matrices (JEM) developed in the French Matgéné program were used to assign exposure to five petroleum-based solvents, five solvents or groups of oxygenated solvents, and five chlorinated solvents. Odds ratios (OR) for TGCT and 95% confidence intervals (CI) were estimated using conditional logistic regression, adjusting for TGCT risk factors.

RESULTS

Occupational exposure to at least one solvent during the year of their son's birth was 41% among fathers and 21% among mothers. Paternal exposure to at least one solvent showed OR 0.89 (95% CI 0.68-1.15). Exposure to perchloroethylene (OR 1.41, 95% CI 0.55-3.61), methylene chloride (OR 1.13, 95% CI 0.54-2.34) and diesel/kerosene/fuel oil (OR 1.17, 95% CI 0.80-1.73) disclosed OR >1 but with low precision. Our results suggest a possible modest increase in non-seminoma risk for sons whose fathers were highly exposed to trichloroethylene (OR 1.44, 95% CI 0.79-2.63). Maternal exposure to at least one solvent showed OR 0.90 (95% CI 0.65-1.24). When stratifying by birth year, men born in the 1970s experienced an increased TGCT risk following maternal exposure to fuels and petroleum-based solvents (OR 2.74, 95% CI 1.11-6.76).

CONCLUSION

Overall, no solid association was found between parental occupational exposure to solvents and TGCT risk. The association found with maternal occupational exposure to fuels and petroleum solvents among older men needs further investigation.

Testicular germ cell tumour risk by occupation and industry: a French case-control study - TESTIS

OBJECTIVE

Testicular germ cell tumours (TGCT) are the most common cancer in men of working age and its incidence has increased notably over the past 40 years. Several occupations have been identified as potentially associated with TGCT risk. The aim of this study was to further explore the relationship between occupations, industries and TGCT risk in men aged 18-45 years.

METHODS

The TESTIS study is a multicenter case-control study conducted between January 2015 and April 2018 in 20 of 23 university hospital centers in metropolitan France. A total of 454 TGCT cases and 670 controls were included. Full job histories were collected. Occupations were coded according to the International Standard Classification of Occupation 1968 version (ISCO-1968) and industry according to the 1999 version of Nomenclature d'Activités Française (NAF-1999). For each job held, ORs and 95% CIs were estimated using conditional logistic regression.

RESULTS

A positive association was observed between TGCT and occupation as agricultural, animal husbandry worker (ISCO: 6-2; OR 1.71; 95% CI (1.02 to 2.82)), as well as salesman (ISCO: 4-51; OR 1.84; 95% CI (1.20 to 2.82)). An increased risk was further observed among electrical fitters and related, electrical and electronics workers employed for 2 years or more (ISCO: 8-5; OR≥2 years 1.83; 95% CI (1.01 to 3.32)). Analyses by industry supported these findings.

CONCLUSIONS

Our findings suggest that agricultural, electrical and electronics workers, and salesmen workers experience an increased risk of TGCT. Further research is needed to identify the agents or chemicals in these high-risk occupations which are relevant in the TGCT development.

TRIAL REGISTRATION NUMBER

NCT02109926.

Cellular Telephone Use and the Risk of Brain Tumors: Update of the UK Million Women Study

BACKGROUND

The ongoing debate of whether use of cellular telephones increases the risk of developing a brain tumor was recently fueled by the launch of the fifth generation of wireless technologies. Here, we update follow-up of a large-scale prospective study on the association between cellular telephone use and brain tumors.

METHODS

During 1996-2001, 1.3 million women born in 1935-1950 were recruited into the study. Questions on cellular telephone use were first asked in median year 2001 and again in median year 2011. All study participants were followed via record linkage to National Health Services databases on deaths and cancer registrations (including nonmalignant brain tumors).

RESULTS

During 14 years follow-up of 776 156 women who completed the 2001 questionnaire, a total of 3268 incident brain tumors were registered. Adjusted relative risks for ever vs never cellular telephone use were 0.97 (95% confidence interval = 0.90 to 1.04) for all brain tumors, 0.89 (95% confidence interval = 0.80 to 0.99) for glioma, and not statistically significantly different to 1.0 for meningioma, pituitary tumors, and acoustic neuroma. Compared with never-users, no statistically significant associations were found, overall or by tumor subtype, for daily cellular telephone use or for having used cellular telephones for at least 10 years. Taking use in 2011 as baseline, there were no statistically significant associations with talking for at least 20 minutes per week or with at least 10 years use. For gliomas occurring in the temporal and parietal lobes, the parts of the brain most likely to be exposed to radiofrequency electromagnetic fields from cellular telephones, relative risks were slightly below 1.0.

