Migration and death from malignant melanoma

Review of Wearable and Portable Sensors for Monitoring Personal Solar UV Exposure

Sunlight is one of the main environmental resources that keeps all the organisms alive on earth. The ultraviolet (UV) radiation from the sun is essential for vitamin D synthesis in the human body, which is crucial for bone and muscle health. In addition, sun exposure also helps to reduce the risk of some cardiovascular diseases and cancers. However, excessive UV exposure can lead to adverse effects, including some eye diseases, premature aging, sunburn and skin cancers. The solar UV irradiance itself depends on many environmental factors. In fact, the UV index reported in weather forecasts is an estimation under cloudless conditions. Personal UV exposure also depends on one's outdoor activities and habits. Furthermore, the UV intake depends on the skin sensitivity. Therefore, there is a need for research into monitoring the optimal daily UV exposure for health benefits, without developing potential health risks. To facilitate the monitoring of solar UV intensity and cumulative dose, a variety of UV sensors have been developed in the past few decades and many are commercially available. Examples of sensors being marketed are: portable UV dosimeter, wearable UV radiometer, personal UV monitor, and handheld Solarmeter®. Some of the UV sensors can be worn as personal health monitors, which promote solar exposure protection. The paper provides a comprehensive review of the wearable and portable UV sensors for monitoring personal UV exposure, including a discussion of their unique advantages and limitations. Proposals are also presented for possible future research into reliable and practical UV sensors for personal UV exposure monitoring.

Basal Cell Carcinoma: Review of Epidemiology, Pathogenesis, and Associated Risk Factors

Background:

Basal cell carcinoma (BCC) is extremely common, and its incidence continues to rise.

Objective:

This review presents the literature pertaining to the epidemiology, pathogenesis, and risk factors associated with BCC.

Conclusions:

The risk of developing BCC depends on both genetic predisposition and exposure to risk. Fair-skinned people account for the overwhelming majority of patients, beyond what would be expected by skin phototype alone. Damage to multiple lines of defense appears to be necessary for cancer development and spread. This damage distorts the concerted effort of deoxyribonucleic acid (DNA) repair, immunosurveillance, and cellular growth regulation to protect against malignant progression. Ultraviolet light exposure is the most critical modifiable factor determining early expression and frequency of BCC development.

European Code against Cancer 4th Edition: Ultraviolet radiation and cancer

Ultraviolet radiation (UVR) is part of the electromagnetic spectrum emitted naturally from the sun or from artificial sources such as tanning devices. Acute skin reactions induced by UVR exposure are erythema (skin reddening), or sunburn, and the acquisition of a suntan triggered by UVR-induced DNA damage. UVR exposure is the main cause of skin cancer, including cutaneous malignant melanoma, basal-cell carcinoma, and squamous-cell carcinoma. Skin cancer is the most common cancer in fair-skinned populations, and its incidence has increased steeply over recent decades. According to estimates for 2012, about 100,000 new cases of cutaneous melanoma and about 22,000 deaths from it occurred in Europe. The main mechanisms by which UVR causes cancer are well understood. Exposure during childhood appears to be particularly harmful. Exposure to UVR is a risk factor modifiable by individuals' behaviour. Excessive exposure from natural sources can be avoided by seeking shade when the sun is strongest, by wearing appropriate clothing, and by appropriately applying sunscreens if direct sunlight is unavoidable. Exposure from artificial sources can be completely avoided by not using sunbeds. Beneficial effects of sun or UVR exposure, such as for vitamin D production, can be fully achieved while still avoiding too much sun exposure and the use of sunbeds. Taking all the scientific evidence together, the recommendation of the 4th edition of the European Code Against Cancer for ultraviolet radiation is: "Avoid too much sun, especially for children. Use sun protection. Do not use sunbeds."

UV and children's skin

There is indicative epidemiological evidence that exposures of children younger than about 10 years are linked with an increased risk of the development of malignant melanoma as well as non-melanocytic skin cancers later in life. However, an important area of uncertainty relates to lack of knowledge of the sun-sensitivity of children's skin both absolutely and relative to that of adult's skin. For example the thickness of children's skin is very similar to that of adults but due to the nature of the anatomical structure of children's skin, there are indications of children's skin being adversely exposed on the top of the papilla before a significant exposure manifests itself as visible damage to the skin (for example erythema). This might also affect the induction of heavily UV-damaged cells persisting in the basal layer of the epidermis after UV-exposure which are supposed to be keratinocytic epidermal stem cells and may characterize an initiation step of non-melanoncytic skin cancer. For malignant melanoma the number of nevi received in dependence of UV-exposure in childhood is a clear risk factor. Recent data show that the bulge region of hair follicles hosting melanocytic stem cells are located deeper (more protected) in the skin in adults (terminal hair) as compared to pre-pubertal children (vellus hair). This may be an explanation for enhanced risk of malignant melanoma due to UV-exposure in pre-pubertal childhood.

