Sunscreen and Melanoma

SUNSCREEN AND MELANOMA “IS OUR PREVENTION MESSAGE CORRECT?” 2012

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Sunscreen and MelanomaIs Our Prevention Message Correct?Margaret B. Planta, MDPosted: 12/25/2011; J Am Board Fam Med. 2011;24(6):735-739. © 2011 American Board of Family Medicine

Abstract and Introduction

Abstract

Many primary care providers advise patients to use sunscreen as a means to reduce their risk for skin cancer, especially cutaneous malignant melanoma (CMM). Despite the availability and promotion of sunscreen for decades, the incidence of CMM continues to increase in the U.S. at a rate of 3% per year. There currently is little evidence that sunscreens are protective against CMM. A number of studies suggest that the use of sunscreen does not significantly decrease the risk CMM, and may actually increase the risk of CMM and sunburns. This paper discusses current information regarding the relationship between sunscreen use and CMM, and how providers may need to alter their advice regarding sunscreen use for CMM prevention.

Introduction

For years, primary care providers have advised patients to use sunscreen as a means to reduce their risk of skin cancer, especially cutaneous malignant melanoma (CMM). However, between 1973 and 2003, the incidence of CMM increased by 81% and continues to increase at a rate of 3% per year.[1] According to a 2006 US Environmental Protection Agency publication, "there is no evidence that sunscreens protect you from malignant melanoma."[2] A number of studies suggest that the use of sunscreen either does not significantly decrease the risk or may actually increase the risk of CMM.[3–7] Other studies indicate that sunscreen users, when compared with nonusers, may actually be more likely to develop sunburns, thereby possibly increasing their risk of CMM.[7–9] These studies, as well as the continued increase in rates of CMM, call into question whether our current advice regarding sunscreen use is truly beneficial in preventing CMM or if it may actually be detrimental in the fight against CMM.

1 JURNAL READING ILMU PENYAKIT KULIT DAN KELAMIN – LAILI FATHIYAH 1102006149


How Sunscreen Can Contribute to Increased Melanoma Incidence

Ultraviolet (UV) radiation is a known carcinogen.[10] Both UVA and UVB radiation is emitted by the sun, but because UVB was thought to be the primary causative agent of all skin cancers by direct damage to DNA, initial sunscreens were developed that blocked UVB with little or no protective effects against UVA. The sun protection factor (SPF) label on sunscreen relates to protection against UVB radiation and is not at all related to UVA radiation protection.

Recent studies suggest that UVA radiation plays a role in the development of melanoma, not necessarily through direct DNA damage but through oxidative stress, free radical generation, and the degradation of vitamin D.[11–16] The higher ratio of UVA to UVB given off by sunlamps and tanning beds compared with natural sunlight may contribute to greater melanoma risk among tanning bed users.[11,17–19] Sunscreens that contain benzophenones (such as oxybenzone and sulisobenzone), avobenzone (Parsol 1789), ecamsule (Mexoryl, La Roche-Posay, France), titanium dioxide, or zinc oxide may provide some UVA protection. However, in one in vitro analysis of sunscreen ingredients used to block UVA, the most effective filter, titanium dioxide, blocked only 25% of UVA radiation.[20]

Though a number of studies show that the use of sunscreen can reduce the risk of squamous cell carcinoma, sunscreen use was found to be less effective in reducing the risk of basal cell carcinoma.[21–23] Furthermore, there is no convincing evidence that sunscreen use protects against CMM. Several studies show either no difference in CMM rates between sunscreen users and nonusers or a slight increased risk of CMM in sunscreen users among certain populations.[3–7]

Although there is convincing evidence that nonmelanoma skin cancer is related to cumulative sun exposure,[6,23] there is less evidence of that association with CMM. If CMM were related to cumulative sun exposure, one would expect that outdoor workers would have a greater incidence of CMM than indoor workers. However, that is not the case.[6] The incidence of CMM is actually increasing among indoor workers who receive three to nine times less solar UV radiation than outdoor workers.[16]Furthermore, there is a higher incidence of CMM among whites living in northern states such Delaware, Vermont, and New Hampshire (>30 per 100,000), which enjoy less year-round sunlight and UV radiation than southern states such as Texas, Florida, Arizona, and New Mexico (<25 per 100,000).[24] In California, whites living in San Francisco had a CMM incidence of 30.5 per 100,000, whereas those living in Los Angeles had an incidence of 24.9 per 100,000.[24]

There are a few studies that suggest that chronic, low-grade exposure to sunlight may be protective against CMM. In one Austrian study, those with chronic sun exposure without sunburn had a reduced incidence of CMM compared with those with recreational sun exposure.[4] In Germany, outdoor activities during childhood, in the absence of sunburn, were associated with a lower risk of melanoma.[25] Chronic, repeated sun exposure may allow the skin to accommodate to UV radiation by increasing melanin production, thereby reducing the risk of sunburn.[26] An English study published in 2011 showed that regular weekend sun exposure had a



protective effect against CMM, and the researchers postulated that this may be mediated by photo-adaptation or higher vitamin D levels.[27]