CONCLUSION

Our findings support the accumulating evidence that cellular telephone use under usual conditions does not increase brain tumor incidence.

Unique Geospatial Accumulations of Uveal Melanoma

PURPOSE

The main purpose of this paper was to describe the unique accumulation of cases of uveal melanoma (UM). All patients were white and did not have known occupational risk factors. From the authors' standpoint, there were no lifestyle factors in common in the reported cases. Results of more extensive analyses, including geospatial analysis, are currently being conducted and will be presented in a separate paper.

DESIGN

Observational case series.

METHODS

Descriptive data from medical records, patient interviews, and questionnaires were obtained from 5 patients from North Carolina, 6 patients from Alabama, and 14 patients from New York. Standard incidence ratio (SIR) calculations were provided by the respective states' cancer registries. UM is the most common primary malignant eye tumor in adults, although it is rare, with 2,500 cases diagnosed annually in the United States. Despite a growing understanding of the molecular characteristics, there remains uncertainty regarding epidemiologic trends and environmental risk factors. This study identified 3 geographic accumulations of UM: 1) Huntersville, NC; 2) Auburn, AL; and 3) Broome and Tioga Counties, New York. Investigation of these groups will guide ongoing efforts to discover potential risk factor and assist with future treatment and prevention.

RESULTS

In North Carolina, 5 females who were identified as living in Huntersville, NC, were diagnosed with UM at ages 20, 22, 24, 30, and 31. The SIR calculations considering the observed and expected incidence ratios was 0.7 (95% confidence interval [CI], 0.5-0.9) in Mecklenburg County. In Alabama, 6 individuals who were identified as either attending Auburn University or employed there from 1989 to 1993 had diagnoses of UM. Initial SIR calculations for white females of all ages was 1.15 (95% CI, 0.989-1.328). In New York, SIR for Broome and Tioga counties were 0.93 and not significant. However, in Tioga county, for males and females and females alone, SIRs were 2.00 (P = .04) and 3.33 (P = .006).

CONCLUSIONS

Although most of the conclusions that the SIR does not meet statistical criteria that defines these accumulations as true "cancer clusters," considering the incidence and demographics of UM, these accumulations of cases is unexpected and worth additional exploration. Further investigation into these cases with additional geospatial analyses and blood and tumor testing is ongoing. Information learned from the study of these unique populations may inform a better understanding of the pathogenesis of UM.

Cellular Phone Use and Risk of Tumors: Systematic Review and Meta-Analysis

We investigated whether cellular phone use was associated with increased risk of tumors using a meta-analysis of case-control studies. PubMed and EMBASE were searched from inception to July 2018. The primary outcome was the risk of tumors by cellular phone use, which was measured by pooling each odds ratio (OR) and its 95% confidence interval (CI). In a meta-analysis of 46 case-control studies, compared with never or rarely having used a cellular phone, regular use was not associated with tumor risk in the random-effects meta-analysis. However, in the subgroup meta-analysis by research group, there was a statistically significant positive association (harmful effect) in the Hardell et al. studies (OR, 1.15-95% CI, 1.00 to 1.33- n = 10), a statistically significant negative association (beneficial effect) in the INTERPHONE-related studies (case-control studies from 13 countries coordinated by the International Agency for Research on Cancer (IARC); (OR, 0.81-95% CI, 0.75 to 0.89-n = 9), and no statistically significant association in other research groups' studies. Further, cellular phone use with cumulative call time more than 1000 h statistically significantly increased the risk of tumors. This comprehensive meta-analysis of case-control studies found evidence that linked cellular phone use to increased tumor risk.

