Cancers in Australia attributable to exposure to solar ultraviolet radiation and prevented by regular sunscreen use

Objectives: To estimate the proportion and numbers of cancers occurring in Australia attributable to solar ultraviolet radiation (UVR) and the proportion and numbers prevented by regular sun protection factor (SPF) 15+ sunscreen use. Methods: We estimated the population attributable fraction (PAF) and numbers of melanomas and keratinocyte cancers (i.e. basal cell carcinomas and squamous cell carcinomas) due to exposure to ambient UVR resulting from residing in Australia versus residing in the UK (for melanoma) or Scandinavia (for keratinocyte cancers). We also estimated the prevented fraction (PF): the proportion of cancers that would have occurred but were likely prevented by regular sunscreen use. Results: An estimated 7,220 melanomas (PAF 63%) and essentially all keratinocyte cancers occurring in Australia were attributable to high ambient UVR levels in Australia. We estimated that regular sunscreen use prevented around 14,190 (PF 9.3%) and 1,730 (PF 14%) people from developing SCC and melanoma, respectively. Conclusions: Although our approach was conservative, a high proportion of skin cancers in Australia are attributable to high ambient levels of UVR. Prevailing levels of sunscreen use probably reduced skin cancer incidence by 10–15%. Implications: Most skin cancers are preventable. Sunscreen should be a component of a comprehensive sun protection strategy.     

Occupational skin cancers

Skin cancer due to occupation is more common than is generally recognized, although it is difficult to obtain an accurate estimate of its prevalence. Over the past two centuries, occupational skin cancers have particularly been due to industrial exposure of men (it seems more so than women) to chemical carcinogens such as polycyclic hydrocarbons (e.g. from coal tar products) or to arsenic. Industrial processes have improved in most Western countries to limit this type of exposure, but those with outdoor occupations are still exposed to solar ultraviolet irradiation without this being widely recognized as an industrial hazard. Ionizing radiation such as X-rays can also cause skin cancer. Occupational skin cancers often resemble skin tumours found in non-occupational subjects, e.g. basal cell carcinoma, squamous cell carcinoma and malignant melanoma, but some pre-malignant lesions can be more specific and point to an occupational origin, e.g. tar keratoses or arsenical keratoses. An uncommon but well-recognized cause of occupational skin cancer is that which results from scar formation following an industrial burn. In the future it will be necessary to focus on preventative measures, e.g. for outdoor workers, the need to cover up in the sun and use sun protective creams and a campaign for earlier recognition of skin cancers, which are usually curable if treated in their early stages.     

Occupational exposure to ionizing and non-ionizing radiation and risk of glioma

BACKGROUND: Although the aetiology of glioma is poorly understood, the higher incidence in males has long suggested an occupational cause. AIM: To investigate possible associations between occupational exposure to ionizing, ultraviolet (UV), radiofrequency (RF) and extremely low frequency (ELF) radiation and adult glioma risk. METHODS: Case-control study using histologically confirmed cases of glioma first diagnosed between 1987 and 1991 in Melbourne, Australia, matched by age, sex and postcode of residence. A detailed occupational history was obtained for each subject. Exposure to radiation was assessed using a Finnish job exposure matrix (FINJEM) for all the radiation types as well as self-reports and expert hygienist review for RF and ionizing radiation. For ELF and UV, gender-specific FINJEM analysis was performed. RESULTS: The study population consisted of 416 cases of glioma and 422 controls. The risk estimates given by FINJEM for ELF, RF and ionizing radiation were close to or below unity. Gender-specific analysis for UV showed odds ratios of 1.60 [95% confidence interval (CI) 0.95-2.69] and 0.54 (95% CI 0.27-1.07) for the highest exposed group of men and women, respectively (corresponding P value for trend was 0.03 and 0.04). CONCLUSIONS: We did not find evidence of an association between glioma and occupational exposure to ELF, RF and ionizing radiation. UV radiation was associated with increased glioma risk for men but this result could have been confounded by other predominantly male occupational and lifestyle exposures associated with high UV. Further investigation of UV radiation and glioma risk is suggested.     