BRAF mutations in cutaneous melanoma are independently associated with age, anatomic site of the primary tumor, and the degree of solar elastosis at the primary tumor site

Oncogenic BRAF mutations are more frequent in cutaneous melanoma occurring at sites with little or moderate sun-induced damage than at sites with severe cumulative solar ultraviolet (UV) damage. We studied cutaneous melanomas from geographic regions with different levels of ambient UV radiation to delineate the relative effects of cumulative UV damage, age, and anatomic site on the frequency of BRAF mutations. We show that BRAF-mutated melanomas occur in a younger age group on skin without marked solar elastosis and less frequently affect the head and neck area, compared to melanomas without BRAF mutations. The findings indicate that BRAF-mutated melanomas arise early in life at low cumulative UV doses, whereas melanomas without BRAF mutations require accumulation of high UV doses over time. The effect of anatomic site on the mutation spectrum further suggests regional differences among cutaneous melanocytes.

The risks and benefits of sun exposure: should skin colour or ethnicity be the main variable for communicating health promotion messages in New Zealand?

OBJECTIVE

Using New Zealand as a case study, to determine whether ethnicity is appropriate for communicating sun exposure health promotion messages.

DESIGN

This study reviews recent literature on minimising skin cancer risk and achieving sufficient serum vitamin D levels. It draws on a variety of scientific literature, reports and media statements to determine appropriate sun exposure messages for minimising skin cancer risk and achieving sufficient vitamin D status among the New Zealand population, which is diverse with regards to both ethnicity and skin colour.

RESULT(S)

Due to a unique combination of factors, New Zealand and Australia lead the world in melanoma incidence. Devising ways of minimising skin cancer risk and achieving optimal vitamin D blood levels among the New Zealand population provide major challenges for researchers and health promoters. These challenges include the many unknowns and uncertainties about vitamin D, such as determining what constitutes an optimal level as well as its association with specific diseases. There is strong evidence that skin cancer, including melanoma, is caused by excess harmful sun exposure with skin colour having long been established as a risk factor. More recently, there has been significant focus in New Zealand on the potential beneficial aspects of sun exposure, mainly in assisting vitamin D synthesis, especially for Maori and Pacific people. But research also shows that Maori and Pacific people are increasingly at risk of developing melanoma. In New Zealand, where there is a high rate of ethnic intermarriage and ethnicity is culturally constructed, there is likely to have been a weakening of the relationship between ethnicity and skin colour. Skin colour information is required to understand both the risks and benefits of sun exposure. In the immediate future, ethnicity appears likely to remain an important reference point for assessing the risks and benefits of sun exposure in New Zealand. However, we contend that while ethnic-based channels may be useful for communicating appropriate sun exposure messages, there are dangers in such advice based on membership of particular ethnic group(s). Rather skin colour, along with other key variables, such as season and time of day, should be the core considerations for assessing and discussing risk. In the longer term, direct measures of skin type are needed when assessing the risks and benefits of sun exposure, including the potential protective effects against various illnesses.

CONCLUSION

While ethnic-based dissemination channels may be useful for communicating about the risks and benefits of sun exposure in New Zealand, discussion of risk factors should focus on skin colour.

Treatment and outcomes of melanoma in acral location in Korean patients

PURPOSE

A retrospective study was conducted to review the treatment and outcomes of mainly melanomas in acral location in a single institution in Korea, and to evaluate the prognostic significance of anatomic locations of the tumor.

MATERIALS AND METHODS

A retrospective review was completed on 40 patients between 2001 and 2006 to obtain pertinent demographic data, tumor data, treatment characteristics, and follow-up data.