Another point suggested by these studies is that sunburns, and not cumulative sun exposure, lead to increased risk for CMM. In an analysis of 15 case-control studies, Chang et al[28] concluded that sunburn is a strong predictor of melanoma at all latitudes, whereas cumulative sun exposure affects melanoma risk only at low latitudes, defined as between 34° north/south and 20° north/south. Most of the United States lies north of 34° latitude. If cumulative sun exposure does not affect melanoma risk at countries at higher latitudes, such as the United States, and if chronic, low-grade exposure to sunlight is protective against CMM in these countries, then perhaps our emphasis on counseling patients in the United States should focus on sunburn, not sunlight, avoidance.

When used improperly, sunscreen can potentially increase the risk for CMM by conferring a false sense of protection against sunburn. This false sense of protection can lead to more time spent in the sun, paradoxically causing a greater incidence of sunburns. In two European studies, sunbathers who used SPF 30 sunscreen sunbathed 19% to 25% longer than those using SPF 10.[8] In a Danish study, 66% of sunburned people had used sunscreen to prolong time spent in the sun.[9] In addition, those most likely to use sunscreen where those with the skin type most likely to burn.[7] A number of studies have shown a correlation between the use of sunscreen and increased incidence of sunburn.[7,9]

With the advent of sunscreens of SPF 50 and higher, this false sense of security may be amplified, and sun exposure time may be prolonged. Because of this, the incidence of sunburns may be increased in the population most at risk for sunburns, thereby continuing the upward trend of melanoma incidence. This false sense of security may be experienced not only by sunbathers, but by parents of small children as well. In a Swedish study, children aged 2 to 7 whose parents had applied sunscreen on them were more likely to experience sunburn than those who received little or no sunscreen.[7] Sunburns during childhood significantly increase the risk for CMM more than sunburns later in life.[7] We may need to rethink how we educate our patients about the proper use of sunscreen on themselves and on their children.

What About the Australian Study?

Most of the studies indicating no protective benefit against or even increased risk of CMM with sunscreen use were performed using sunscreen that blocked only UVB radiation. Broad-spectrum UVA/UVB sunscreens now available may provide more protection against sunburns and subsequent melanoma. In a randomized, controlled, prospective study conducted by Green et al[29] in Australia, consistent daily application of both UVA and UVB-filtering broad-spectrum sunscreen resulted in a decreased incidence of melanoma compared with control. What should be noted about the study is that the control group was allowed to use sunscreen as well, but was not guided as to type of sunscreen used or the frequency of application. Therefore, in this study, only daily, consistent use of broad-spectrum sunscreen, but not intermittent use of sunscreen, was



associated with decreased risk of CMM. There is still no evidence that the intermittent use of sunscreen, as is more commonly practiced among the US population, reduces the incidence of CMM.

Furthermore, the financial feasibility of this intervention needs to be considered. Daily, rather than intermittent, use of sunscreen incurs a higher cost. A cost-benefit analysis of this intervention is yet to be done. In the Green et al[29] study, unlimited, free, broad-spectrum sunscreen was supplied to the intervention group but not the control group. Part of the reason the control group applied sunscreen less frequently may possibly have to do with cost. The cost to the individual for this intervention may hamper compliance.

Though those living in Australia may be highly motivated to reduce their skin cancer risk, compliance with this regimen may be problematic in the US population, who currently exhibits poor sun-protective behavior, even those at increased risk.[30,31]Applying this intervention in the United States would require convincing populations in higher risk northern states[24] to continue to apply sunscreen daily in the middle of winter.

Finally, the Green et al[29] study was performed in the low-latitude township of Nambour, situated at 26° south latitude, where cumulative sun exposure affects melanoma risk.[28] The United States is not a low-latitude country, and studies do not indicate that cumulative sun exposure affects melanoma risk outside of low latitudes.[28] So, it is unclear whether this protective benefit of daily sunscreen use is applicable to the US population.

Because of ethical issues, a randomized, controlled, prospective study examining intermittent sunscreen use versus no use will likely never be done. But future case-control and cohort studies may show benefit with the newer broad-spectrum sunscreens now available. Until those studies are conducted, the protective benefits of sunscreen use against CMM in the US population remain unproven and controversial.

