MELANOMA CRITICAL DEBATES - PART 2 pdf

sunbeds [6–10]. These figures may rise to 50% in countries such as Sweden [11,12]. A market survey carried out in Denmark in 1996 (AC Nielsen-AIM, Copenhagen, 1997) showed that 11% of subjects, aged 13 years or more, re- ported use of sunbeds less than once each month, 8% used sunbeds 1–3 times per month, and 5% used sunbeds at least once every week. The latter data indicate that a non-negligible proportion of the population may receive huge amounts of UV through sunbed use. A study has estimated that Swedish adolescents received annual total dosage of UV from sunbeds comparable to dosage received from the sun [13]. In the last few years, the indoor tanning fashion has rapidly extended in Mediterranean areas, such as the north of Italy, and in countries with an emerging economy, such as Argentina [14]. A substantial proportion of sunbeds are used in private facilities, and homemade solaria are not uncommon. The popularity of indoor tanning is rooted in the perceived cosmetic and psychological benefits of acquisition or maintenance of a healthy, attractive look [15]. There is also a widespread belief that acquisition of a prevacation tan may protect against the harmful effects of the sun. There is a possibility that another strong motive for sunbed use would be the ability of UV exposure (especially high UVA doses) to induce a sensation of well-being, mediated by the synthesis of enkephalin in the skin, that enters the bloodstream and then influences the central nervous system [16]. Relationship between indoor tanning and skin lesions and melanoma Clinical data Numerous clinical reports have been published about the deleterious effects of exposure to sunlamps/sunbeds on the skin (for a review see Spencer & Amonette [17]) and on the eye [18]. Severe skin burns have be seen in subjects who used photosensitizing drugs or skin lotions to foster their tanning ability (e.g. the psoralens) [19]. In the absence of valid animal models for human melanoma, epidemiologi- cal studies are mandatory for producing the most convincing documentation of an association between sunbed use and melanoma. Epidemiological data Epidemiological investigation of the possible association between sunbed use and skin malignancy faces the challenging question of how to recognize now a current exposure that could become recognized as a major carcinogenic haz- ard in the future? Three aspects must be carefully born in mind when reading 18 CHAPTER 2 the epidemiological literature on this topic. First, the latency period between exposure to a potentially carcinogenic agent and melanoma occurrence may be 20 or 30 years. Sunbed use is an exposure that has become more frequent in the last 20 years, so the impact on melanoma incidence may not be detectable before the year 2000 or 2010. Secondly, the existence of a latency period may lead to an underestimation of the actual association between indoor tanning and melanoma. Because the carcinogenic effect of more recent exposure is not yet detectable, a lack of dis- tinction between ancient and recent exposures may mask the actual increase in risk. As shown in a theoretical example displayed in Table 2.1, the masking effect will be more pronounced if recent exposures are more frequent than ancient exposures. The disease–exposure association only appears when ancient and recent exposures are distinguished. Thirdly, sunbed users have a greater propensity than average to enjoy recreational sun exposure [7]. Hence, statistical analysis of epidemiological data should always adjust risk estimates for recreational sun exposure. Results from epidemiological studies At least 19 epidemiological investigations have examined the association between cutaneous melanoma and exposure to sunlamps or sunbeds (re- viewed by Swerdlow & Weinstock [20]). Most of these studies only examined whether at least one exposure to sunlamp/sunbed was associated with cutaneous melanoma, and produced negative answers. These results are not highly informative because of the masking effect of recent sunbed exposures (Table 2.1). Since 1979, five epidemiological case–control studies have explored in more detail the relationship between exposure to sunlamps/sunbeds and cuta- neous melanoma (Table 2.2) [6,11,21–23]. These studies mainly addressed the significance of the use of sunlamps or sunbeds during the 1980s, when the ARE SUNBEDS DANGEROUS? 