RESULTS

Forty melanoma patients were identified and analyzed. Of these, 18 were male and 22 were female patients and the mean age at the time of diagnosis was 55.9 years. Of the tumors, 65% were located on the hands and feet with acral lentiginous melanoma being the most common histological subtype. Univariate analysis for the overall melanoma survival revealed that the thickness of the tumor and the clinical stage have prognostic significances. The most significant factor as analyzed by a multivariate analysis was shown to be the advanced clinical stage. Acral melanomas did not show statistically significant differences in the age at diagnosis, thickness of the tumor, stage, ulceration, and survival rates compared to non-acral melanomas. There was also no significant difference in the survival rate between the patients treated by amputation versus wide local excision in acral melanomas.

CONCLUSION

In Korean melanoma patients, thickness and advanced stages are significant factors for poorer prognosis. However, the location of melanoma did not have a significant prognostic value. In treating the melanomas in acral location, local wide excisions resulted in a similar prognosis compared to amputations.

Skin cancer in skin of color

Skin cancer is less common in persons with skin of color than in light-skinned Caucasians but is often associated with greater morbidity and mortality. Thus, it is crucial that physicians become familiar with skin cancer in persons of color so as to maximize the likelihood of early detection of these tumors. In dark-skinned ethnic groups, squamous cell carcinoma is most common; squamous cell carcinoma and melanoma usually occur on nonsun-exposed sites; and ultraviolet radiation is not an important etiologic factor for skin cancer with the exception of basal cell carcinoma. Races of intermediate pigmentation, such as Hispanics and Asians, share epidemiologic and clinical features of dark-skinned ethnic groups and Caucasians. Skin cancers pose a significant risk in skin of color and clinicians should focus on preventive measures in these groups such as regular skin exams, self-examination, public education, and screening programs.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with the epidemiology and unique clinical features of skin cancer in skin of color and be aware of strategies to prevent skin cancer in skin of color.

Sun exposure and risk of melanoma

BACKGROUND

As skin cancer education programmes directed to children and adolescents continue to expand, an epidemiological basis for these programmes is necessary to target efforts and plan for further evaluation.

AIMS

To summarise the epidemiological evidence on sun exposure during childhood and adolescence and melanoma risk.

METHODS

A literature review was conducted using Medline (1966 to December 2004) to identify articles relating to sun exposure and melanoma. The review was restricted to studies that included sun exposure information on subjects 18 years of age or younger.

RESULTS

Migrant studies generally indicate an increased melanoma risk in individuals who spent childhood in sunny geographical locations, and decreasing melanoma risk with older age at arrival. Individuals who resided in geographical locations close to the equator or close to the coast during childhood and/or adolescence have an increased melanoma risk compared to those who lived at higher latitudes or never lived near the coast. The intermittent exposure hypothesis remains controversial; some studies indicate that children and adolescents who received intermittent sun exposure during vacation, recreation, or occupation are at increased melanoma risk as adults, but more recent studies suggest intermittent exposure to have a protective effect. The majority of sunburn studies suggest a positive association between early age sunburn and subsequent risk of melanoma.

CONCLUSION

Future research efforts should focus on: (1) clarifying the relation between sun exposure and melanoma; (2) conducting prospective studies; (3) assessing sun exposure during different time periods of life using a reliable and quantitative method; (4) obtaining information on protective measures; and (5) examining the interrelations between ability to tan, propensity to burn, skin type, history of sunburns, timing and pattern of sun exposure, number of nevi, and other host factors in the child and adolescent populations.

Timing of excessive ultraviolet radiation and melanoma: epidemiology does not support the existence of a critical period of high susceptibility to solar ultraviolet radiation- induced melanoma

BACKGROUND

The existence of a 'critical period' early in life characterized by a high susceptibility to melanoma initiation due to excessive ultraviolet (UV) radiation has been suggested by various authors based on epidemiological findings from migration studies and some case-control studies. However, the evidence so far is controversial as several epidemiological investigations failed to corroborate these results. Objective To compare the increase in melanoma risk due to excessive UV radiation between different periods in life.

METHODS

In a multicentre case-control study we recruited 603 melanoma cases and 627 population controls in seven European countries. We obtained data on the history of sunburns during 'childhood' (</= 15 years) and 'adulthood' (> 15 years), respectively, in standardized personal interviews. We employed logistic regression analyses to estimate the impact of the exposure factors under study, while simultaneously controlling for the effect of a variety of confounding variables.

RESULTS

We found a very similar upward gradient of melanoma risk in exposure categories related to the frequency of sunburns during both periods in life. More than five sunburns doubled the melanoma risk, irrespective of their timing in life.

