Increased incidence of choroidal malignant melanoma occurring in a single population of chemical workers

Clustering of uveal melanoma: County wide analysis within Ohio

PURPOSE

To determine if a greater than expected number of cases (clustering) of uveal melanoma occurred within Ohio for any specific region or time period as compared to others.

DESIGN

Analysis of population database.

METHODS

Ohio Cancer Incidence Surveillance System (OCISS) database (2000-2019) was accessed for the diagnosis of uveal melanoma using the International Classification of Disease for Oncology codes: C69.3 (choroid), C69.4 (ciliary body and iris). Counties within Ohio were grouped by geographic regions (7) and socioeconomic variables. Age- and race-standardized incidence ratios (SIR) were calculated to determine temporal or geographic clustering.

RESULTS

Over the twenty-year period, the total number of uveal melanoma cases reported within Ohio were 1,617 with the overall age-adjusted annual incidence of 6.72 cases per million population (95% CI 6.30-7.16). There was an increase in the incidence of uveal melanoma over 20 years (p<0.001) across seven geographic regions, but no significant difference in incidence rates between the regions. There was no difference in incidence based on county classification by age composition (p = 0.14) or education level (p = 0.11). Counties with a low median household income (p<0.001), those classified as urban (p = 0.004), and those with a greater minority population (p = 0.004) had lower incidence. Less populated counties had a higher incidence of uveal melanoma (p<0.001).

CONCLUSIONS

There is no evidence of geographic or temporal clustering of uveal melanoma within Ohio from 2000 to 2019.

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.

The occurrence and proposed significance of Schnabel cavernous degeneration in uveal melanoma

IMPORTANCE

Schnabel cavernous degeneration (SCD) has been observed in eyes with uveal melanoma (UM), but, to our knowledge, a definitive study establishing the association between SCD and UM has not been conducted.

OBJECTIVE

To explore an association between SCD and UM.

DESIGN, SETTING, AND PARTICIPANTS

A historical cohort analysis was performed using histologic slides and related clinical records of cases from the Collaborative Ocular Melanoma Study and Eye Pathology Laboratory at the University of Wisconsin, including 1985 UM eyes, 517 eye bank eyes, and 155 enucleated glaucomatous eyes.

MAIN OUTCOMES AND MEASURES

The prevalence of SCD was calculated and compared between each group; subgroup analysis was also conducted of eyes with and without SCD for the prevalence of glaucoma.

RESULTS

Schnabel cavernous degeneration was seen in 17 (0.9%) UM eyes, 9 (1.7%) eye bank eyes, and 2 (1.3%) enucleated glaucomatous eyes. No difference was detected between the prevalence of SCD in UM eyes and eye bank eyes (odds ratio [OR], 0.49; 95% CI, 0.22-1.10) or enucleated glaucomatous eyes (OR, 0.66; 95% CI, 0.15-2.89). Subgroup analysis, performed on 421 UM eyes, provided sufficient clinical information to definitively establish the presence or absence of glaucoma. Of the 95 (22.6%) eyes with glaucoma, 11 (11.6%) revealed histopathologic evidence of SCD. Compared with enucleated end-stage glaucoma eyes, this represents a 10-fold increase in SCD in UM eyes with glaucoma (OR, 10.10; 95% CI, 2.17-46.26). The prevalence of glaucoma in UM eyes with SCD, however, was respectively 7- and 15-fold higher than the prevalence of glaucoma in SCD-negative UM eyes (OR, 6.98; 95% CI, 2.51-19.43) and SCD-positive eye bank eyes (OR, 14.67; 95% CI, 1.46-146.97).

CONCLUSIONS AND RELEVANCE

Although an association between SCD and UM was not confirmed, subgroup analysis did reveal an increased incidence of SCD in eyes with both UM and glaucoma. This suggests that the occurrence of glaucoma may increase the risk of SCD in eyes with UM.

Population-based incidence of uveal melanoma in various races and ethnic groups

PURPOSE

To investigate racial/ethnic differences in the development of uveal malignant melanoma in a large population-based study.

DESIGN

Observational cross-sectional study.