19 Table 2.1 Theoretical example of masking effect of recent exposures that have no detectable impact on a disease Recent Not exposed Exposed Ancient exposures exposures Cases 300 90 30 60 Controls 300 90 15 75 Estimated risk* 1.00 2.00 0.80 95% Confidence interval 0.71–1.41 1.01–3.99 0.54–1.18 *Risk is calculated as an odds ratio, always using the 300 cases and 300 controls not exposed as the reference group. indoor tanning fashion was in its early phase. In the Scottish and Ontario stud- ies, melanoma occurrence appeared more elevated among subjects who had ever exposed their skin to sunlamps/sunbeds. However, risk estimates were not adjusted for recreational sun exposure. The Swedish study [11] suggested a positive association between sunbed use and cutaneous melanoma among subjects less than 30 years old but, because of the small numbers of cases and controls in that age range, the association was not statistically significant. An association between indoor tanning and cutaneous melanoma risk is suggested by the following data. 1 The five studies found some degree of increasing melanoma risk with increasing sunlamp/sunbed exposure (Table 2.3). 2 In four studies (Table 2.4), the melanoma risk associated with sunbed use was systematically higher in subjects who had their first exposure many years before the diagnosis of melanoma, than in subjects with more recent exposures (the Swedish study [11] did not explore that aspect). 3 In the EORTC study [6], subjects who reported skin erythemal reactions caused by tanning sessions and more than 10h of accumulated exposure to sunlamp/sunbed displayed a sevenfold increase in melanoma, after adjust- ment for natural sun susceptibility and recreational sun exposure. The possible role of sunbed use in the aetiology of ocular melanoma has been examined by three epidemiological studies [24–26]. These three studies produced results consistent with a two- to fourfold increased risk for uveal melanoma associated with sunlamp/sunbed use. 20 CHAPTER 2 Table 2.2 Sunlamp or sunbed use and risk of cutaneous melanoma Estimated melanoma risk for ever vs. never Study place, year of publication [ref] exposed to sunlamp/ 95% Confidence (number of cases–controls) Study years sunbed interval Scotland, 1988 [29] 1979–84 2.9† 1.3–6.4* (180/120) Ontario, Canada, 1990 [30] 1984–86 Males: 1.88† 1.20–2.98* (583/608) Females: 1.45† 0.99–2.13 Sweden, 1994 [3] 1988–90 1.3‡ 0.9–1.8 (400/640) Belgium, France, Germany, 1994 [2] 1991–92 0.97† 0.71–1.32 (420/447) Connecticut, 1998 [23] 1987–89 1.13‡ 0.82–1.54 (624/512) *P £ 0.05. †Crude risk estimates. ‡Adjusted for natural sun sensitivity, sunburn history and exposure to sunlight. Discussion of epidemiological data The studies we reviewed indicated the possibility of an association between sunlamp/sunbed use and melanoma. The association could be the consequence of bias. For instance, melanoma patients might be more likely to remember past exposures to UV sources. The Ontario study performed a part of the interview before patients were told they ARE SUNBEDS DANGEROUS? 21 Table 2.3 Duration of exposure to sunlamp or sunbed and melanoma risk* Study place, year of Duration of Estimated publication exposure Cases Controls melanoma risk 95% CI Scotland, 1988 Never used 142 110 1.0§ — < 3 months 6 3 0.7 0.1–3.8 3 months–1 year 24 5 3.1 1.0–9.9 > 1 year 8 2 3.4 0.6–20.3 Test for linear trend: P= 0.0029 Ontario, 1990 Males Never used 210 242 1.00‡ — < 180 min 25 20 1.44 0.75–2.82 ≥ 180 min 39 18 2.50 1.34–4.80 Test for linear trend in males: P= 0.0012 Females Never used 222 256 1.00‡ — < 180 min 39 39 1.17 0.70–1.95 ≥ 180 min 38 27 1.62 0.91–2.89 Test for linear trend in females: P= 0.070 Sweden, 1994 Never used 282 479 1.0§ — 1–3 sessions 44 67 1.1 0.7–1.9 4–10 sessions 30 55 1.1 0.7–1.9 > 10 sessions 41 33 1.8 1.0–3.2 Test for linear trend: P= 0.020 Belgium, France, Germany, 1994† Never used 310 327 1.00§ — Exposure starts ≥ 1980 <10 h 36 45 0.75 0.46–1.25 ≥ 10 h 19 18 0.99 0.49–2.00 Exposure starts < 1980 <10 h 16 15 1.00 0.47–2.13 ≥ 10 h 18 7 2.12 0.84–2.12 Test for linear trend: P= 0.033 when start < 1980; P=0.89 when start ≥ 1980 Connecticut, USA, 1998 Never used 483 417 1.00§ — < 10 sunlamp uses 76 50 1.25 0.84–1.84 ≥ 10 sunlamp