CONCLUSIONS

Our data do not provide supporting evidence for the existence of a 'critical period'. The hazardous impact of sunburns seems to persist lifelong and thus activities concerned with melanoma prevention should be directed to the entire population rather than being focused only on younger age groups.

The health impact of solar radiation and prevention strategies: Report of the Environment Council, American Academy of Dermatology

It is well recognized that exposure to solar radiation is a major risk factor for the development of skin cancer, photoaged skin, and immune system alterations. However, major questions remain regarding the specific wavelengths and type of exposure that incur risk. The purpose of this article is to critically examine, on the basis of current knowledge, the impact of stratospheric ozone depletions, tanning bed skin cancer risk, the safety of sunscreens as an important element of our solar protection strategies, the wavelengths of solar radiation responsible for melanoma, and the incidence of melanoma. Recommendations are made on prevention strategies and public health messages.

A clinical review of the evidence for the role of ultraviolet radiation in the etiology of cutaneous melanoma

Strong epidemiological evidence exists that solar radiation is causally related to a significant proportion of cutaneous melanoma. The nature of the relationship is, however, complex and the details are not entirely clear. There appears to be a complex interplay between solar exposure in individuals with a characteristic phenotype. Although the exact quantitative and qualitative nature of this exposure is not clear, it is probable that intermittent exposures and intense exposures with consequent sunburns in a high-risk phenotype are critical in increasing the risk of developing melanoma. Despite the lack of complete understanding of this relationship, the evidence is convincing that solar radiation is causally related to cutaneous melanoma and consequently exposures to UV radiation should be reduced from early in life. The preventive measures involve reducing exposure to ambient solar radiation, by avoiding peak exposures, wearing protective outerwear, and using broad-spectrum sunscreens.

The epidemiology of skin cancer

BACKGROUND

The incidence of skin cancer is increasing at an alarming rate.

OBJECTIVE

To discuss current epidemiologic data concerning the incidence, morbidity, environmental influences, predisposing, host conditions, precursor lesions, and prevention of melanoma and nonmelanoma (basal and squamous cell) skin cancer.

METHODS

The current literature was reviewed in order to provide current epidemiologic data for melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC).

RESULTS

Skin cancer is exceedingly common and the incidence is rising rapidly. Although the mortality rate for nonmelanoma skin cancer (NMSC) is decreasing, that of melanoma is increasing. Both NMSC and melanoma are associated with significant morbidity. Whereas chronic sun exposure is the main cause of NMSC, the development of melanoma appears to be related to intense, intermittent sun exposure. Ozone depletion has contributed to rising incidence rates of both NMSC and melanoma. In contrast to NMSC, there is not a direct relationship between ultraviolet radiation and melanoma. Genetic susceptibility significantly increases the lifetime risk of acquiring melanoma. There is no precursor lesion for BCC. Precursor lesions for invasive SCC include actinic keratoses and SCC in situ. Melanoma may arise from benign nevi and dysplastic nevi. Prevention of melanoma and NMSC is extremely important since prognosis improves with early detection. Prevention may be achieved by educating patients and physicians how to detect skin cancers early and by decreasing or eliminating exposure to ultraviolet light.

CONCLUSION

The incidence of skin cancer has reached epidemic proportions. Only through heroic efforts by health care professionals and the general public to prevent the development or progression of skin cancer will this epidemic be abated.

Primary school children's perceptions of the effects of sun on skin

To assess whether young children understand the dangers and results of sun exposure, a novel Draw and Write technique was used to survey a group of 5-8 year old primary school children. One hundred and ninety-four children were invited to draw and write comments to six scenarios involving sun exposure. Of the children surveyed, 84% gave a negative sentiment to sunburn, with only 6% displaying positive sentiments towards sunbathing. Sixty-five per cent of children suggested the use of sun blocks, 69% the use of protective clothing, 45% the wearing of hats and 43% the use of shade as a mechanism for protecting the skin from sun damage. Only 2% of children made any reference to skin cancer. The primary school children surveyed had a good level of awareness of the dangers of sunburn and the need to take appropriate actions to avoid sun damage.