METHODS

With the 1992 to 2000 data that was provided by the National Cancer Institute's Surveillance, Epidemiology, and End Results Program, we calculated age-adjusted incidence rates of uveal melanoma in various racial/ethnic groups (black, Asian and Pacific Islander, Hispanic, and non-Hispanic white). In addition, we calculated the standard incidence ratio (risk ratio) and 95% confidence interval to describe the differences within these racial/ethnic groups.

RESULTS

From 1992 to 2000, there were a total of 1352 uveal melanomas that were diagnosed in 11 Surveillance, Epidemiology, and End Results registries with known racial/ethnic groups. The annual age-adjusted incidence (per million population) of uveal melanoma was 0.31 (black), 0.38 (Asian), 1.67 (Hispanic), and 6.02 (non-Hispanic white). The difference in the incidence of uveal melanoma between each racial/ethnic group was highly statistically significant, with the exception of the black versus the Asian population in which there was no statistically significant difference.

CONCLUSION

The relative risk of uveal melanoma was 1.2 for Asian and Pacific Islander patients, 5.4 for Hispanic patients, and 19.2 for non-Hispanic white patients as compared with the black patients. If the non-Hispanic white population and the Hispanic population were combined, then the overall white:black ratio was 18:1.

Case-control study on uveal melanoma (RIFA): rational and design

Background

Although a rare disease, uveal melanoma is the most common primary intraocular malignancy in adults, with an incidence rate of up to 1.0 per 100,000 persons per year in Europe. Only a few consistent risk factors have been identified for this disease. We present the study design of an ongoing incident case-control study on uveal melanoma (acronym: RIFA study) that focuses on radiofrequency radiation as transmitted by radio sets and wireless telephones, occupational risk factors, phenotypical characteristics, and UV radiation.

Methods/Design

We conduct a case-control study to identify the role of different exposures in the development of uveal melanoma. The cases of uveal melanoma were identified at the Division of Ophthalmology, University of Essen, a referral centre for tumours of the eye. We recruit three control groups: population controls, controls sampled from those ophthalmologists who referred cases to the Division of Ophthalmology, University of Duisburg-Essen, and sibling controls. For each case the controls are matched on sex and age (five year groups), except for sibling controls. The data are collected from the study participants by short self-administered questionnaire and by telephone interview. During and at the end of the field phase, the data are quality-checked.

To estimate the effect of exposures on uveal melanoma risk, we will use conditional logistic regression that accounts for the matching factors and allows to control for potential confounding.

Occupational risk in health care and research

BACKGROUND

Working in the health care and research sectors has been linked to various hazards.

METHODS

Studies published in the peer-reviewed literature that are pertinent to the exposures or diseases relevant to these fields were reviewed.

RESULTS

The most important exposures include infectious agents, formaldehyde, anesthetic agents, antineoplastic drugs, and ethylene oxide. The best-documented evidence is that of infectious risk primarily among clinical personnel. Monitoring studies of persons occupationally exposed to anesthetics clearly demonstrate behavioral effects, possible risk of reproductive problems, as well as cytogenetic effects of unknown significance. The latter two impairments are also observed among those exposed to antineoplastic drugs and ethylene oxide. Exposure to formaldehyde appears to be associated with nasopharyngeal tumors. Whereas increased risk of cancer of certain sites, particularly the brain and lymphohematopoietic system, is found among research and health care personnel, no specific exposure has been linked to these neoplasms.

CONCLUSIONS

Although some results are inconsistent, continued environmental and biological monitoring will allow better assessment of exposures and of implemented protection measures.

The possible role of radiofrequency radiation in the development of uveal melanoma

