Youth and the Sun: In Search of the Healthy Tan

Youth and the Sun:In Search of a “Healthy Tan”: 

Youth and the Sun: In Search of a “Healthy Tan” Patricia L. Myskowski, M.D. Attending Physician, Dermatology Service Memorial Sloan-Kettering Cancer Center Professor of Dermatology Weill Cornell Medical College

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Photosynthesis Skin Damage Mood elevation Kills pathogens Sight Warmth Skin Cancer Cataracts Vitamin D

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Stratosphere UVC UVA UVB Stratosphere 10-50km Troposphere 0-10km

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Atmosphere (Ozone) UVC UVA UVB

WHAT IS THE DEFINITION OF A “TAN” ?: 

WHAT IS THE DEFINITION OF A “TAN” ? “ More recently-- about 1 million years ago—a tanning response evolved in our hominid ancestors, in which the accumulation of melanin granules in keratinocytes provides physical protection against the DNA-damaging effects of sunlight.” G. Barsh and LD Attardi. A Healthy Tan? N Engl J Med 2007; 356; 2208.

Melanocytes: 

Melanocytes Number of melanocytes is the same in all people. Differences in skin color come from the amount of melanin produced and size of melanosomes where it is stored. Melanocytes react to UV light by converting tyrosine to melanin. Melanin is distributed evenly among basal keratinocytes. Melanin accumulates in the superficial aspect of keratinocytes, shielding nucleus and dermis below from UV rays.

Ultraviolet Effects on Melanogenesis [Tanning]: 

Ultraviolet Effects on Melanogenesis [Tanning] From: Barsh G, Attardi LD. A Healthy Tan? N Engl J Med 2007; 356: 2209, Figure 1: Role of p53 in Tanning

Ultraviolet and Skin: 

Ultraviolet and Skin UVB Burning Rays Mostly summer UVA Tan without burn Year round UVA + UVB = Sun Damage

Skin Type: 

Skin Type Skin Color and Skin Type are determined by the size, shape, density and number of melanosomes. “Type I” (always burn, never tan) “Type II” (burn easily, tan poorly) “Type III” (seldom burn, tan well) “Type IV” (never burn, deep tan) “Type V” (light brown skin) “Type VI” (dark brown skin)

CARCINOGENESIS: UV: 

CARCINOGENESIS: UV Ultraviolet Radiation Tumor suppressor gene inactivation Systemic Immunosuppression (Th2 enhanced) DNA damage (pyrimidine dimers) Langerhans cells damaged Oxygen radicals (cell membrane damage)     

UV induction of DNA damage: 

UV induction of DNA damage Cyclobutane-pyrimidine dimers are the most common DNA photo product formed with UVB; T-T dimer is the most common . T-C (6-4) dimer is the most Common dimer of this type

UV EFFECTS: 

UV EFFECTS

The late 20th century sun and skin cancer connection: 

The late 20th century sun and skin cancer connection Basal Cell Carcinoma Squamous Cell Carcinoma Malignant Melanoma

SKIN CANCER EPIDEMIOLOGY: 

SKIN CANCER EPIDEMIOLOGY MORTALITY INCIDENCE MELANOMA 7400 SCC 2200 BCC 1,050,000 MELANOMA 87,900 SCC 250,000

Incidence of Skin Cancer Increases with Age: 

Incidence of Skin Cancer Increases with Age SEER Cancer Statistics 1994 Incidence of NMSC in the U S, Joseph Scoto et al. NIH Publication # 83-2433, 1983 BCC SCC MM

The Skin Cancer Epidemic: 

The Skin Cancer Epidemic Changing exposure Ozone depletion? Fashion? Recreation?

BCC EPIDEMIOLOGY: 

BCC EPIDEMIOLOGY Most common malignant tumor Most common skin cancer Most common in Caucasians More common in men Increased incidence with age Intermittent sun exposure 80% located on head/neck

SCC EPIDEMIOLOGY: 

SCC EPIDEMIOLOGY Second most common skin cancer 20% of all NMSC Sun-exposed sites Cumulative sun exposure More common in men Incidence increases with age 2200 deaths Fair skin, blue eyes, blonde hair Poor tanning ability UV radiation-chronic

Individual Melanoma Lifetime Risk: USA: 

Individual Melanoma Lifetime Risk: USA 1/75

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U.S Melanoma Incidence/Mortality (per 100,000) Incidence

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Malignant Melanoma : Clinical Findings

Artificial UV Radiation: 

Artificial UV Radiation U. S. indoor tanning industry: 2004: Grossed $5 billion in sales 30 million people use indoor salons Source: J. Am. Acad. Dermatol 2006: 54:433. Tanning bed exposure increases risk of melanoma (Int. J. Dermatol. 2007; 46:1253-7) Indoor tanning and problem behavior (J Am Coll Health 2008; 56:555-561)

Therapeutic Photomedicine: 

Therapeutic Photomedicine Used for: Psoriasis Atopic Dermatitis Polymorphous light eruption and other photodermatoses Scleroderma Urticaria pigmentosa Miscellaneous disorders: Vitiligo Lupus erythematosus CTCL Chronic vesicular dyshidrotic hand eczema Fitzpatrick’s Dermatology in General Medicine, Sixth ed. Dermatologists: in-office treatments with UVB, UVA in lightboxes

SUN PROTECTION: 

SUN PROTECTION Sun avoidance Avoid excessive sun Avoid midday sun Protective clothing Long-sleeved shirt/pants Wide brim hat Sunscreens SPF 30 or higher UVB/UVA protection Apply evenly, reapply

SUNSCREENS: 

SUNSCREENS Protect against UV erythema & inflammation Do not protect against UV immunosuppressive effects Protect against actinic keratoses Protect against SCC

Sun Exposure in Childhood: 

Sun Exposure in Childhood Significant percentage of lifetime exposure Disproportionate biologic effect of exposure Formulation of lifelong attitudes and behaviors Epidemiologic studies: Australia and skin cancer Blistering sunburns before age 15: increased risk of developing malignant melanoma

Conclusions: Youth and the Sun : 

Conclusions: Youth and the Sun Be sensible-and knowledgeable—about the effects of ultraviolet light on the skin Remember— ”a little color” = a little DNA damage Until such time as we can separate the tanning response from the damaging effects of excessive sun exposure— There is no such thing a a healthy tan (except the one you are born with)