Perceptual strategies to improve skin cancer discriminations in naive observers

The aim of these experiments was to assess the effect of an educational brochure on the ability of naive observers to discriminate skin cancers from benign lesions, and to investigate possible new strategies to assist observers in performing this task. A two-alternative forced choice paradigm was used to investigate the ability of observers to correctly identify different types of benign and malignant lesions before and after exposure to an educational brochure. The method of pair comparisons was used to assess the ability of observers to discriminate between benign and malignant lesions under different instruction conditions. Subjects were undergraduate students from Sydney University. An educational brochure did not facilitate the ability to correctly identify malignant lesions, and appeared to result in deterioration of performance in the identification of benign lesions. Similarly, observers were unable to discriminate between benign and malignant lesions on the basis of how dangerous they looked. However, judgements of lesions in terms of perceived distinctiveness resulted in relatively accurate discriminations between benign and malignant lesions. These data suggest current skin cancer detection strategies may be ineffective in improving the ability to visually identify benign and malignant lesions. Discriminating between lesions in terms of how distinctive they appear may form the basis of a new and effective strategy for the detection of skin cancer.     

Occupational skin infections

A number of skin infections may complicate different occupations depending on the working environment and level of exposure to a particular agent. These in turn may affect the productivity of an individual worker and ultimately the company as a whole. This review aims to highlight some common and important skin infections that may be acquired at work. Epidemiology, clinical features, diagnosis, treatment and prevention will be covered.     

Mortality and cancer incidence in Ontario glass fiber workers

BACKGROUND: In a previous cohort study of glass fiber manufacturing, we found a significant increase in lung cancer. This study extends the follow-up period. METHODS: We conducted a historical prospective study of 2557 men employed in producing glass wool. We obtained work histories, causes and dates of death, and date and site of cancer diagnoses. We computed standardized mortality and incidence ratios (SMR, SIR). RESULTS: The overall SMR for lung cancer was 163 (95% CI = 118-221). The SMR did not vary consistently by duration of employment and time since first employment. However, plant workers with >20 years' employment and >40 years since first exposure had an SMR for lung cancer of 282 (95% CI = 113-582). The SMR dropped with later date of first exposure, but the trend was non-significant. There was an unexpected overall increase in kidney cancer incidence. DISCUSSION: The increase in lung cancer is greater than in other cohorts of glass fiber workers. Since exposure data are lacking from the early years of the plant, we cannot state if the excess was due to glass fibers, other work exposures or other reasons.     

Increased cancer risk among surgeons in an orthopaedic hospital

BACKGROUND: Five cancer cases over 7 years were reported in a small orthopaedic hospital where radiation protection practice was poor. AIM: To investigate whether workers subject to routine radiation dosimetric assessment in that hospital had an increased cancer risk. METHODS: One hundred and fifty-eight workers subject to routine dose assessment and 158 age-sex-matched unexposed workers were questioned about cancer occurrence. All tumours were analysed as a single diagnostic category. RESULTS: Cumulative 1976-2000 cancer incidence was 29 (9/31), 6 (8/125) and 4% (7/158) in orthopaedics, exposed other than orthopaedics, and unexposed workers, respectively. At logistic regression analysis, working as orthopaedic surgeon significantly (P<0.002) increased the risk of tumours. CONCLUSION: These findings caution against surgeons' underestimation of the potential radiation risk and insufficient promotion of safe work practices by their health care institutions.     

Occupational skin conditions in the food industry

The study presents the findings of a questionnaire survey of skin conditions in a selective sample of the UK food industry, covering companies who employ occupational physicians. The mean incidence of skin conditions in food manufacturing operations was 2103 per million employees per annum. The mean incidence in retail or catering organizations was 1414 per million employees per annum.     