There are few epidemiologic studies dealing with electromagnetic radiation and uveal melanoma. The majority of these studies are exploratory and are based on job and industry titles only. We conducted a hospital-based and population-based case-control study of uveal melanoma and occupational exposures to different sources of electromagnetic radiation, including radiofrequency radiation. We then pooled these results. We interviewed a total of 118 female and male cases with uveal melanoma and 475 controls matching on sex, age, and study regions. Exposure to radiofrequency-transmitting devices was rated as (a) no radiofrequency radiation exposure, (b) possible exposure to mobile phones, or (c) probable/certain exposure to mobile phones. Exposures were rated independently by two of the authors who did not know case or control status. We used conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). We found an elevated risk for exposure to radiofrequency-transmitting devices (exposure to radio sets, OR = 3.0, 95% CI = 1.4-6.3; probable/certain exposure to mobile phones, OR = 4.2, 95% CI = 1.2-14.5). Other sources of electromagnetic radiation such as high-voltage lines, electrical machines, complex electrical environments, visual display terminals, or radar units were not associated with uveal melanoma. This is the first study describing an association between radiofrequency radiation exposure and uveal melanoma. Several methodologic limitations prevent our results from providing clear evidence on the hypothesized association.

Trends in eye cancer mortality among adults in the USA and England and Wales

Trends in eye cancer mortality are presented for the USA and England and Wales during the period 1955-89. Mortality rates have fallen by 58% in the USA during this period. The fall in mortality is paralleled by an equal fall in incidence rates in the USA. In England and Wales, mortality rates and incidence rates have remained relatively constant during the last three decades. The explanation for these differences between the USA and England and Wales is unknown.

Uptake of 7,12-dimethylbenz(a)anthracene and benzo(a)pyrene in melanin-containing tissues

It is widely accepted that UV exposure is the main etiological factor for malignant melanoma. Epidemiologic studies, however, have indicated that also chemical carcinogens may be a risk factor for the disease. Polycyclic aromatic hydrocarbons such as 7,12-dimethylbenz(a)anthracene and benzo(a)pyrene represent an important class of carcinogenic chemicals. It is known that 7,12-dimethylbenz(a)anthracene can induce melanotic tumours in various animal species, and human melanocytes in culture have been found to be capable of metabolizing benzo(a)pyrene to its proximate carcinogen benzo(a)pyrene-7,8-diol. In the present study the disposition of 14C- and 3H-7,12-dimethylbenz(a)anthracene and 14C-benzo(a)pyrene was studied in pigmented and albino mice and Syrian golden hamsters by whole-body autoradiography. The results showed pronounced retention of label in the melanin-containing structures of the eyes and the hair follicles in the pigmented animals. The labelling of the corresponding structures in the albino animals was low. Additional experiments showed that 7,12-dimethylbenz(a)anthracene and benzo(a)pyrene as well as some of their metabolites are bound to melanin in vitro. The specific localization of the polycyclic aromatic hydrocarbons in pigmented tissues due to melanin affinity, combined with bioactivating capacity of melanocytes, suggest that these substances may play a role in the induction of malignant melanoma.

An epidemiological study of posterior uveal melanoma in Israel, 1961-1989

Trends in the incidence rate of uveal melanoma in Israel during the period 1961-1989 among Jews of various geographical origins and among non-Jews were examined, and found to be stable over time. Based on data of the Israel Cancer Registry, 515 cases were included in the final study population after an independent case-finding ascertainment survey. The average annual incidence rate per million for all Jews was 5.7 for both males and females; the rates for non-Jews were: males 1.6, females 1.3. Incidence rates within the Jewish sub-populations show significant differences. The highest rates by sub-population were for Jews born in Europe or America (7.5 for males and for females), followed by Jews born in Israel (males 6.8, females 6.7); and lowest in Jews born in Africa (males 2.1, females 2.3) and Asia (males 1.6, females 2.8). Jews born in Israel had rates lower than Jews born in Europe and America during the 1960s, but in the 1980s the situation was reversed. Results suggest that rate differences between population groups and over time stem from constitutional factors or from the direct or indirect effect of sunlight radiation, whether early in life or from cumulative exposure.

Ocular melanoma in childhood

A case of primary ocular melanoma of the iris in a 10 year old girl is reported. Primary melanoma of the eye is exceedingly rare in childhood. The incidence and risk factors for ocular melanoma are discussed and possible reasons why this tumour is so uncommon in younger age groups are considered.