uses 63 40 1.15 0.60–2.20 Test for linear trend: P= 0.068 *Duration of exposure, relative risk, and 95% confidences as in published reports. The Mantel c 2 for trend was calculated by us. †The 21 cases and 35 controls who were exposed to sunlamp or sunbed for non-tanning purpose are not reported in this table. ‡Adjusted for age. §Adjusted for age, sex, natural sun-sensitivity and recreational sun exposure. had a melanoma, and concluded that recall bias was not likely to explain their findings [22]. Unfortunately, the Ontario study did not adjust risk estimates for sun exposure. Similarly, the positive trends described in Table 2.3 would need adjustment for recreational sun exposure and natural sun sensitivity be- fore making any firm conclusions. Also, timescales for expressing duration of sunlamp/sunbed exposure were variable between studies. Hence, method- ological aspects may partly explain results from epidemiological studies on sunbed exposure and cutaneous melanoma. Despite these limitations, the consistency in dose–response trends, the higher risk systematically found for most ancient exposures, as well as the melanoma risk associated with sunlamp/sunbed-induced skin erythema merit attention. These results are quite consistent with the hypothesis of a delayed impact of sunbed use on melanoma incidence because of the latency period of several decades between exposure to a carcinogenic agent and cancer occurrence. Sunbed use is capable of causing skin erythema and blistering, and UV- induced skin erythemal reactions (sunburns) are known risk factors for cuta- neous melanoma. Skin erythema or burns are reported by 18–44% of sunbed users, mainly by subjects with a poor ability to tan [6–8,11–12,17–27]. UVB is also known to be 1000 times more erythemogenic than UVA, and sunlamp/sunbed-induced erythemal reactions could be attributable to the UVB present in the tanning machine output [2]. In that respect, it could be argued that the higher melanoma risk observed with more ancient exposures (Table 2.3) could be attributable to the older type UV lamps that emitted 22 CHAPTER 2 Table 2.4 Ancient and recent exposure to sunlamp or sunbed and risk of cutaneous melanoma. These results were not reported in the Swedish study [11] Estimated melanoma risk (95% CI) First exposure more First exposure more Reference ancient recent Scotland, 1988 [29]† 9.1 (2.0–40.6)* 1.9 (0.6–5.6) Ontario, Canada, 1990 [30]† Males 2.00 (1.21–3.34)* 1.52 (0.56–4.25) Females 1.53 (0.96–2.46) 1.24 (0.67–2.31) Belgium, France, Germany, 1994 [2]‡ 2.12 (0.84–5.37) 0.99 (0.49–2.00) Connecticut, USA, 1998 [23]§ 1.33 (0.84–2.12) 1.15 (0.64–2.07) *P £ 0.05. †Five years since last use, unadjusted odds ratio for ever exposed vs. never exposed. ‡First exposure took place before 1980, odds ratio for 10 h of exposure or more vs. never exposed, adjusted for age, sex, natural sun-sensitivity and recreational sun-exposure. §Exposures £ 1970 are more ancient, and exposures after 1970 are more recent; adjusted for age, sex, natural sun-sensitivity, and recreational sun-exposure. significant amounts of UVB. However, in the EORTC and in other studies [6–8,10–12], skin erythema occurred after exposure to modern sunbeds. Also, high fluxes of UVA — commonly found in modern tanning machines — are capable of inducing skin erythemal reactions [28]. Because of the latency between exposure to carcinogenic agents and melanoma occurrence, epidemiological studies completed so far would have just been capable of examining the influence of exposures that took place when indoor tanning was less common. In that respect, only new studies will be able to reveal the eventual melanoma risk attributable to sunbed exposure that has became widespread after 1980. Medical use of ultraviolet radiation Ultraviolet radiation is used to treat a variety of skin diseases, such as psoria- sis. UV-based therapies occur in controlled conditions within the frame of scheduled treatment protocols. The UV spectra emitted by tanning equipment are wider that those used for treating skin diseases and it is not known whether the cutaneous responses of the average sunbed user resemble those seen in the skin of patients suffering from severe psoriasis. Thus, experience derived from UV-treated patients can hardly be transposed to indoor tanning for cosmetic or leisure