Iris Colour and the Risk of Developing Uveal Melanoma

Uveal melanoma (UM) is a global disease which especially occurs in elderly people. Its incidence varies widely between populations, with the highest incidence among Caucasians, and a South-to-North increase in Europe. As northern Europeans often have blond hair and light eyes, we wondered whether iris colour may be a predisposing factor for UM and if so, why. We compared the distribution of iris colour between Dutch UM patients and healthy Dutch controls, using data from the Rotterdam Study (RS), and reviewed the literature regarding iris colour. We describe molecular mechanisms that might explain the observed associations. When comparing a group of Dutch UM patients with controls, we observed that individuals from Caucasian ancestry with a green/hazel iris colour (Odds Ratio (OR) = 3.64, 95% Confidence Interval (CI) 2.57-5.14) and individuals with a blue/grey iris colour (OR = 1.38, 95% CI 1.04-1.82) had a significantly higher crude risk of UM than those with brown eyes. According to the literature, this may be due to a difference in the function of pheomelanin (associated with a light iris colour) and eumelanin (associated with a brown iris colour). The combination of light-induced stress and aging may affect pheomelanin-carrying melanocytes in a different way than eumelanin-carrying melanocytes, increasing the risk of developing a malignancy.

Uveal melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. UMs are usually initiated by a mutation in GNAQ or GNA11, unlike cutaneous melanomas, which usually harbour a BRAF or NRAS mutation. The annual incidence in Europe and the USA is ~6 per million population per year. Risk factors include fair skin, light-coloured eyes, congenital ocular melanocytosis, ocular melanocytoma and the BAP1-tumour predisposition syndrome. Ocular treatment aims at preserving the eye and useful vision and, if possible, preventing metastases. Enucleation has largely been superseded by various forms of radiotherapy, phototherapy and local tumour resection, often administered in combination. Ocular outcomes are best with small tumours not extending close to the optic disc and/or fovea. Almost 50% of patients develop metastatic disease, which usually involves the liver, and is usually fatal within 1 year. Although UM metastases are less responsive than cutaneous melanoma to chemotherapy or immune checkpoint inhibitors, encouraging results have been reported with partial hepatectomy for solitary metastases, with percutaneous hepatic perfusion with melphalan or with tebentafusp. Better insight into tumour immunology and metabolism may lead to new treatments.

Quantitative bias analysis for study and grant planning

PURPOSE

Epidemiologists often think about the balance between study error and cost-efficiency in terms of study design and strategies to reduce random error. We less often consider cost-efficiencies in terms of dealing with systematic errors that arise within a study, such as in deciding how to measure study variables and misclassification implications.

METHODS

Given the information used to inform a study size calculation, the expected study data can be simulated during study planning, and the impact of anticipated biases can be estimated using quantitative bias analysis. This would allow investigators and stakeholders to identify areas where better data collection through more valid instruments is critical and where additional investment will not yield strong validity benefits. This could promote better use of study resources and help increase investigators' chances of funding by demonstrating they have thought through biases and have a plan for mitigating the impact.

RESULTS

We demonstrate how this would work with a practical example using the relationship between smoking during pregnancy as measured on birth certificates and incident breast cancer.

CONCLUSIONS

We show that although exposure sensitivity would likely be poor, spending more money to get a better smoking measure is unlikely to yield more valid estimates.

Nonparticipation Selection Bias in the MOBI-Kids Study

Supplemental Digital Content is available in the text.

Background:

MOBI-Kids is a 14-country case–control study designed to investigate the potential effects of electromagnetic field exposure from mobile telecommunications devices on brain tumor risk in children and young adults conducted from 2010 to 2016. This work describes differences in cellular telephone use and personal characteristics among interviewed participants and refusers responding to a brief nonrespondent questionnaire. It also assesses the potential impact of nonparticipation selection bias on study findings.

Methods:

We compared nonrespondent questionnaires completed by 77 cases and 498 control refusers with responses from 683 interviewed cases and 1501 controls (suspected appendicitis patients) in six countries (France, Germany, Israel, Italy, Japan, and Spain). We derived selection bias factors and estimated inverse probability of selection weights for use in analysis of MOBI-Kids data.

Results:

The prevalence of ever-regular use was somewhat higher among interviewed participants than nonrespondent questionnaire respondents 10–14 years of age (68% vs. 62% controls, 63% vs. 48% cases); in those 20–24 years, the prevalence was ≥97%. Interviewed controls and cases in the 15- to 19- and 20- to 24-year-old age groups were more likely to have a time since start of use of 5+ years. Selection bias factors generally indicated a small underestimation in cellular telephone odds ratios (ORs) ranging from 0.96 to 0.97 for ever-regular use and 0.92 to 0.94 for time since start of use (5+ years), but varied in alternative hypothetical scenarios considered.