In July 2011, the Journal of the American Medical Association published a commentary by Robinson and Bigby,[32] who suggested that the data from Green et al's[29] study supports advocating regular sunscreen use in high-risk individuals for the primary prevention of CMM. The authors did not discuss any measures to overcome the limitations of the Green study as discussed above. Also, although the authors offered good advice about counseling high-risk individuals on the proper use of sunscreen, the authors did not mention specifically counseling against sunburn, which is a strong predictor of melanoma risk.[28] Sunscreen, when used properly, can be highly effective in reducing the risk of sunburn; however, the lack of specifically counseling against sunburn, may possibly lead to the misuse of sunscreen and may increase the risk of sunburn and resultant CMM.[7–9]

Discussion



Based on currently available information, the "harm" related to sunscreen use is probably not intrinsic to sunscreens;[33] it is more likely related to the improper use of sunscreen, resulting in more sunburns.[7–9] Primary care providers who encourage the use of sunscreen should also instruct patients about the proper use of sunscreen to avoid sunburns. Primary care providers need to alter their patients' current perception that using sunscreen allows them unrestricted latitude in the amount of time spent in the sun. If we counsel patients against the abuse of sunscreen and alter their behavior patterns with respect to sunburns, it is possible that future sunscreen studies may confirm the benefit of sunscreen use against CMM. Because there is still insufficient evidence that shows that the use of sunscreen reduces CMM risk in the US population, for now we should not be advising patients that using sunscreen will protect them from CMM. Instead, we should advise them that the proper use of sunscreen is one way to prevent sunburn and that the best way to reduce their risk of CMM, with respect to natural solar radiation, is to prevent sunburn. With that in mind, some suggested points for counseling include:

1. Sunscreen should not be used to prolong the amount of time spent in the sun. When used for that purpose, there is a greater risk of becoming sunburned.[8,9]

2. If the skin becomes uncomfortable or red at any time during solar radiation exposure, whether intentional or unintentional, with or without sunscreen, and regardless of length of time spent in the sun, the patient should cover up or seek shade immediately. Simply reapplying sunscreen and failing to seek shelter may increase the risk of sunburn and subsequent CMM.[8,9,34]

3. Clothing, hats, and sunglasses provide protection against the damaging effects of solar UV radiation. Some studies suggest a negative correlation between clothing and sunburn.[9,35] However, not all textiles provide equal UV protection.[35,36] Therefore, a combination of clothing and sunscreen would probably provide the best protection against solar UV radiation. Patients should be advised that sunscreen should be used as an adjunct to, not a substitute for, clothing and hats.

4. Because UVA radiation may also play a role in the formation of skin cancer,[11–15] patients should use sunscreen that provides protection against both UVA and UVB radiation.

5. Those at high risk of CMM may possibly benefit from consistent, daily use of broad-spectrum sunscreen.[29,32]

References

1. Ries LAG, Harkins D, Krapcho M, et al (eds). SEER cancer statistics review, 1975–2003. Available at: http://seer.cancer.gov/csr/1975_2003/. Accessed 24 September 2011.



2. United States Environmental Protection Agency. Sunscreen: The Burning Facts. Available at: http://www.epa.gov/sunwise/doc/sunscreen.pdf. Accessed 24 September 2011.

3. Huncharek M, Kupelnick B. Use of topical sunscreens and the risk of malignant melanoma: a metaanalysis of 9067 patients from 11 case-control studies. Am J Public Health 2002;92(7):1173–7.

4. Wolf P, Quehenberger F, Müllegger R, Stranz B, Kerl H. Phenotypic markers, sunlight-related factors and sunscreen use in patients with cutaneous melanoma: an Austrian case-control study. Melanoma Res 1998;8(4):370–8.

5. Gorham ED, Mohr SB, Garland CF, Chaplin G, Garland FC. Do sunscreens increase risk of melanoma in populations residing at higher latitudes? Ann Epidemiol 2007;17(12):956–63.

6. Radespiel-Tröger M, Meyer M, Pfahlberg A, Lausen B, Uter W, Gefeller O. Outdoor work and skin cancer incidence: a registry-based study in Bavaria. Int Arch Occup Environ Health 2009;82(3):357– 63.

7. Rodvall YE, Wahlgren CF, Ullén HT, Wiklund KE. Factors related to being sunburnt in 7-year-old children in Sweden. Eur J Cancer 2010;46(3):566 –72.

8. Autier P, Boniol M, Doré JF. Sunscreen use and increased duration of intentional sun exposure: still a burning issue. Int J Cancer 2007;121(1):1–5.

9. Køster B, Thorgaard C, Philip A, Clemmensen IH. Prevalence of sunburn and sun-related behaviour in the Danish population: a cross-sectional study. Scand J Public Health 2010;38(5):548 –52.

10. U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program. Report on carcinogens, 12th edition. Available at: http://ntp.niehs.nih.gov/ntp/roc/twelfth/roc12.pdf. Accessed 24 September 2011.

11. Garland CF, Garland FC, Gorham ED. Epidemiologic evidence for different roles of ultraviolet A and B radiation in melanoma mortality rates. Ann Epidemiol 2003;13(6):395– 404.