purposes. One prospective study found an increased melanoma risk in patients suf- fering from severe psoriasis treated with a combination of UVA and psoralens (PUVA therapy) [29]. The increased risk was mainly apparent in psoriatic patients who had received 250 treatments or more. However, it was impossi- ble to ascertain which treatment component was implicated in the higher melanoma risk, as psoralens are potent photocarcinogens, and a proportion of patients received various other potentially carcinogenic treatments (e.g. coal tar). Is there a limit below which indoor tanning would be safe? At present it is not possible to define the cumulative time of exposure that would lead to increased melanoma risk. If assessable, this limit would be highly variable according to the UV spectrum emitted by a tanning machine and the individual sensitivity to UV radiation. Although epidemiological stud- ies provide clues to the amount of cumulative sunbed exposure possibly lead- ing to significant melanoma risk (Table 2.3), results are quite heterogeneous. The breakdown of risk by skin phototype is not available, and the time period during which sessions took place was not always analysed. Several expert groups have suggested maximum numbers of tanning sessions, but these are ‘best guess’ not supported by human data. For instance, in 1990, the British ARE SUNBEDS DANGEROUS? 23 Photodermatology Group recommended not to exceed a cumulative amount of 10 h of indoor tanning per year [30]. A document entitled ‘Outdoors and in- doors: sun wisely’, produced under the auspices of the Dutch Cancer Society [31], argues that sunbed exposure not exceeding 50 minimal erythemal doses (MED) per year is acceptable (1MED corresponds to the UV dose triggering a minimal skin erythema in a moderately sun-sensitive subject). A 30-min sunbed session represents an exposure to 0.7–1MED, and a 2-week summer holiday on the Mediterranean with regular sunbathing may represent a cumu- lative UV dose of 100MED. Hence, limits suggested for duration of sunbed exposure are well above the levels of sunbed exposure found to be possibly as- sociated with an increased melanoma risk (Table 2.3), and with sun exposure behaviours known to be associated with melanoma occurrence. Arguments often evoked for the defence of indoor tanning The sunbed industry, tanning enthusiasts and a fraction of the medical com- munity exploit several lines of argument to defend the use of artificial tanning devices. A more subtle position is the recognition of the good and bad effects of indoor tanning but that, on balance, good effects outweigh bad effects. Ar- guments put forward by indoor tanning advocates are often speculative and of questionable scientific validity, but they represent the core of most documents backing the commercialization of sunbeds, and the justification that indoor tanning is not an unacceptable health threat. Daily experience shows that these arguments are often accepted as true science by many doctors, institu- tions active in cancer prevention and decision makers. We review and briefly discuss the most important of them. The UV spectrum emitted by sunbeds is safer than the solar spectrum This argument suggests that a tan acquired through sunbed use would be safer than a tan acquired through sunbathing on a beach. It is largely based on the fact that compared to the summer Mediterranean sun, the UV spectrum of a modern sunbed contains between one and two times more UVA, and about half the amount of UVB [4]. However, the concept of a ‘safe tan’ is ill-founded and tanning with either UVB or UVA conveys a carcinogenic risk of similar order of magnitude [28,32]. The UV wavelength(s) involved in melanoma occurrence remain(s) unknown. Nevertheless, UVA is no longer regarded as an innocent radiation. An increasing number of data indicate that UVA is able to induce skin erythema, genetic damage, local and systemic immuno- suppression and skin malignancies in animals [1,28,33], and that it could be implicated in melanomaogenesis [34,35]. 