Conclusions:

Although limited by small numbers of nonrespondent questionnaire respondents, findings generally indicated a small underestimation in cellular telephone ORs due to selective nonparticipation.

Probabilistic Multiple-Bias Modeling Applied to the Canadian Data From the Interphone Study of Mobile Phone Use and Risk of Glioma, Meningioma, Acoustic Neuroma, and Parotid Gland Tumors

We undertook a re-analysis of the Canadian data from the 13-country case-control Interphone Study (2001-2004), in which researchers evaluated the associations of mobile phone use with the risks of brain, acoustic neuroma, and parotid gland tumors. In the main publication of the multinational Interphone Study, investigators concluded that biases and errors prevented a causal interpretation. We applied a probabilistic multiple-bias model to address possible biases simultaneously, using validation data from billing records and nonparticipant questionnaires as information on recall error and selective participation. In our modeling, we sought to adjust for these sources of uncertainty and to facilitate interpretation. For glioma, when comparing those in the highest quartile of use (>558 lifetime hours) to those who were not regular users, the odds ratio was 2.0 (95% confidence interval: 1.2, 3.4). After adjustment for selection and recall biases, the odds ratio was 2.2 (95% limits: 1.3, 4.1). There was little evidence of an increase in the risk of meningioma, acoustic neuroma, or parotid gland tumors in relation to mobile phone use. Adjustments for selection and recall biases did not materially affect interpretation in our results from Canadian data.

Innovative research methods for studying treatments for rare diseases: methodological review

OBJECTIVE

To examine methods for generating evidence on health outcomes in patients with rare diseases.

DESIGN

Methodological review of existing literature.

SETTING

PubMed, Embase, and Academic Search Premier searched for articles describing innovative approaches to randomized trial design and analysis methods and methods for conducting observational research in patients with rare diseases.

MAIN OUTCOME MEASURES

We assessed information related to the proposed methods, the specific rare disease being studied, and outcomes from the application of the methods. We summarize methods with respect to their advantages in studying health outcomes in rare diseases and provide examples of their application.

RESULTS

We identified 46 articles that proposed or described methods for studying patient health outcomes in rare diseases. Articles covered a wide range of rare diseases and most (72%) were published in 2008 or later. We identified 16 research strategies for studying rare disease. Innovative clinical trial methods minimize sample size requirements (n=4) and maximize the proportion of patients who receive active treatment (n=2), strategies crucial to studying small populations of patients with limited treatment choices. No studies describing unique methods for conducting observational studies in patients with rare diseases were identified.

CONCLUSIONS

Though numerous studies apply unique clinical trial designs and considerations to assess patient health outcomes in rare diseases, less attention has been paid to innovative methods for studying rare diseases using observational data.

Studying the impact of early life exposures to pesticides on the risk of testicular germ cell tumors during adulthood (TESTIS project): study protocol

BACKGROUND

The incidence of testicular germ cell tumors (TGCT), the most common cancer in men aged 15 to 45 years, has doubled over the last 30 years in developed countries. Reasons remain unclear but a role of environmental factors, especially during critical periods of development, is strongly suspected. Reliable data on environmental exposure during this critical time period are sparse. Little is known on whether it could be a combined effect of early and later-life exposures.

METHODS/DESIGN

Our research aims to study the association between TGCT risk and pesticide exposures (domestic, occupational and environmental) during critical time periods of development and combined early and later-life exposures. The study design, developed during a 2-year pilot study, is a multicenter case-control study of 500 cases (ascertained through histology) and 1000 fertile/fecund controls recruited through 21 French 'Centres d'Etude et de Conservation des Œufs et de Sperme humain' (CECOS). Trained professional interviewers interview the subjects and their mothers by phone. Using a geographic information system developed and tested for application in this study design, environmental pesticides exposure assessment is based on life-time residential history. Occupational pesticides exposures are assessed by an industrial hygienist based on parents' occupations and tasks. Exposures during the prenatal period, early childhood and puberty are focused. A blood sample is collected from each participant to assess genetic polymorphisms known to be associated with TGCT risk, as well as to explore gene-environment interactions.