12. Berking C. [The role of ultraviolet irradiation in malignant melanoma.] Hautarzt 2005;56(7):687–96, quiz 697.

13. Situm M, Buljan M, Bulić SO, Simić D. The mechanisms of UV radiation in the development of malignant melanoma. Coll Antropol 2007;31(Suppl 1): 13–6.

14. Garland CF, Garland FC, Gorham ED. Rising trends in melanoma. An hypothesis concerning sunscreen effectiveness. Ann Epidemiol 2007;3(1): 103–10.

15. Wischermann K, Popp S, Moshir S, et al. UVA radiation causes DNA strand breaks, chromosomal aberrations and tumorigenic transformation in HaCaT skin keratinocytes. Oncogene 2008;17; 27(31):4269–80.

16. Godar DE, Landry RJ, Lucas AD. Increased UVA exposures and decreased cutaneous Vitamin D(3) levels may be responsible for the increasing incidence of melanoma. Med Hypotheses 2009;72(4): 434–43.



17. Lazovich D, Vogel RI, Berwick M, Weinstock MA, Anderson KE, Warshaw EM. Indoor tanning and risk of melanoma: a case-control study in a highly exposed population. Cancer Epidemiol Biomarkers Prev 2010;19(6):1557– 68.

18. International Agency for Research on Cancer Working Group on artificial ultraviolet (UV) light and skin cancer. The association of use of sunbeds with cutaneous malignant melanoma and other skin cancers: a systematic review. Int J Cancer 2007;120(5): 1116–22.

19. Gerber B, Mathys P, Moser M, Bressoud D, Braun- Fahrländer C. Ultraviolet emission spectra of sunbeds. Photochem Photobiol 2002;76(6):664–8.

20. Couteau C, El-Boury S, Paparis E, Sébille-Rivain V, Coiffard LJ. In vitro UV-A protection factor (PFUVA) of organic and inorganic sunscreens. Pharm Dev Technol 2009;14(4):369 –72.

21. Green A, Williams G, Neale R, et al. Daily sunscreen application and betacarotene supplementation in revention of basal-cell and squamous-cell carcinomas of the skin: a randomised controlled trial. Lancet 1999;354(9180):723–9.

22. Ulrich C, Jürgensen JS, Degen A, et al. Prevention of non-melanoma skin cancer in organ transplant patients by regular use of a sunscreen: a 24 months, prospective, case-control study. Br J Dermatol 2009; 161(Suppl 3):78–84.

23. Kütting B, Drexler H. UV-induced skin cancer at workplace and evidence-based prevention. Int Arch Occup Environ Health 2010;83:843–54.

24. Centers for Disease Control and Prevention, National Program of Cancer Registries. United States Cancer Statistics. 2003–2007 Melanomas of the skin, United States. Available at: http://apps.nccd.cdc.gov/uscs/cancersbystateandregion.aspx. Accessed 24 September 2011.

25. Kaskel P, Sander S, Kron M, Kind P, Peter RU, Krähn G. Outdoor activities in childhood: a protective factor for cutaneous melanoma? Results of a case-control study in 271 matched pairs. Br J Dermatol 2001;145(4):602–9.

26. Moan J, Dahlback A, Setlow RB. Epidemiological support for an hypothesis for melanoma induction indicating a role for UVA radiation. Photochem Photobiol 1999;70(2):243–7.

27. Newton-Bishop JA, Chang YM, Elliott F, et al. Relationship between sun exposure and melanoma risk for tumours in different body sites in a large casecontrol study in a temperate climate. Eur J Cancer 2011;47(5):732– 41.

28. Chang YM, Barrett JH, Bishop DT, et al. Sun exposure and melanoma risk at different latitudes: a pooled analysis of 5700 cases and 7216 controls. Int J Epidemiol 2009;38(3):814 –30.

29. Green AC, Williams GM, Logan V, Strutton GM. Reduced melanoma after regular sunscreen use: randomized trial follow-up. J Clin Oncol 2011;29(3): 257–63.

30. Spradlin K, Bass M, Hyman W, Keathley R. Skin cancer: knowledge, behaviors, and attitudes of college students. South Med J 2010;103(10):999 –1003.



31. Geller AC, Brooks DR, Colditz GA, Koh HK, Frazier AL. Sun protection practices among offspring of women with personal or family history of skin cancer. Pediatrics 2006;117(4):e688 –94.

32. Robinson JK, Bigby M. Prevention of melanoma with regular sunscreen use. JAMA 2011;306(3): 302–3.

33. Burnett ME, Wang SQ. Current sunscreen controversies: a critical review. Photodermatol Photoimmunol Photomed 2011;27(2):58–67.

34. Bränström R, Kasparian NA, Chang YM, et al. Predictors of sun protection behaviors and severe sunburn in an international online study. Cancer Epidemiol Biomarkers Prev 2010;19(9):2199 –210.