An addition to the controversy on sunlight exposure and melanoma risk: a meta-analytical approach

Case control studies on the association between sunlight exposure and melanoma risk show considerable differences in design; this could be responsible for the variation in study results. In an attempt to resolve the controversy between study results, the results of 25 publications on case control studies were evaluated using meta-analytical techniques. Comparison of odds ratios between subgroups of studies revealed that the range of odds ratios was far greater for hospital-based studies than for population-based studies. For the latter type of studies, the odds ratios were homogeneous and the pooled odds ratios were 1.57 (95% confidence interval [CI], 1.29-1.91) for intermittent sunlight exposure and 0.73 (95% CI, 0.60-0.89) for chronic exposure. However, among other problems, the lack of standardized measures for sunlight exposure warrants cautious interpretation of these results. It is concluded that evidence to support the intermittent sunlight theory is still far from complete.

Cancer incidence in England and Wales and New Zealand and in migrants between the two countries

Risks of cancer incidence in people born in England and Wales and New Zealand (non-Maoris) living in their home countries, and after migration between the two countries, were analysed using data from their national cancer registries. Since these populations are of similar genetic origin, any real differences in cancer incidence between them are likely to reflect the action of environmental or behavioural risk factors. The greatest differences in risk between the countries were for cutaneous melanoma and lip cancer. In each sex, relative risks of these malignancies were 4 or greater for the New Zealand-born in New Zealand compared with English and Welsh natives in their home country, and risks for migrants in each direction were generally intermediate between those born in the home country in the two countries. Sizeable significantly raised risks in the New Zealand-born in New Zealand compared with English and Welsh natives in England and Wales also occurred for cancers of the mouth, small intestine, colon, thymus, eye and thyroid, and non-Hodgkin's lymphoma in each sex, and for cancer of the prostate. For all of these sites except mouth, small intestine and colon there were also risks around or above New Zealand-born levels for English and Welsh migrants to New Zealand; for colon cancer these migrants had risks close to those in England and Wales. New Zealand migrants to England and Wales had risks of cancers of the colon and prostate that were similar to or above New Zealand levels. Risks of cancers of the stomach, lung, pleura and bladder, and Hodgkin's disease in each sex, and cancers of the cervix, ovary and scrotum and penis, were substantially and significantly lower in the New Zealand-born living in New Zealand than in English and Welsh natives in England and Wales. In English and Welsh migrants to New Zealand risks of bladder cancer in each sex, and of scrotal and penile and pleural cancer in males, approximated to England and Wales risks; cervical cancer risk approximated to the New Zealand risk; and stomach, lung and ovarian cancers showed intermediate risks. Migrants from New Zealand to England and Wales did not gain the lung cancer or clearly the stomach cancer risk of their host country, but did have bladder cancer risks approximating to those in England and Wales.(ABSTRACT TRUNCATED AT 400 WORDS)

Sun exposure and melanocytic naevi in young Australian children

Queensland, Australia, has the highest rates of melanoma in the world and Queensland children have the greatest numbers of melanocytic naevi, the strongest risk factor for melanoma. Although both melanoma and naevi are broadly related to sun exposure in childhood, the relation to individual exposure early in life is difficult to study retrospectively in adults. We surveyed 506 children aged 1-6 years who had been born in Townsville, North Queensland. Sun exposure was assessed by questionnaire and melanocytic naevi were counted using a standard international protocol. Very high counts (upper quarter) of melanocytic naevi were significantly associated with sun exposure of more than 4 hours per day (adjusted relative risk ratio 3.29; 95% Cl 1.12-9.69), and with a history of sunburn (1.89; 1.11-3.21). Melanocytic naevus counts increased with age, light skin reflectance, and freckling. With exposure to intense ultraviolet light in Townsville, children develop melanocytic naevi early in life and in large numbers. We found that both acute and chronic exposure to sun are associated with their development.

Biochemical parameters of epidermal aging in the hairless mouse and the relationship to UV-carcinogenesis

Epidemiological studies suggest that the incidence of cancer increases with age in both human and animal populations and that declining physiologic condition associated with aging might be responsible. Experimentally, the reverse has been most often observed, that is, older animals appear less susceptible to the induction of UV-carcinogenesis. Thus, we examined several biochemical parameters of epidermal macromolecular synthesis in hairless mice in an effort to gain insight into the role these processes play in physiological aging and their relationship to carcinogenesis. SKh-Hr-1 hairless mice were randomized into two groups (UV-irradiated and non-irradiated controls) and were two months of age at the start of irradiation and biochemical analyses. The UV group received 0.028 sunburn units (SBUs) daily (5 days wk-1) for 16 months from 40 watt BZS-WLG lamps. Stratum corneum turnover rates (SCR), cell label index (CLI), protein, DNA and RNA synthesis, and ornithine decarboxylase (ODC) induction were determined at monthly intervals over a period of two years. There were no age-related tendencies observed in SCR. CLI increased with age. Chronic, low-dose UV had no effect upon either of these parameters. Epidermal capacity for DNA and protein synthesis increased with age from 2 months to 12-15 months at which time both parameters peaked and then began to decline. UV significantly reduced (P < 0.04) the magnitude of DNA synthetic capacity at peak periods of synthesis but had no effect upon protein synthesis. RNA synthetic rates declined with age, reaching their lowest levels at 24 months. Further, a significant reduction (P < 0.001) in ODC inducibility occurred with advancing age.(ABSTRACT TRUNCATED AT 250 WORDS)