Medical management of radiation injuries: current approaches

The current approach to medical management of irradiated patients begins with early diagnosis of radiation injury. Medical assessment of radiation dose is based on event history, symptomatology and laboratory results, with emphasis on time to emesis and lymphocyte depletion kinetics. Dose assessment provides a basis for early use of haematopoietic growth factors that can shorten the period of neutropaenia for patients with acute radiation syndrome. Assessments of haematopoietic, gastrointestinal and cutaneous syndromes have improved in recent years, but treatment options remain limited. Selected examples of current developments are presented.     

Neurological effects of radiofrequency radiation

BACKGROUND: The health effects of radiofrequency radiation (RFR) and the adequacy of the safety standards are a subject of debate. One source of human data is case reports regarding peripheral neurological effects of RFR, mainly noxious sensations or dysaesthesiae. AIM: To investigate health effects, neurophysiological mechanisms and safety levels for RFR. METHODS: We conducted a literature search for case reports and case series associated with mobile phone technology as well as other RFR sources using specific search terms on PubMed. RESULTS: We identified 11 original articles detailing case reports or case series and matching the search criteria. Five of the identified papers were written by at least one of the authors (B.H. or R.W.). CONCLUSIONS: Cases have arisen after exposure to much of the radiofrequency range. In some cases, symptoms are transitory but lasting in others. After very high exposures, nerves may be grossly injured. After lower exposures, which may result in dysaesthesia, ordinary nerve conduction studies find no abnormality but current perception threshold studies have found abnormalities. Only a small proportion of similarly exposed people develop symptoms. The role of modulations needs clarification. Some of these observations are not consistent with the prevailing hypothesis that all health effects of RFR arise from thermal mechanisms.     

Two cases of thyroid cancer in a small workforce

In 1994, in a large parcel depot in the north of England employing 600 staff and 24 electrical and mechanical engineers, two engineers developed papillary cell carcinoma of the thyroid in the same year. A comprehensive review of the literature revealed that ionizing radiation is the only known direct cause of this disease. There was speculation that air filter changing undertaken by the two men affected, shortly after the Chernobyl accident in 1986, may have exposed them to concentrated radioactive fallout. A radiation survey of the parcel depot was undertaken and revealed no evidence of abnormal radioactivity. A total of 27 past and present engineering staff were screened for thyroid cancer. No cases of thyroid cancer were found. Investigation of clusters of rare disease in the occupational setting is indicated mainly in order to address the concerns of the workforce. Nevertheless, investigation is warranted, especially when the aetiology of a disease is poorly understood. It would be prudent for doctors, in whatever speciality, to take an occupational history from individuals who develop thyroid cancer.     

New advances in radiation biology

Current understanding of risk associated with low-dose radiation exposure has for many years been embedded in the linear-no-threshold (LNT) approach, based on simple extrapolation from the Japanese atomic bomb survivors. Radiation biology research has supported the LNT approach although much of this has been limited to relatively high-dose studies. Recently, with new advances for studying effects of low-dose exposure in experimental models and advances in molecular and cellular biology, a range of new effects of biological responses to radiation has been observed. These include genomic instability, adaptive responses and bystander effects. Most have one feature in common in that they are observed at low doses and suggest significant non-linear responses. These new observations pose a significant challenge to our understanding of low-dose exposure and require further study to elucidate mechanisms and determine their relevance.     

Development of a porcine skin injury model and characterization of the dose-dependent response to high-dose radiation

A porcine skin model was developed to characterize the dose-dependent response to high-dose radiation. The dorsal skin of a mini pig was divided into four paraspinal sections, with 11 small irradiation fields (2 cm × 2 cm) in each section, and a single fraction of 15, 30, 50 or 75 Gy was delivered to each section using a 6 MeV electron beam. A spectrophotometer measured gross skin changes, and a biopsy for each radiation dose was performed in the 1st, 2nd, 4th, 6th and 9th weeks for histology, immunostaining with anti-CD31, and western blotting with IL-6 and TGF-β1 to determine the degree of skin damage. After a 4-week latency period, erythema and dry desquamation, moist desquamation, and ulceration appeared at 4, 6 and 9 weeks, respectively. Gross skin toxicity was more pronounced, occurred early and continued to progress with irradiation >50 Gy, whereas complete healing was observed 12 weeks after 15 Gy. Spectrophotometry showed erythema indices rapidly increased during the first 4 weeks after irradiation. The number of eosinophils began rising sharply at 4 weeks and normalized after reaching peaks at 7–8 weeks. Microvessel density showed a biphasic pattern with a transient peak at 1 week, a nadir at 4–6 weeks, and maximum recovery at 9 weeks. Increase in the levels of IL-6 and TGF-β1 was detected soon after irradiation. Most of these parameters indicated complete healing of the skin 12 weeks after 15 Gy. Our porcine skin model provides an effective platform for studying high-dose radiation-induced skin injury, in particular histologic and molecular changes, during the early latency period.     