24 CHAPTER 2 Recent studies suggest that tanning is a direct consequence of UV-induced DNA damage [36]. Substantial skin DNA damage is detectable after sunbed exposure, which is comparable to DNA damage induced by exposure to nat- ural sunlight; this is chiefly caused by the UVB fraction present in the output of most sunbeds [37,38]. Thus, at present, the available scientific data hardly support the idea that an artificially acquired tan would be safer than a tan acquired through sun exposure. Acquisition of a tan with sunbed use would achieve the maximum protective effect through a combination of pigmentation and skin thickening Recent data show that acquisition of a prevacation tan offers only little pro- tection against UV-induced DNA damage [39], and the moderate skin thick- ening induced by sunbed use would afford even less photoprotection than tanning [40]. Also, many uncertainties persist as to the role of melanin, and of the induction of melanin synthesis in skin carcinogenesis [41,42]. A prevacation tan confers protection against sunburn and other deleterious effects of the sun This argument is a corollary of the former one. Surveys in various fair-skinned communities show that between 25 and 50% of sunbed users report that they want to ‘prepare the skin for the holidays’. Because a prevacation tan offers some protection against sun-induced erythema, a prevacation tan may induce hazardous sun exposure behaviour, such as the promotion of prolonged sun exposure. Hence, the risk of melanoma eventually associated with indoor tan- ning would include not only the exposure to UV radiation emitted by tanning devices, but also the possibility of increased sun exposure at the start of the holiday [39]. Regulations A number of reports from various scientific domains have triggered reactions intended to discourage use of sunbeds [43–46]. Norms for cosmetic use of UV- emitting devices have been published by official organizations [47–50]. Since 1990, several countries (e.g. Sweden, UK, France, Belgium, USA, Canada) have issued specific regulations for sunbed installation, with indications of which of the different types of tanning device can be made available to the gen- eral public, commercial facilities and health professionals. These regulations also include a series of recommendations covering a broad ranges of issues, such as how tanning units must be operated and the information operators ARE SUNBEDS DANGEROUS? 25 must deliver to consumers. There is advice about what warning messages should be visible in the room where the sunbed is installed, the protection of eyes, the danger of taking photosensitizing medications or lotions, and many other aspects. In some countries (e.g. UK and the Netherlands) lists of recommendations exist, formulated by, or in association with the sunbed industry. In the present state of controversy, only those regulations or recommendations originating from bodies working in total independence from commercial interests should be considered. An important objective of these regulations is the requirement for better information for consumers. The impact of these regulations on potential health hazards associated with sunbed use is, however, difficult to estimate. On the positive side, these regulations are likely to protect consumers against the most dangerous UV devices. However, enforcement of regulations re- mains a challenge [8–17] and surveys repeatedly show the ignorance of both sunbed users and tanning facility operators of health hazards associated with indoor tanning. Existing regulations do not apply to private use of sunbeds. Furthermore, they rarely reflect the body of knowledge available on the association between UV exposure and skin cancers or other UV-induced lesions, such as premature skin ageing. In that respect, most existing regulations could simply result in the provision of a false sense of security to both consumers and tanning parlour operators, and thus encourage indoor tanning. Conclusions Despite regulations and recommendations, the bottom line is that each time an individual desires to acquire a tan, or to feel a sensation of well-being, either through sunbathing or through sunbed use, there is exposure to biologically effective, potentially carcinogenic doses of UV. Hence, from a strict point of view — exposure to a hazardous health agent — the sunbed market remains largely unregulated. If the latency period hypothesis is well grounded, the accumulating data from daily dermatological practice, and laboratory or epidemiological re- search provide good reasons to believe that the indoor tanning fashion