35. Gambichler T, Altmeyer P, Hoffmann K. Role of clothes in sun protection. Recent Results Cancer Res 2002;160:15–25.

36. Wolska A, Owczarek G, Bartkowiak G. UV protective textile clothing for workers exposed to natural and artificial UV radiation. Conf Proc IEEE Eng Med Biol Soc 2010;2010:6260–3.

Funding none.

Conflict of interest none declared.

J Am Board Fam Med. 2011;24(6):735-739. © 2011 American Board of Family Medicine



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Tabir Surya dan MelanomaApakah pesan pencegahan kita sudah benar?Margaret B. Planta, MDPosted: 12/25/2011; J Am Board Fam Med. 2011;24(6):735-739. © 2011 American Board of Family Medicine

Abstrak dan Pendahuluan

Abstrak

Banyak penyedia layanan kesehatan primer menyarankan pasien untuk menggunakan tabir surya sebagai alat untuk mengurangi risiko untuk kanker kulit, terutama melanoma maligna(CMM). Meskipun ketersediaan dan promosi tabir surya selama beberapa dekade, kejadian CMM terus meningkat di AS pada tingkat 3% per tahun. Pada saat ini terdapat sedikit bukti bahwa tabir surya yang melindungi terhadap CMM. Sejumlah studi menunjukkan bahwa penggunaan tabir surya tidak secara signifikan menurunkan risiko CMM, dan benar-benar dapat meningkatkan risiko CMM dan terbakar matahari. Tulisan ini membahas informasi terkini mengenai hubungan antara penggunaan tabir surya dan CMM, dan bagaimana penyedia mungkin perlu mengubah saran mereka mengenai penggunaan tabir surya untuk pencegahan CMM.

Pengenalan

Selama bertahun-tahun, penyedia layanan kesehatan primer telah menyarankan pasien untuk menggunakan tabir surya sebagai alat untuk mengurangi risiko kanker kulit, terutama melanoma maligna (CMM). Namun, antara tahun 1973 dan 2003, kejadian CMM meningkat sebesar 81% dan terus meningkat pada tingkat 3% per tahun [1]. Menurut Perlindungan Lingkungan US Agency publikasi tahun 2006, "Tidak ada bukti bahwa tabir surya melindungi Anda dari melanoma ganas " [2]. Sejumlah studi menunjukkan bahwa penggunaan tabir surya baik tidak signifikan mengurangi risiko atau benar-benar dapat meningkatkan risiko dari CMM [3-

7]. Penelitian lain menunjukkan bahwa pengguna tabir surya, bila dibandingkan dengan bukan pengguna , sebenarnya mungkin lebih cenderung untuk terbakar matahari, sehingga mungkin meningkatkan risiko CMM [7-8]. Studi-studi ini, serta terus bertambahnya tingkat CMM, menimbulkan pertanyaan apakah saran kami saat ini mengenai penggunaan tabir surya benar-benar bermanfaat dalam mencegah CMM atau itu benar-benar dapat merugikan dalam memerangi CMM.



Bagaimana kontribusi dari tabir surya sehingga dapat meningkatkan insiden Melanoma?

Ultraviolet (UV) adalah karsinogen [10]. Baik radiasi UVA dan UVB yang dipancarkan oleh matahari, tetapi karena UVB dianggap agen penyebab utama dari semua kanker kulit dengan kerusakan langsung pada DNA, tabir surya awal dikembangkan yang diblokir adalah UVB dengan efek protektif sedikit atau tidak terhadap UVA. Perlindungan matahari Faktor (SPF) label pada tabir surya berkaitan dengan perlindungan terhadap radiasi UVB dan sama sekali tidak berhubungan dengan proteksi radiasi UVA.

Penelitian terbaru menunjukkan bahwa radiasi UVA berperan dalam perkembangan melanoma, tidak harus melalui kerusakan DNA langsung tetapi melalui stres oksidatif, generasi radikal bebas, dan degradasi vitamin D. [11-16] Rasio yang lebih tinggi dari UVA UVB disebabkan oleh sunlamps dan tanning bed dibandingkan dengan sinar matahari alami , risiko melanoma lebih besar ditemui di antara pengguna tanned bed. [11,17-19] Tabir surya yang mengandung benzofenon (seperti oksibenzon dan sulisobenzone), avobenzone (Parsol 1789), ecamsule (Mexoryl, La Roche-Posay, Prancis), titanium dioksida, seng oksida atau mungkin dapat memberikan perlindungan UVA. Namun, dalam satu dalam analisis in vitro bahan tabir surya dapat digunakan untuk memblokir UVA, filter yang paling efektif, titanium dioksida, memblokir hanya 25% dari radiasi UVA [20].