Interaction between chemicals and melanin

Various drugs and other chemicals, such as organic amines, metals, polycyclic aromatic hydrocarbons, etc., are bound to melanin and retained in pigmented tissues for long periods. The physiological significance of the binding is not evident, but it has been suggested that the melanin protects the pigmented cells and adjacent tissues by adsorbing potentially harmful substances, which then are slowly released in nontoxic concentrations. Long-term exposure, on the other hand, may build up high levels of noxious chemicals, stored on the melanin, which ultimately may cause degeneration in the melanin-containing cells, and secondary lesions in surrounding tissues. In the eye, e.g., and in the inner ear, the pigmented cells are located close to the receptor cells, and melanin binding may be an important factor in the development of some ocular and inner ear lesions. In the brain, neuromelanin is present in nerve cells in the extrapyramidal system, and the melanin affinity of certain neurotoxic agents may be involved in the development of parkinsonism, and possibly tardive dyskinesia. In recent years, various carcinogenic compounds have been found to accumulate selectively in the pigment cells of experimental animals, and there are many indications of a connection between the melanin affinity of these agents and the induction of malignant melanoma.

Occupation and risk of uveal melanoma. An exploratory study

BACKGROUND

Little is known about the cause of uveal melanoma, the most common primary intraocular malignant lesion in adults. This population-based case-control study evaluated occupational exposures.

METHODS

One hundred ninety-seven newly diagnosed cases of uveal melanoma participated. Approximately two control subjects matched for age, sex, and telephone exchange area were selected for each case by random-digit dialing. Data were collected by a structured telephone interview. Two systems of occupational coding were used: an occupation-exposure linkage system and the Bureau of Census data. Conditional logistic regression for matched studies was used to examine various occupational exposures while controlling for previously reported potential confounders and for family income. The occupation-exposure matrix was used to define clusters of cases exposed to a particular chemical group from various occupations.

RESULTS

Odds ratios were elevated for agriculture and farming work for both industry and occupation; this was consistent across both classification systems. Elevated odds ratios also were found for occupations involving machine operations, fabrication, assembling, equipment cleaning, and exposure to metal industries. Exposure to alkylating agents and phenols was associated with a lower risk compared with all other exposures. Several self-reported exposures also were studied. Exposures associated with elevated odds ratios were inks, insecticides, gases, radioactive substances, polybromated biphenyls, and chemical solvents.

CONCLUSIONS

This exploratory study suggests various occupational associations for uveal melanoma and areas for future research.

Other cancers in uveal melanoma patients and their families

To determine associations with other cancers, 400 consecutive uveal melanoma patients examined at Wills Eye Hospital between 1984 and 1985 were surveyed regarding personal and family history of cancer. Responses were received from 333 (83%). Sixty patients reported 43 nonbasal cell second primary cancers, which were confirmed pathologically or by physician records. The overall prevalence of nonbasal cell cancers diagnosed in uveal melanoma patients by December 1985 was over two times greater than the expected prevalence, based on the Connecticut Tumor Registry data for an age- and sex-matched population. Gynecologic cancers tended to be more common in uveal melanoma female patients than in the comparison population. Although the observed prevalence of cutaneous melanoma was not significantly greater than expected, three cases with both primary cutaneous and uveal melanoma were reported. Family histories of cutaneous melanoma were confirmed in 14 patients, and uveal melanoma in two patients. Data suggested that the overall cancer prevalence in uveal melanoma patients may be increased, that hormonal factors may play a role in the genesis of this malignancy, and that there may be a link between cutaneous and uveal melanoma.

Familial uveal melanoma

The cause of uveal melanoma is unknown. In a few cases, however, factors are found in association with the disease which may play some part in the aetiology. One such factor is inheritance. Twelve families have been reported with adequate documentation during the last century in which two or more members have had uveal melanomas. At least some of these may be the result of an inherited disorder. On available data inheritance is most likely autosomal dominant with partial expressivity or incomplete penetrance. This report describes two more families each of which have two members with uveal melanomas.