may represent a time-bomb. Given the great number of subjects currently using sunbeds, even a moderate increase in risk may contribute to a significant extra number of melanoma patients in the next decades. It is unlikely that public health control of indoor tanning will effectively take place in the absence of visible life-threatening conditions attributable to that fashion. With time, the melanoma risk eventually conveyed by indoor tanning will become more apparent, mainly in the northern areas of America 26 CHAPTER 2 and Europe. New epidemiological studies are needed to monitor the impact of sunbed use on the occurrence of skin and eye cancers, and to establish whether the latency period hypothesis is valid or not. In the meantime, health prevention programmes should discourage sunbed use. Prevention messages should be targeted to adolescents and young adults, with the main objective of bringing correct information on health hazards possibly associated with indoor tanning, and to combat the numerous unverified beliefs accompanying the promotion of exposure to artificial sources of UV radiation. References ARE SUNBEDS DANGEROUS? 27 1 International Agency for Research on Cancer (IARC). Solar and ultraviolet radiation. IARC Monogr Eval Carcinog Risks Hum 1992; 55: 217–28. 2 Rivers JK, Norris PG, Murphy GM, et al. UVA sunbeds: tanning, photoprotection, acute adverse effects and immunological changes. Br J Dermatol 1989; 120: 767–77. 3Wright AL, Hart GC, Kernohan E, Twentyman G. Survey of the variation in ultraviolet outputs from ultraviolet A sunbeds in Bradford. Photodermatol Photoimmunol Photomed 1996; 12: 12–16. 4 McGintley J, Martin CJ, MacKie RM. Sunbeds in current use in Scotland: a survey of their output and patterns of use. Br J Dermatol 1998; 139: 428–38. 5Wright AL, Hart GC, Kernohan EE. Dangers of sunbeds are greater in the commercial sector. Br Med J 1997; 314: 1280–1. 6 Autier P, Doré JF, Lejeune F, et al. Cutaneous malignant melanoma and exposure to sunlamps or sunbeds: an EORTC multicenter case–control study in Belgium, France and Germany. Int J Cancer 1994; 58: 809–13. 7 Autier P, Joarlette M, Lejeune F, Lienard D, Andre J, Achten G. Cutaneous malignant melanoma and exposure to sunlamps and sunbeds: a descriptive study in Belgium. Melanoma Res 1991; 1: 69–74. 8 Oliphant JA, Forster JL, McBride CM. The use of commercial tanning facilities by suburban Minnesota adolescents. Am J Public Health 1994; 84: 476–8. 9 Banks BA, Silverman RA, Schwartz RH, Tunnessen WW. Attitudes of teenagers toward sun exposure and sunscreen use. Pediatrics 1992; 89: 40–2. 10 Rhainds M, De Guire L, Claveau J. A population-based survey on the use of artificial tanning devices in the province of Québec. J Am Acad Dermatol 1999; 40: 572–6. 11 Westerdahl J, Olsson H, Masbäck A, et al. Use of sunbeds or sunlamps and malignant melanoma in Southern Sweden. Am J Epidemiol 1994; 140: 691–9. 12 Boldeman C, Beitner H, Jansson B, Nilsson B, Ullen H. Sunbed use in relation to phenotype, erythema, sunscreen use and skin disease: a questionnaire survey among Swedish adolescents. Br J Dermatol 1996; 135: 712–16. 13 Wester U, Boldemann C, Jansson B, Ullén H. Population UV-dose and skin area: do sunbeds rival the sun? Health Phys 1999; 77: 436–40. 14 Chouela E, Pellerano G, Bessone A, Ducard M, Poggio N, Abeldano A. Sunbed use in Buenos Aires. Photodermatol Photoimmunol Photomed 1999; 15: 100–3. 15 Arthey S, Clarke VA. Suntanning and sun protection: a review of the psychological literature. Soc Sci Med 1995; 40: 265–74. 16 Nissen JB, Avrach WW, Hansen ES, Stengaard-Pedersen K, Kragballe K. Increased levels of enkephalin following natural sunlight (combined with salt water bathing at the Dead Sea) and ultraviolet A irradiation. Br J Dermatol 1998; 139: 1012–19. 17 Spencer JM, Amonette RA. Indoor tanning: risks, benefits, and future trends. J Am Acad Dermatol 1995; 33: 288–98. [...]... (1.3–4.1) 2. 2 (1 .2 4.1) 2. 58 (1. 42 4.69) 1.8 (1 .2 2. 7) 1.10 (0.75–1. 62) ≠ ≠ ≠ ≠ - Australia USA Denmark Australia Sweden Spain Spain 1980–81 1981–86 19 82 85 1987–94 1988–00 1989–93 1990–94 507/507 4 52/ 930 474/ 926 50/156 400/640 105/138 116 /23 5 1.1 (0.71–1.60) 0. 62 (0.49–0.83) 1.1 (0.8–1.5) 2. 2 (0.4–11.6) 1.8 (1.1 2. 