Investigation of cancer incidence and mortality at a Scottish semiconductor manufacturing facility

BACKGROUND: We became aware of concern about cancer at a Scottish semiconductor manufacturing facility in 1998. Aim To compare cancer experience among current and former workers at the facility, with an appropriate comparison population, making use of any readily available exposure information. METHOD: We obtained personnel and employment episode information from four sources within the company. Workers were flagged for death and cancer registrations at the National Health Service Central Register in Edinburgh. We constructed standardized registration and mortality ratios (SRRs and SMRs), using Scotland as the comparison, with and without an adjustment for deprivation. RESULTS: The main mortality analysis included 4388 workers, with a mean length of follow-up of 12.5 years. Overall mortality was substantially below that expected for men, and for women was slightly below expected. Total cancer registrations were close to expected levels for men and women. Four cancers produced noteworthy findings: malignant neoplasm of the trachea, bronchus and lung in women-deprivation adjusted SRR [95% confidence interval (CI), number of cases] 273 (136-488, 11 cases); malignant neoplasm of the stomach in women-adjusted SRR 438 (90-1281, three cases); and malignant neoplasm of the female breast-adjusted SRR 134 (82-206, 20 cases). The unadjusted SMR for male brain cancer was 401 (83-1172, three cases) and there was an additional non-fatal case. CONCLUSION: These findings, particularly those relating to lung cancer, though inconclusive, point to the possibility of a work-related risk of cancer that justifies further investigation.     

Incidence by occupation and industry of work-related skin diseases in the United Kingdom, 1996-2001

BACKGROUND: Work-related skin disease is common but few cases are documented in statutory reports or disability systems. Voluntary reporting by specialist physicians provides more complete information. AIMS: To summarize incidence rates of work-related skin diseases reported by consultant dermatologists and occupational physicians, with emphasis on contact and allergic dermatitis by occupation and industry. METHODS: Cases reported in 1996-2001 to the EPIDERM and OPRA national surveillance schemes were analysed by causal agent, occupation and industry, with incidence rates calculated against appropriate denominators. RESULTS: Average annual incidence rates based on data from dermatologists were 97 per million overall, 74 for contact dermatitis and 14 for neoplasia. The corresponding rates for occupational physicians were 623 overall, 510 and 2, respectively. For infective disease, the rates for occupational physicians were 28 compared to 2 for dermatologists. Contact dermatitis was most frequently attributed to rubber chemicals, soaps and cleaners, wet work, nickel and acrylics; most cases of contact urticaria were attributed to rubber chemicals or foods and flour. The pattern of incidence rates by occupation and industry was complex, but correlated with the probable type of exposure. Rates of contact dermatitis were highest among skilled workers in the petrochemical and rubber and plastic manufacturing industries, with machine operators and technical workers in metal and automotive industries also at increased risk. High proportions of cases attributed to rubber chemicals were in nurses and technicians in the health and social services. CONCLUSIONS: These findings identify jobs and types of work where contact with causal agents is common and potentially preventable.     