Meskipun sejumlah studi menunjukkan bahwa penggunaan tabir surya dapat mengurangi risiko karsinoma sel skuamosa, penggunaan tabir surya ditemukan menjadi kurang efektif dalam mengurangi risiko karsinoma sel basal [21-23] Selanjutnya, tidak ada bukti yang meyakinkan bahwa penggunaan tabir surya melindungi terhadap terjadinya CMM. Beberapa penelitian menunjukkan tidak ada perbedaan dalam tingkat terjadinya resiko CMM antara pengguna dan bukan pengguna tabir surya atau risiko meningkat sedikit dari terjadinya CMM dalam pengguna tabir surya antara populasi tertentu. [3-7]

Meskipun ada bukti yang meyakinkan bahwa kanker kulit nonmelanoma berhubungan dengan paparan kumulatif sinar matahari [6,23] ada bukti sedikit yang berhubungan dengan CMM. Jika CMM berhubungan dengan paparan kumulatif sinar matahari, orang akan berharap bahwa pekerja luar ruangan akan memiliki insiden lebih besar dari CMM daripada pekerja dalam ruangan. Namun, itu tidak terjadi. [6] Insiden CMM sebenarnya meningkat di kalangan pekerja dalam ruangan yang menerima tiga sampai sembilan kali lebih sedikit radiasi UV matahari daripada pekerja luar ruangan [16] Selain itu, ada insiden yang lebih tinggi dari CMM di antara kulit putih yang tingal di Negara bagian utara seperti Delaware, Vermont, dan New Hampshire (> 30 per 100.000), yang menikmati sinar matahari kurang sepanjang tahun dan radiasi UV dari negara-negara selatan seperti Texas, Florida, Arizona, dan New Mexico (<25 per 100.000). [ 24] Di California, kulit putih yang tinggal di San Francisco memiliki insiden CMM dari 30,5 per 100.000, sedangkan mereka yang tinggal di Los Angeles memiliki kejadian 24,9 per 100.000. [24]

Ada beberapa studi yang menunjukkan bahwa paparan sinar matahari tingkat rendah dapat melindungi terhadap CMM. Dalam satu studi Austria, mereka dengan paparan sinar



matahari tanpa terbakar sinar matahari kronis memiliki insiden mengurangi CMM dibandingkan dengan mereka dengan paparan sinar matahari saat rekreasi. [4] Di Jerman, kegiatan di luar ruangan pada waktu kecil, dengan tidak terbakar sinar matahari, dikaitkan dengan rendahnya risiko melanoma [25]. Paparan sinar matahari berulang-kali dapat memungkinkan kulit untuk mengakomodasi terhadap radiasi UV dengan meningkatkan produksi melanin, sehingga mengurangi risiko terbakar sinar matahari. [26] Sebuah studi bahasa Inggris diterbitkan pada tahun 2011 menunjukkan bahwa paparan matahari regular akhir pekan memiliki efek perlindungan terhadap CMM, dan para peneliti menduga bahwa ini mungkin dimediasi oleh foto-adaptasi atau kadar vitamin D yang tinggi. [27]

Hal lain yang diusulkan oleh studi ini adalah terbakar matahari, dan paparan sinar matahari yang tidak kumulatif, menyebabkan peningkatan risiko untuk CMM. Dalam sebuah analisis dari 15 studi kasus kontrol, Chang et al [28] menyimpulkan sengatan matahari yang merupakan prediktor kuat melanoma di semua lintang, sedangkan paparan kumulatif sinar matahari yang mempengaruhi risiko melanoma hanya di lintang rendah, yang didefinisikan sebagai antara 34 ° utara / selatan dan 20 ° utara / selatan. Sebagian besar Amerika Serikat terletak di lintang utara 34 °. Jika paparan kumulatif sinar matahari tidak mempengaruhi risiko melanoma pada negara-negara di lintang yang lebih tinggi, seperti Amerika Serikat, dan jika kronis, tingkat rendah paparan sinar matahari dapat melindungi CMM di negara-negara tersebut, maka mungkin penekanan kami pada konseling pasien di Amerika Serikat harus fokus pada sengatan matahari, bukan sinar matahari, dan penghindaran terhadapnya.

Ketika digunakan secara tidak benar, tabir surya dapat berpotensi meningkatkan risiko CMM dengan pemberian rasa perlindungan aman palsu terhadap sengatan matahari. Rasa perlindungan palsu dapat menyebabkan lebih banyak waktu dihabiskan di bawah sinar matahari, secara paradoks menyebabkan insiden lebih besar dari terbakar matahari. Dalam dua studi di Eropa, studi yang menggunakan tabir surya SPF 30 dijemur 19% sampai 25% lebih lama dibandingkan mereka yang menggunakan SPF 10 [8] Dalam sebuah studi di Denmark, 66% orang terbakar matahari setelah menggunakan tabir surya untuk memperpanjang waktu yang dihabiskan di bawah sinar matahari. [9 ] Selain itu, paling mungkin untuk menggunakan tabir surya mereka di mana mereka yang memiliki jenis kulit yang paling mungkin untuk terbakar [7]