Epidemiologic aspects of uveal melanoma

Although the underlying cause or causes of uveal melanoma have yet to be elucidated, important insights may be gained by examining the epidemiologic features of the disease. Uveal melanoma is an uncommon cancer with an incidence of only six cases per million population per year. It is most often diagnosed in the sixth decade and is somewhat more common in males. Apart from sporadic reports of family clusters, uveal melanoma is not considered an inherited disease. Whether some environmental exposure triggers the development of uveal melanoma remains an open question. Sunlight has been proposed as an environmental risk factor because sunlight is known to cause melanoma of the skin and both diseases are rare in nonwhite races. Unlike cutaneous melanoma, however, rates have not been increasing over time and do not vary by latitude. This paper evaluates the available evidence for sunlight and other potential risk factors for uveal melanoma, highlighting areas requiring further research.

Occupation and risk of cutaneous melanoma

Occupational mortality from cutaneous malignant melanoma was evaluated for deaths occurring in British Columbia from 1950-1978 by using age standardised proportional mortality ratios (PMR). For males, significantly elevated PMRs for melanoma were seen in managers and owners, accountants, architects, chemical engineers, and gardeners and nursery workers. Female school teachers were also at elevated risk of death from cutaneous melanoma.

Incidence of choroidal malignant melanoma in Finland in the years 1973-1980

Recent reports concerning the incidence of choroidal and ciliary body melanomas have raised a suspicion of an increase of this malignancy in the developed countries. The rapid rise in the incidence of melanoma of the skin is well known. This study covers the incidence of choroidal and ciliary body melanomas in Finland over the years 1973-1980. A total of 382 cases of intraocular malignant tumours were reported to the Finnish Cancer Registry. 285 choroidal and ciliary body melanomas were found. The age-specific incidences showed a steep rise from the age of 30 to the age of 70. The peak incidence was in the age-group 70 and over. There was only one case, a girl 12 of age, in the age-group 15 years and younger. The age adjusted incidences showed no significant increase during the study period. The age-specific incidence showed no significant difference compared to a previous study. Sex, laterality or latitude were not found to be risk factors.

Cancer prevention: assessing causes, exposures, and recent trends in mortality for U.S. males, 1968-1978

This paper addresses some enduring issues concerning prevention of environmental and occupational cancer. The first part reviews methodological problems of estimating cancer risks and outlines some research priorities. The second part documents countervailing trends in chemical production during the past two decades, noting the doubling of some synthetic organic human carcinogens and the leveling off of some heavy metal carcinogens. The final section details recent increases in site-specific causes of cancer mortality for men old enough to have developed workplace cancers (ages 35 to 84), considering those cancers that have been linked with exposures to toxic chemicals and to cigarette smoking. This paper points out that Doll and Peto's (1981) analysis of U.S. cancer trends does not indicate some important increases in older males; they conclude that apart from cigarette smoking, there is no generalized increase in cancer for persons up to age 64. In fact, there has been a sharp reduction in cancer mortality for those under age 45. This reduction more than offsets increases in some cancers for those ages 45 to 65. Men ages 55 to 84 have experienced major increases in mortality for certain cancers plausibly associated with occupational exposures, including cancers of the brain, lung, and multiple myeloma. These older age groups have potentially sustained longer workplace exposures to carcinogens, some of which have 25-year or greater latencies. Changes in infectious diseases, workplace exposures, diagnostic trends, environment, and nutrition require further study.

An apparent small cluster of choroidal melanoma cases

Three choroidal melanomas were detected in a 2.5-year period in a small community of 3,592 persons. This small cluster represented an incidence about 20 times that expected (P = .0006). The community has an isolated water supply and very little industry. We determined the incidence of cancer in this and two adjacent communities and found no other unexpectedly high incidence. The three patients had no common exposures. Analyses of air and water from the involved community by mass spectroscopy, chromatography, and Ames (mutagenicity) tests were noncontributory. Nine of 60 mice given community water after weaning developed lens opacities eight to 16 months later; electron microscopy showed an abnormal monolayer of cells on the outer surface of the anterior lens capsule. The genesis of this monolayer was not clear. None of the 30 controls showed such lesions.

Immunology of chorioretinal disorders

Because of its uniqueness, the eye has long been a favored site for immunological study. It is a highly active tissue immunologically, with virtually all types of immune reactions present. This article reviews the ocular immune response, chorioretinal diseases with immunologic features, and immunology of ocular tumors. Immunologic data is discussed as it relates to the pathogenesis, clinical features, and therapy of chorioretinal disease.