Incidence of occupational skin conditions in a food manufacturing company: results of a health surveillance programme

BACKGROUND: The food industry has been associated with a high risk of work-related skin problems. Aim To examine the incidence of work-related skin conditions and the likely causative agents in a single large food company. METHOD: Analysis of a health surveillance programme, conducted over a 7 year period, in a food company with 21 000 employees working in diverse manufacturing processes. RESULTS: The mean incidence of skin conditions, taking all of the different food manufacturing operations together, was 1310 per million employees per annum. The mean incidence was greatest in the manufacturing sector whose operations involved chilled or frozen product (3180 per million employees per annum). Most of the cases reported (184/192 = 96%) were due to primary irritant dermatitis. The two commonest suspected causes of the dermatitis were contact with ingredients and hand washing. Taken together, these factors accounted for 58% of all cases. Although the wearing of gloves is often considered necessary to prevent dermatitis from exposure to ingredients and to lessen the need for hand washing, this factor itself was responsible for 9% of all cases. CONCLUSION: Analysis of a company health surveillance scheme showed the average incidence of work-related skin problems to be lower than previously reported in the food industry.     

个体紫外线暴露剂量与环境紫外线剂量的关系

目的 了解个体紫外线暴露剂量与环境紫外线剂量的关系。方法 采用紫外线个体监测仪在秋季对沈阳市小学生和大学生进行紫外线剂量的测定，同时开展环境紫外线剂量的监测。结果 学生个体暴露量的日间分布是由户外活动时间决定，与作息时间关系密切。学生日平均暴露量只占环境剂量的1％－3％。结论 小学生的紫外线暴露量和与环境剂量的比都明显高于大学生。采用不同的监测方式所测得的环境紫外线剂量差异显著。     

Colorectal cancer among Chinese restaurant waiters

To investigate whether Chinese restaurant waiters in Hong Kong had an increased risk of dying from colorectal cancer, we linked the records of deceased union members to the mortality information for the general population between 1986 and 1995. A case-control analysis among the deceased was performed with 346 deceased waiters and 306 deceased male kitchen workers. Waiters were found to have a significantly higher mortality odds ratio [(MOR) 2.29; 95% confidence interval (CI) = 1.47-3.56] of colorectal cancer when compared with the general population. The MOR (1.45; 95% CI = 0.71-2.93) was increased, but not significantly, when compared with the kitchen workers. The study suggested that waiters in Hong Kong Chinese restaurants are at a higher risk of dying from colorectal cancer. An unhealthy diet associated with their job is a possible explanation, and interventions should be initiated.     

Incidence of cancer among commercial airline pilots

OBJECTIVES—To describe the cancer pattern in a cohort of commercial pilots by follow up through the Icelandic Cancer Registry.
METHODS—This is a retrospective cohort study of 458 pilots with emphasis on subcohort working for an airline operating on international routes. A computerised file of the cohort was record linked to the Cancer Registry by making use of personal identification numbers. Expected numbers of cancer cases were calculated on the basis of number of person-years and incidences of cancer at specific sites for men provided by the Cancer Registry. Numbers of separate analyses were made according to different exposure variables.
RESULTS—The standardised incidence ratio (SIR) for all cancers was 0.97 (95% confidence interval (95% CI) 0.62 to 1.46) in the total cohort and 1.16 (95% CI 0.70 to 1.81) among those operating on international routes. The SIR for malignant melanoma of the skin was 10.20, 95% CI 3.29 to 23.81 in the total cohort and 15.63, 95% CI 5.04 to 36.46 in the restricted cohort. Analyses according to number of block-hours and radiation dose showed that malignant melanomas were found in the subgroups with highest exposure estimates, the SIRs were 13.04 and 28.57 respectively. The SIR was 25.00 for malignant melanoma among those who had been flying over five time zones.
CONCLUSIONS—The study shows a high occurrence of malignant melanoma among pilots. It is open to discussion what role exposure of cosmic radiation, numbers of block-hours flown, or lifestyle factors—such as possible excessive sunbathing—play in the aetiology of cancer among pilots. This calls for further and more powerful studies. The excess of malignant melanoma among those flying over five time zones suggests that the importance of disturbance of the circadian rhythm should be taken into consideration in future studies.


Keywords: cancer registry; malignant melanoma of the skin; cosmic radiation; block-hours; time zones