At what age do sunburn episodes play a crucial role for the development of malignant melanoma

The age relationship between sunburns and malignant melanoma was investigated in a population-based, matched, case-control study from the South Swedish Health Care Region (the highest risk area for melanoma in Sweden). Between 1988 and 1990, a total of 400 patients with a first diagnosis of malignant melanoma and 640 healthy controls aged 15-75 years answered a comprehensive questionnaire including questions regarding ultraviolet radiation exposure. In addition, a literature review was performed. The average number of episodes of sunburn per year was significantly associated with malignant melanoma (relative risk, RR = 1.9 for > or = three episodes per year versus never). Outdoor employment during the summer was associated with a decreased risk for the development of malignant melanoma (RR = 0.8). Data from case-control studies and migration studies concerning age relationship between sunburns and melanoma are inconsistent. From our own data, we did not find a higher risk of melanoma developed in individuals who had experienced severe sunburns in childhood. Instead, a significantly increased risk was associated with sunburns after age 19 years, RR = 2.2 for a history of more than five times versus never. Even if the hypothesis is biologically plausible, that episodes of sunburn early in life are associated with a higher risk of melanoma, so far epidemiological evidence is scarce. There is a need for better prospective epidemiological studies addressing this issue.

Etiology of melanoma

Although the precise etiology of melanoma remains unknown, much data link sunlight to melanoma. The imperfect evidence associating sun exposure (particularly UVB radiation) with melanoma emerges from human data, obviating problems inherent in extrapolation from animal and other models. However, the mechanism by which sunlight might possibly initiate or promote melanoma remains obscure. Some clarification should emerge from the potential isolation of genes that carry susceptibility to melanoma in families prone to the disease; such work could serve as a basis to distinguish genetic and environmental influences in melanoma [167]. Continued studies of faulty DNA repair in XP patients may elucidate the steps in mutagenesis and carcinogenesis. Future case-control studies must address the limits on the accuracy of recall and the limits on statistical methods to separate the cluster of phenotypic risk needed in determining biologically effective dose. Animal and in vitro studies must contribute more insight. Further research in the South American opossum models appears promising [72]. Although ozone depletion has been documented, there has been little definitive evidence of subsequent increase of UVB at the Earth's surface. Nevertheless, the threat posed by ozone depletion deserves continued environmental action and public education. The role of precursor lesions, particularly dysplastic nevi/atypical moles, must be clarified with future research. The distribution of melanoma among various work forces suggests that occupational risk factors may play an important role in the etiology of this disease [168-170]. The consistent reports of excess melanoma among accountants, clerical workers, professional workers, and teachers deserve further study. Furthermore, evidence of excesses in printing and press, petrochemical, and the telecommunications industries require follow-up. Carefully planned studies that account for nonoccupational risk factors are recommended. Research over the last four decades has brought much information about melanoma etiology. More work is needed to learn the precise cause and ultimately to prevent avoidable mortality from malignant melanoma.

Cutaneous melanoma and sunburns in childhood in a southern European population

A population-based case-control study of 260 patients (74 males and 186 females, mean age = 56) with cutaneous malignant melanoma and 416 controls (211 males and 205 females, mean age = 55) was conducted in Turin, north-west Italy, to examine the relation between timing of sunburns and sun exposure and melanoma risk within a southern European population, which is still relatively little investigated. Particularly elevated risk was associated with history of sunburns in childhood [odds ratio 5.9; 95% confidence interval (CI) 3.6-9.5], and such risk elevation persisted after allowance for other major melanoma risk covariates. Conversely, risk increase from history of severe sunburns lifelong was lower (odds ratio = 1.7; 95% CI: 1.1-2.4) and was eliminated by allowance for type of skin reaction to sun exposure and history of sunburns in childhood. A significant increase in the risk of cutaneous malignant melanoma was also associated with number of weeks spent on holiday at the beach not only as an adult, but also as a child.

