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Skin cancer, Ultraviolet radiation and Vitamin D What does it mean for our patients?. Dr Daniel Hewitt MBBS, FACD. The problem of skin cancer Reducing the problem Aetiological factors –Ultraviolet radiation Education to reduce risk factors The vitamin D controversy
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Skin cancer, Ultraviolet radiation and Vitamin DWhat does it mean for our patients? Dr Daniel Hewitt MBBS, FACD
The problem of skin cancer Reducing the problem Aetiological factors –Ultraviolet radiation Education to reduce risk factors The vitamin D controversy Practical recommendations UV index
Skin Cancer in Australia Account for 80% of all newly diagnosed cancers Australia has one of the highest incidence of skin cancer, four times the rates in Canada, the US and the UK. Two in three Australians will be diagnosed with skin cancer by the time they are 70 Each year GPs in Australia have over 1 million patient consultations per year for skin cancer 434,000 people are treated for non-melanoma skin cancers, of which about 450 die.
More than 10,000 people / year are treated for melanoma, of which around 1250 die. Melanoma is the most common cancer in people aged 15-44 years. Melanoma is the third most common cancer in both women and men.
Skin cancer is the most expensive cancer Cost of treatment NMSC $264 million / year melanoma $30 million / year
S Main causative factor = UV radiation Also – scars, chronic inflammation immunosuppression radiation therapy arsenic Risk factors - Long-term ultraviolet exposure Age (>60yo) Male (57%) Pale skin, easily burnt
The response Prevention and early detection 1980’s - Slip, Slop, Slap Sunsmart Campaign
Protect yourself in five ways Rowan’s story Dark side of tanning
Since 1920’s public perception of a tan being healthy has been reinforced by organization with a financial interest - manufacturers of UV lamps - sunscreen lotions eg Coppertone UV claimed to increase resistance to upper respiratory infections improve metabolism treat anaemia improve ‘‘tissue tone’’ and ‘‘skin tone’’ increase mental activity, improve circulation, decrease risk of hepatic cirrhosis, chronic constipation, nephritis, heart disease, eclampsia…
What about Vitamin D? Most vitamin D is obtained via UVR Only a small amount in diet Vitamin D3 or D2 then metabolized into active forms
Many reports have focused on the benefits of vitamin D in preventing disease Osteoporosis Muscle weakness Colon and breast cancer Multiple sclerosis Diabetes ? Melanoma ? Prostate cancer ? Ovarian cancer
Epidemiological studies in US Breast cancer 9/13 reported a favourable association of vitamin D markers or sunlight with cancer risk Colon cancer or adenomatous polyps 20/30 found a statistically significant benefit of vitamin D or sunlight exposure on cancer risk
Vitamin D and cancer Vitamin D and its metabolites inhibit tumour angiogenesis stimulate adherence of cells enhancing intercellular communication through gap junctions and thereby strengthen the inhibition of proliferation that results from tight physical contact with adjacent cells within a tissue
Reported widely in the media “The epidemic of Vitamin D deficiency” – undermined previous campaigns Teenagers in Queensland using inadequate sun protection
Who is at risk of Vitamin D deficiency? • naturally dark skinned people who need more UV exposure to produce adequate levels of vitamin D • people who cover their skin for religious or cultural reasons • the elderly and people who are housebound or in institutional care • babies and infants of vitamin D deficient mothers, especially if the babies are breastfed • patients with osteoporosis People in these groups should consult their doctor for advice on whether or not they need to take a vitamin D supplement.
Exposure of 10% of body area to 1 MED is equivalent to ingestion 1000 IU of vitamin D Oral supplementation is relatively inefficient but should be considered for at risk patients 1000 IU / day 50000 IU / month
What do we tell patients? Very difficult to give one recommendation to the whole of Australia which spans 35 degrees of latitude
UV index Describing the solar UV radiation intensity at any particular time. Each point on the Index scale is equivalent to 25 milliWatts/square metre of UV radiation. On Bureau of Meterology website It is presented as a map of Australia as well as graphs and text tables for over 200 cities and towns. The graphs and text UV Index forecasts include the SunSmart UV Alert. Replicated in media
Guidelines for our patients Summary of the risks and benefits of sun exposure position statement Australian and New Zealand Bone and Mineral Society, Osteoporosis Australia, Australasian College of Dermatologists and The Cancer Council Australia. Sun protection is usually required if the ultraviolet (UV) index is 3 and above (and people are advised to check the forecast UV index in their local area). Most people achieve adequate vitamin D levels through incidental sun exposure, but people living in the southern Australian states in winter may need 2–3 hours of sun exposure on the hands, arms and face each week. Some people are at high risk of developing skin cancer and need more rigorous sun protection than the general population. Some subgroups of the population, such as the frail and elderly, and people who cover most of their body with clothing for cultural or religious reasons, may need to consult their doctor to have their vitamin D status investigated and supplemented if necessary.
References Holick MF. Sunlight “D”ilemma: risk of skin cancer or bone disease and muscle weakness. The Lancet, 2001, 357, 4-6. Garland CF. Sun avoidance will increase incidence of cancers overall. BMJ, 2003, 327, 1228. Osborne JE, Hutchinson PE. Vitamin D and systemic cancer: is this relevant to malignant melanoma? BJD, 2002, 147, 197–213. Garlan CF, Garland FC et al. The Role of Vitamin D in Cancer Prevention. AmericanJournal of Public Health, 2006, 96, 252-61. Wolpowitz D, Gilchrest BA. The vitamin D questions: How much do you need and how should you get it? JAAD, 2006, 54, 301-17. Janda M, Kimlin MG, et al. Sun protection messages, vitamin D and skin cancer: out of the frying pan and into the fire? MJA, 2007, 186, 52-4. Weinstock MA, Moses AM. Skin cancer meets vitamin D: The way forward for dermatology and public health. JAAD, 2009, 61, 720-4. Australian Government Bureau of Meterology www.bom.gov.au Australian Radiation Protection and Nuclear Safety Agency http://www.arpansa.gov.au/uvindex/realtime/index.cfm Cancer Council Australia http://www.cancer.org.au/documents/Risks_Benefits_Sun_Exposure_MAR05.pdf