Current PerspectivePerspectives in melanoma prevention: the case of sunbeds
Introduction
The incidence of cutaneous malignant melanoma (melanoma) has steeply increased in the past 50 years in most fair-skinned populations. For instance, from 1970 until 1997, a 2.5-fold increase in melanoma incidence was observed in Finland, and a 3.6-fold increase in White Americans [1], [2]. From 1979 until 1998, a 2.4-fold increase was observed in Scotland [3], and from 1980 and 2000, a 2.8-fold increase was estimated for France [4]. Risk factors for the basal cell carcinoma (BCC) are similar to risk factors for melanoma [5]. The incidence of BCC is also increasing sharply in most fair-skinned communities, mainly in females [6].
The fashion of intermittent sun exposure that took place after 1950 is considered as the main cause of the increases in melanoma and in BCC. The depletion in ozone observed in the stratospheric layers of the atmosphere is not likely to contribute to the raising incidence of these skin cancers. The ultraviolet (UV) radiation is deemed to represent the part of the solar spectrum involved in the genesis of melanoma [7]. In spite of increasing knowledge on the association between sun exposure and the considerable rise in skin cancer incidence, exposure to artificial sources of UV radiation has become popular in all fair-skinned populations around the world. These artificial sources of UV radiation have various denominations, e.g., tanning machines, UVA-tanning devices, indoor tanning, sunbeds, and solarium. The sunbed fashion could contribute to the increase in skin cancer occurrence, in particular, of melanoma [8].
In this paper, we delineate the public-health issues involved in sunbed use in 2004, and we stress the need to promote actions going beyond the regulations of sunbed use, especially actions aiming at controlling the information disseminated by the “tanning industry” on supposed safety and hypothetical health benefits of sunbed use.
Section snippets
Sunbed use is an intentional sun exposure behaviour
The melanoma epidemic affects mainly skin areas usually covered by clothes, like the trunk, shoulders and limbs, while lower increases in melanoma incidence are observed on the more chronically sun exposed body sites, like the head and neck [3], [9]. Likewise, the increase in BCC incidence is mainly observed on body sites that are not chronically exposed to sunlight [6]. This epidemiological feature points to the role attributed to the intermittent sun exposure in the genesis of most melanoma
The role of UVA and UVB in melanoma occurrence is still unknown
At present, there are no scientific data indicating that intentional exposure to UV radiations emitted by sunbeds is less harmful than intentional exposure to sunlight.
The UV radiation reaching the earth’s surface comprises UVB (280–319 nm) and UVA (320–400 nm) radiations. During a sunny day on the Mediterranean coast, the solar UV spectrum at noon contains approximately 5% of UVB and approximately 95% of UVA. UVB is far more efficient than UVA at inducing the synthesis of melanin, and
Epidemiological data on sunbed use and melanoma
As there is no valid animal model for human melanoma, and because we are still ignorant about the effects of UV radiation(s) and melanoma occurrence, the study of any eventual link between sunbed use and melanoma left to epidemiological investigations.
Seven epidemiological case-control studies specifically addressed the possible association between increasing amounts of sunbed use and melanoma [12], [15], [28], [29], [30], [31], [32]. Two reviews concerning six studies [33], [34] concluded that
Methodological limitations of case-control studies
In the seven case-control studies, exposure to sunbeds was assessed retrospectively, and compared between patients with melanoma (i.e., the cases) to subjects without melanoma (i.e., the controls). These case-control studies could suffer from three limitations:
- 1.
Case-control studies are not optimal designs for demonstrating an increase in Relative Risk when additive risks are small, i.e., an estimated Relative Risk of between 1.00 and 1.99.
- 2.
The answers of melanoma patients on their past sunbed use
Skin cancers other than melanoma
Two case-control studies examined past exposure to sunbeds in patients with non-melanoma skin cancer. One found no association [37]. Another found positive associations between sunbed use and SCC and BCC [38]. In the latter study, the estimated Relative Risk associated with sunbed use was 2.5 (95% CI: 1.7–3.8) for SCC and 1.5 (95% CI: 1.1–2.1) for BCC. These findings are in line with data on non-melanoma skin cancers in patients affected by severe psoriasis and treated with PUVA therapy (a
Regulations of commercialisation, installation, operation and use of artificial tanning devices
Since 1990, many countries have issued specific rules for sunbed installation, operation and utilisation. There is a wide variation in the content of these rules. In the European Union, there is no standardisation of regulations on sunbed commercialisation and use. In some countries (e.g., in the UK, Canada and the Netherlands), recommendations are formulated by, or in association with the sunbed industry, or organisations of professional sunbed operators. In the US, the Food and Drug
The tanning industry
The “tanning industry” can be understood as all commercial activities developed around the behaviours of intentional sun exposure, for tan acquisition or for other reasons like the search of well-being. Products promoted and sold by the tanning industry comprise sunscreens, a variety of oral preparations deemed to increase the resistance to UV aggressions or to facilitate tan acquisition, swim suits permeable to UV radiations, and the use of non-solar sources of UV presented as safe
The UV-lamps rich in UVB radiation
Recently, new fluorescent lamps that have an emission spectrum resembling the emission spectrum of the midday sun have been introduced into the market. Exposure to these lamps enables a faster acquisition of a deep tan. Exposure to UVB-rich lamps is similar to intentional sun exposure in the midday sun, and is thus likely to convey the same risk of skin cancer. Given the known association between intermittent sun exposure and melanoma, public-health authorities should reconsider the soundness
How credible is the precautionary principle?
The precautionary principle is frequently evoked in the shaping of health or of environmental policies. In brief, that principle consists of regulating the general public use or the diffusion in the environment of a substance or of a device whose safety remains open to question. In Europe, the precautionary principle is frequently put forward to oppose the development of innovations, even though there is no evidence for a detrimental impact on health or on the environment.
In spite of the
The need to control information disseminated by the tanning industry
For most people, information and advertisements disseminated by the tanning industry are the main source of information regarding tan acquisition and sun protection. Behavioural studies in Europe [17], [67], [68] show that people know about skin cancer and the damaging affect of sunbathing, and about possible dangers associated with sunbed use, but that knowledge does not alter their tanning behaviours in general. In Europe and the USA, recommendations on sunbed use and regulations restricting
Conclusions
The Norway–Sweden study [26] has provided epidemiological evidence that regular sunbed use is associated with a moderate increase in the risk of melanoma. Large numbers of people use sunbeds on a regular basis, and sunbed use often starts during adolescence. So, in 2004, UV doses accumulated by many people though sunbed use may be far higher than observed in the Norway–Sweden study.
Public-health efforts should continue to disseminate information on the dangers of UV radiations, and to
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