DISCUSSION

The results of our study will contribute to better understanding the causes of TGCT and the rapid increase of its incidence. We explore the effect of combined early and later-life pesticides exposure from multiple sources, as well as potential gene-environment interactions that have until now been rarely studied for TGCT. Our design allows future pooled studies and the bio-bank allows additional genetic or toxicological analyses.

Having children, social characteristics, smoking and the risk of uveal melanoma: a case-control study

PURPOSE

We analyzed data from the Risk Factors for Uveal Melanoma (RIFA) study to evaluate possible associations between uveal melanoma risk and having children, socioeconomic level and smoking.

METHODS

The RIFA study was a German case-control study conducted from September 2002 to March 2005. The study population consisted of 455 incident uveal melanoma patients (20-74 years of age) and 827 matched (age, sex, region of residence) population controls. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression.

RESULTS

Women with children showed an increased OR (1.59, 95% CI 0.95-2.66) for uveal melanoma development compared to women without children. We estimated decreased ORs for subjects with higher socioeconomic level compared to the lowest status (upper secondary school leaving certificate: OR 0.68, 95% CI 0.49-0.94; higher education: OR 0.60, 95% CI 0.38-0.96). Ever smokers showed an OR of 1.19 (95% CI 0.92-1.55) compared to never smokers.

CONCLUSION

The observed association between lower socioeconomic level and increased odds for uveal melanoma possibly represents a higher occupational uveal melanoma risk for occupational categories that are usually associated with lower socioeconomic status. Concerning having children and uveal melanoma development, we hypothesize that the observed association is mediated through alpha-melanocyte-stimulating hormone, a hormone that increases during pregnancy and is linked to pigmentation alterations in pregnant women.

Ocular melanoma: an overview of the current status

Ocular melanoma is the second most common type of melanoma after cutaneous and the most common primary intraocular malignant tumor in adults. Large majority of ocular melanomas originate from uvea, while conjunctival melanomas are far less frequent. Incidence of uveal melanoma has remained stable over last three decades. Diagnosis is in most cases established by clinical examination with great accuracy. Local treatment of uveal melanoma has improved, with increased use of conservative methods and preservation of the eye, but survival rates have remained unchanged. Recent advances in cytogenetics and genetics enhanced prognostication and enabled to determine tumors with high metastatic potential. However, due to lack of effective systemic therapy, prognosis of patients with metastasis remains poor and metastatic disease remains the leading cause of death among patients with uveal melanoma. Conjunctival melanoma is rare, but its incidence is increasing. It mostly occurs among white adults. In majority of cases it originates from preceding primary acquired melanosis. Current standard treatment for conjunctival melanoma is wide local excision with adjuvant therapy, including brachytherapy, cryotherapy and topical application of chemotherapeutic agent. Rarity of this tumor limits conduction of controlled trials to define the best treatment modality. As well as for uveal melanoma, prognosis of patients with metastasis is poor because there is no effective systemic therapy. Better understanding of underlying genetic and molecular abnormalities implicated in development and progression of ocular melanomas provides a great opportunity for development of targeted therapy, which will hopefully improve prognosis of patients with metastatic disease.

A case-control study: occupational cooking and the risk of uveal melanoma

Background

A European-wide population based case-control study (European rare cancer study) undertaken in nine European countries examined risk factors for uveal melanoma. They found a positive association between cooks and the risk of uveal melanoma. In our study we examine whether cooks or people who worked in cook related jobs have an increased uveal melanoma risk.

Methods

We conducted a case-control study during 2002 and 2005. Overall, 1653 eligible subjects (age range: 20-74 years, living in Germany) participated. Interviews were conducted with 459 incident uveal melanoma cases, 827 population controls, 180 ophthalmologist controls and 187 sibling controls. Data on occupational exposure were obtained from a self-administered postal questionnaire and a computer-assisted telephone interview. We used conditional logistic regression to estimate odds ratios adjusting for the matching factors.

Results

Overall, we did not observe an increased risk of uveal melanoma among people who worked as cooks or who worked in cook related jobs. When we restricted the source population of our study to the population of the Federal State of Northrhine-Westphalia, we observed an increased risk among subjects who were categorized as cooks in the cases-control analysis.

Conclusion

Our results are in conflict with former results of the European rare cancer study. Considering the rarity of the disease laboratory in vitro studies of human uveal melanoma cell lines should be done to analyze potential exposure risk factors like radiation from microwaves, strong light from incandescent ovens, or infrared radiation.