Sejumlah penelitian menunjukkan korelasi antara penggunaan tabir surya dan kejadian peningkatan sengatan matahari. [7,9]

Dengan munculnya tabir surya SPF 50 dan yang lebih tinggi, rasa aman palsu dapat diperkuat, dan waktu pemaparan terhadap matahari mungkin diperpanjang. Karena itu, kejadian terbakar matahari dapat ditingkatkan pada populasi paling berisiko untuk terbakar matahari, sehingga melanjutkan tren kenaikan kejadian melanoma. Rasa aman palsu mungkin dialami tidak hanya oleh berjemur, tapi oleh orang tua anak-anak juga. Dalam sebuah studi di Swedia, anak usia 2 sampai 7 tahun yang orang tuanya telah menerapkan tabir surya pada mereka, lebih mungkin untuk mengalami kulit terbakar daripada mereka yang menerima sedikit atau tidak ada tabir surya. [7] Terbakar matahari selama masa kanak-kanak secara signifikan meningkatkan risiko CMM lebih dari terbakar matahari di kemudian hari [7]. Kita mungkin perlu memikirkan kembali bagaimana kita mendidik pasien tentang penggunaan yang tepat dari tabir surya pada diri mereka sendiri dan anak-anak mereka.



Bagaimana dengan Studi di Australia?

Sebagian besar penelitian menunjukkan tidak ada manfaatnya perlindungan atau bahkan meningkat resiko dari CMM dengan penggunaan tabir surya yang dilakukan dengan menggunakan tabir surya yang menghalangi radiasi UVB saja. Luas spektrum UVA / UVB tabir surya yang sekarang tersedia dapat memberikan perlindungan lebih terhadap terbakar matahari dan melanoma berikutnya. Dalam studi acak, terkontrol, prospektif yang dilakukan oleh Green et al [29] di Australia, aplikasi sehari-hari yang konsisten dari kedua UVA dan UVB-filtering tabir surya spektrum luas menghasilkan penurunan kejadian melanoma dibandingkan dengan kontrol. Yang perlu diperhatikan tentang penelitian ini adalah bahwa kelompok kontrol diperbolehkan untuk menggunakan tabir surya juga, tapi tidak dipandu untuk mengggunakan tabir surya atau frekuensi aplikasi. Oleh karena itu, dalam penelitian ini, yang sehari-hari, penggunaan konsisten dari tabir surya spektrum luas, tetapi tidak menggunakan tabir surya yang intermiten, dikaitkan dengan penurunan risiko CMM. Masih belum ada bukti bahwa penggunaan tabir surya intermiten, seperti yang lebih umum dipraktekkan di kalangan penduduk AS, mengurangi insiden CMM.

Selain itu, kelayakan finansial dari intervensi ini perlu dipertimbangkan. Keseharian, bukan intermiten, penggunaan tabir surya menimbulkan biaya yang lebih tinggi. Sebuah analisis intervensi biaya-manfaat ini belum dilakukan. Dalam kelompok studi Green et al [29], tak terbatas, gratis, tabir surya spektrum luas yang diberikan kepada kelompok intervensi tetapi tidak pada grup kontrol. Sebagian alasan kelompok kontrol lebih jarang diterapkan tabir surya, mungkin dapat memiliki hubungannya dengan biaya. Biaya untuk individu dengan intervensi ini dapat menghambat kepatuhan.

Meskipun mereka yang tinggal di Australia mungkin menjadi sangat termotivasi untuk mengurangi risiko kanker kulit mereka, kepatuhan terhadap rejimen ini mungkin bermasalah dalam populasi AS, yang saat ini menunjukkan miskin terhadap penggunaan pelindung matahari, bahkan mereka pada yang terkena resiko tinggi [30,31]. Menerapkan intervensi ini di Amerika Serikat akan memerlukan keyakinan untuk populasi dengan resiko tinggi di negara bagian utara [24] untuk terus menerapkan penggunaan tabir surya setiap hari di tengah musim dingin.

Akhirnya, penelitian Green et al [29] dilakukan di kota rendah lintang di Nambour, terletak di 26 ° Lintang Selatan, di mana paparan kumulatif sinar matahari mempengaruhi risiko melanoma [28]. Amerika Serikat adalah bukan negara lintang rendah dan studi ini tidak menunjukkan bahwa paparan kumulatif sinar matahari mempengaruhi risiko melanoma lintang rendah. [28] Jadi, tidak jelas apakah ini manfaat perlindungan dari penggunaan tabir surya setiap hari berlaku untuk penduduk AS.

Karena masalah etika, secara acak, terkontrol, penelitian prospektif memeriksa penggunaan tabir surya intermiten dibandingkan kemungkinan penggunaannya yang akan pernah terjadi. Tapi masa depan kasus-kontrol dan studi kohort dapat menunjukkan manfaat dengan tabir surya baru spektrum luas yang sekarang tersedia. Sampai studi dilakukan, manfaat



perlindungan dari penggunaan tabir surya terhadap CMM di penduduk AS tetap belum terbukti dan kontroversial.