Malignant melanoma risk by nativity, place of residence at diagnosis, and age at migration

Although geographic latitude is clearly linked to the risk of cutaneous malignant melanoma, the chronology of this link is unclear. Based on the 4,611 cases of melanoma with known place of nativity diagnosed in 1972-82 among the non-Latino White residents of Los Angeles County (California, United States) of known place of origin, migrants to Los Angeles from higher US latitudes enjoy relative safety from skin melanoma. This relative safety is largely unaffected by the interval since migration, even after decades of residence in Los Angeles. The same relative protection is enjoyed by native residents of more northerly US communities in comparison with co-resident migrants from the southwestern US. While the observed effect of latitude is consistent with the accepted importance of solar radiation as a determinant of melanoma risk, it suggests that early, rather than late or cumulative, exposure is of most importance. This finding does not affirm the belief that protection of adult skin from exposure to the sun will reduce the risk from melanoma. It does suggest that decades must pass before it will be possible to assess the impact on melanoma risk of any increase in ultraviolet radiation delivered to the earth as a result of the destruction of atmospheric ozone.

Indications of future decreasing trends in skin-melanoma mortality among whites in the United States

Trends in skin melanoma death rates during a 35-year period, 1950-84, were analyzed according to age, sex, and birth cohort for whites in the United States. In contrast to upward trends observed for older men and women (i.e., over 40), downward trends were noted for younger age groups. The risk of dying from skin melanoma appears to have peaked for male cohorts born during the 1950s and for female cohorts born during the 1930s. Assuming no future environmental or lifestyle changes, the upward trend in age-adjusted mortality rates, which averaged 2 to 3% per annum since 1950, is projected to discontinue and bend downward by the second decade of the 21st century. Skin melanoma incidence data, which was limited to a series of 12 years (1973-84) and inadequate for cohort analyses, were included to demonstrate that trends in age-specific rates were comparable with those observed for mortality during the overlapping time period. Incidence trends according to anatomical site are also described. These results indicate that baseline data necessary for assessing the potential effects on this disease from future depletions of the ozone layer, and predicted increases of solar ultra-violet radiation exposure, would be improved with the inclusion of cohort data and age-specific trend analyses.

Early detection and prevention of cutaneous malignant melanoma: emphasis on Swedish activities

The incidence of cutaneous malignant melanoma has increased more than the incidence of any other malignant tumour disease in Sweden the last three decades. Parallel to the almost 6% annual increase in incidence there has been a 3% annual increase in mortality. The knowledge of significant risk factors for melanoma (intermittent sun exposure and phenotypic traits related to skin pigmentation and propensity for dysplastic nevi) as well as the relationship between thin tumours and a good prognosis has been used to develop strategies for primary and secondary prevention. In this paper the Swedish programs for education of physicians, nurses and the general population are presented. A nationwide program for the identification and follow-up of individuals with dysplastic nevus syndrome has been initiated. The effects of the programs are followed by population-based melanoma registries.

The relationship between malignant melanoma of skin and exposure to sunlight

Malignant melanomas of the skin are becoming more common. Earlier diagnosis has led to better individual prognoses, but this has not prevented the death rate in the population from rising. This paper brings up-to-date studies on the etiology of malignant melanoma, and supplements various fuller but earlier reviews. Melanoma risk is increased in lightly pigmented people who burn in the sun and do not tan well. People with an increased number of nevi are also at increased risk. Latitude of residence is important, risk in white populations increasing with distance from the poles. Phenotypic factors can over-ride location, so that Mediterranean people have lower rates than Scandinavians. Melanomas are concentrated on sites exposed by clothing, but this concentration is not as strong as for the other skin cancers. Migrants to sunny climates are at less risk than similar people born locally, provided that they migrated as adults. Outdoor work carries only a small excess risk of malignant melanoma, in contrast to the other skin tumors. Melanomas are commoner, and kill more often, among people of high socioeconomic status than low. The two most detailed contemporary reconciliations of these pieces of evidence are based on the ideas that intense brief exposure is the critical factor, or that exposure in childhood is of major importance. With the expected changes in the global concentration of ozone in the stratosphere, it is necessary to estimate the relationship between the intensity of sunlight and melanoma risk.