8) 0 .2 (0.40–0.79) 0.48 (0.34–0.71) Ø ≠ ≠ Ø Ø Europe Austria Sweden 1991– 92 1993–94 1995–97... carcinogenesis J Invest Dermatol Symp Proc 1996; 2: 143–6 22 Euvrard S, Kanitakis J, Pouteil-Noble C, Claudy A, Touraine JL Skin cancers in organ transplant recipients Ann Transplant 1997; 2: 28 – 32 23 Kripke ML, Cox PA, Alas LG, Yarosh DB Pyrimidine dimers in DNA initiate systemic immunosuppression in UVirradiated mice Proc Natl Acad Sci USA 19 92; 89: 7516 20 24 Young AR, Sheehan JM, Chadwick CA, Potten... [ 42] Herzfeld et al [43] Beitner et al [44] Elwoood & Gallagher [45] Holman et al [46] Holly et al [47] Osterlind et al [48] Whiteman et al [49] Westerdahl et al [50] Rodenas et al [51] Espinosa Arranz et al [ 52] Autier et al [53] Wolf et al [54] Westerdal et al [55] Norway USA USA Sweden Canada 1974–75 1974–80 1977–79 1978–83 1979–81 78/131 404/ 521 324 /415 523 /505 369/369 2. 27 (1.3–4.1) 2. 2 (1 .2 4.1)... assessment J Am Acad Dertamol 1998; 38: 89–98 21 Swerdlow AJ, English JSC, MacKie RM et al Fluorescent lights, ultraviolet lamps, and risk of cutaneous melanoma Br Med J 1988; 29 7: 647–50 22 Walter SD, Marrett LD, From L, Hertzman C, Shannon HS, Roy P The association of cutaneous malignant melanoma with the use of sunbeds and sunlamps Am J Epidemiol 1990; 131: 23 2–43 23 Chen Y, Dubrow R, Zheng T, Barnhill... 335 2- 2 7: 1987 + amendement 1: 1989 modified, Brussels, 19 92 49 Food and Drug Administration 1040, Sunlamps products: performance standards — final rule (21 CFR 1040) Federal Register 1985; 50: 36548– 52 50 International Non-Ionizing Radiation Committee of the International Radiation Protection Association Health issues of ultraviolet ‘A’ sunbeds used for cosmetic purpose Health Phys 1991; 61: 28 5–8 Melanoma: ... SUNSCREENS AND MELANOMA 41 Data from 11 of the case–control studies in Table 3.3 have been use for a meta-analysis of 9067 patients, published as an abstract [56] This analysis showed no association between sunscreen use and malignant melanoma with RR of 1.11 (95% CI = 0.37–3. 32) and 1.01 (95% CI = 0.46 2. 28) when using hospital- and population-based studies combined or population-based studies alone,... comprehensive In this 2- year pan-European cross-sectional study of 631 children aged 6–7 years the sunscreen-associated relative risk (RR) for lesions ≥ 2 mm was 1.7 (95% CI = 1.1 2. 6) and 1.5 (95% CI = 0.86 2. 3) on the trunk and head/neck, respectively The authors suggested that this may be caused by increased exposure time in the sun The results of 15 case–control studies on malignant melanomas are summarized... of 300 nm radiation is 0. 025 J/m2 in fair-skinned people However, the median MED at 360 nm is 32 J/m2 [5] This means that 300 nm is 128 0 times more effective per unit physical dose at erythema induction compared with 360 nm An action spectrum is a plot of biological efficacy vs wavelength Very few action spectra 32 CHAPTER 3 (a) (b) Fig 3.1 (a) The emission spectrum of mid-summer (c) solar UVR at 51°N... irradiance and melanoma incidence also lends support for a role for UVA in human melanoma induction [ 12] However, it should be noted that xeroderma pigmentosum patients who specifically lack the ability to repair UVB-induced DNA damage are very prone to both melanoma and non -melanoma skin cancer [13] Overall, it must be said that we do not know the action spectrum for human malignant melanoma Action... can be little doubt that DNA photodamage is important in the pathogenesis of melanoma [13 20 ] UVR-induced suppression of cell-mediated immunity is known to be important in photocarcinogenesis in the mouse [21 ] and a similar role is suspected in humans [22 ] There is also evidence that immunosuppression is mediated via CPD [23 ] This increasing understanding of the mechanistic aspects of skin cancer gives . min 25 20 1.44 0.75 2. 82 ≥ 180 min 39 18 2. 50 1.34–4.80 Test for linear trend in males: P= 0.00 12 Females Never used 22 2 25 6 1.00‡ — < 180 min 39 39 1.17 0.70–1.95 ≥ 180 min 38 27 1. 62 0.91 2. 89 Test. 1988 [29 ]† 9.1 (2. 0–40.6)* 1.9 (0.6–5.6) Ontario, Canada, 1990 [30]† Males 2. 00 (1 .21 –3.34)* 1. 52 (0.56–4 .25 ) Females 1.53 (0.96 2. 46) 1 .24 (0.67 2. 31) Belgium, France, Germany, 1994 [2] ‡ 2. 12 (0.84–5.37). UVR component is sub- Melanoma: Critical Debates Edited by Julia A. Newton Bishop, Martin Gore Copyright © 20 02 Blackwell Science Ltd characterized as UVC (20 0 28 0nm), UVB (28 0–315nm) and UVA