Pada bulan Juli 2011, Journal of American Medical Association menerbitkan sebuah komentar oleh Robinson dan Bigby, [32] yang menyarankan bahwa data studi dari Green et al [29]

mendukung advokasi penggunaan tabir surya biasa dalam individu yang berisiko tinggi untuk pencegahan primer CMM. Para penulis tidak membahas langkah-langkah untuk mengatasi keterbatasan dari studi Green seperti dibahas di atas. Meskipun penulis menawarkan nasihat yang baik tentang konseling individu yang berisiko tinggi pada penggunaan yang tepat dari tabir surya, penulis tidak menyebutkan secara khusus konseling terhadap kasus kulit yang terbakar, yang merupakan prediktor kuat risiko melanoma. [28] Tabir surya, bila digunakan dengan benar, bisa sangat efektif dalam mengurangi risiko terbakar sinar matahari. Namun, kurangnya konseling khusus terhadap kulit terbakar, mungkin dapat menyebabkan penyalahgunaan tabir surya dan dapat meningkatkan risiko terbakar sinar matahari dan CMM resultan [7-9]

Diskusi

Berdasarkan informasi yang tersedia saat ini, "bahaya" yang terkait dengan penggunaan tabir surya mungkin bukan intrinsik untuk tabir surya itu sendiri, [33] itu lebih mungkin terkait dengan penggunaan tabir surya yang tidak tepat, sehingga [7-9] penyedia layanan dasar yang mendorong penggunaan tabir surya juga harus menginstruksikan pasien tentang penggunaan yang tepat dari tabir surya untuk menghindari terbakar matahari. Penyedia layanan kesehatan primer perlu mengubah persepsi saat ini terhadap pasien bahwa menggunakan tabir surya memungkinkan mereka terpapar tak terbatas dalam jumlah waktu yang dihabiskan di bawah sinar matahari. Jika kami menasihati pasien terhadap penyalahgunaan tabir surya dan mengubah pola perilaku mereka sehubungan dengan resiko terbakar matahari adalah mungkin bahwa studi tentang tabir surya dapat mengkonfirmasi manfaat dari penggunaan tabir surya terhadap CMM. Karena masih ada cukup bukti yang menunjukkan bahwa penggunaan tabir surya mengurangi risiko CMM dalam penduduk AS, untuk sekarang kita tidak boleh menasehati pasien bahwa menggunakan tabir surya akan melindungi mereka dari CMM. Sebaliknya, kita harus menasihati mereka bahwa penggunaan yang tepat dari tabir surya adalah salah satu cara untuk mencegah kulit terbakar dan bahwa cara terbaik untuk mengurangi risiko dari CMM, sehubungan dengan radiasi matahari alami, adalah untuk mencegah sengatan matahari. Dengan pemikiran, beberapa poin yang disarankan untuk konseling meliputi:

1. Tabir surya tidak boleh digunakan untuk memperpanjang jumlah waktu yang dihabiskan di bawah sinar matahari. Bila digunakan untuk tujuan itu, ada risiko lebih besar untuk menjadi terbakar matahari [8,9].

2. Jika kulit menjadi tidak nyaman atau merah setiap saat saat terpapar radiasi matahari, baik disengaja atau tidak disengaja, dengan atau tanpa tabir surya, dan terlepas dari lamanya waktu yang dihabiskan di bawah sinar matahari, pasien harus menutupi atau mencari keteduhan segera. Cukup mengoleskan tabir surya dan gagal untuk mencari perlindungan dapat meningkatkan risiko terbakar sinar matahari dan CMM berikutnya. [8,9,34]

3. Pakaian, topi, dan kacamata hitam memberikan perlindungan terhadap efek merusak dari



radiasi UV matahari. Beberapa studi menunjukkan korelasi negatif antara pakaian dan sengatan matahari. [9,35] Namun, tidak semua tekstil memberikan perlindungan UV sama. [35,36] Oleh karena itu, kombinasi pakaian dan tabir surya mungkin akan memberikan perlindungan terbaik terhadap radiasi UV matahari. Pasien harus disarankan bahwa tabir surya harus digunakan sebagai tambahan, bukan pengganti, pakaian dan topi.

4. Karena radiasi UVA juga mungkin memainkan peran dalam pembentukan kanker kulit, [11-15]

pasien harus menggunakan tabir surya yang memberikan perlindungan terhadap kedua radiasi UVA dan UVB.

5. Mereka yang berisiko tinggi CMM mungkin dapat mengambil manfaat dari konsisten, penggunaan sehari-hari tabir surya spektrum luas. [29,32]

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Funding none.

Conflict of interest none declared.J Am Board Fam Med. 2011;24(6):735-739. © 2011 American Board of Family Medicine


Sunscreen and Melanoma

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