Hot fun in the summer sun?

Winter is ending and Canadians are coming out of hibernation, ready to play in the sun. While there is nothing wrong with soaking in some sunshine, there are risks,¹ including:

• Premature aging and damage of the skin,
• Weakening of the immune system, making us more susceptible to infections and cancers,
• Damage to eyes, including cataracts, and
• Non-melanoma^* and melanoma skin cancers.

These effects are linked to UV radiation from either direct sunlight or exposure to indoor tanning beds.² UV light can alter the DNA in pigment-producing cells, causing them to multiply and grow out of control. If left untreated it can spread to other parts of the body via the blood stream or lymphatic system.³

Melanoma, the most serious of the skin cancers, can appear anywhere on the body and in many different forms. Melanoma skin cancers start as a change in normal-looking skin (e.g., dark area or an abnormal new mole) and most commonly appear on the back in men and on the legs in women.⁴ It is important to discuss any unusual signs and symptoms with a doctor. For more information, please visit the Canadian Cancer Society or Canadian Dermatology Association websites.

In 2015, there was an estimated 78,300^† people diagnosed with non-melanoma skin cancer.⁵ Of even greater concern, 6,800 people (3,700 men and 3,100 women) were diagnosed with melanoma skin cancer, and incidence rates for melanoma were found to have increased 2.3% and 2.9% per year in men and women respectively between 2001 and 2010.⁵ Melanoma also accounted for the fourth highest number of new cancer cases in two age groups: 15-29 years (8%) and 30-49 years (6%).⁵ As such, it is one of the fastest rising of all cancers in Canada, along with liver and thyroid cancers.^2,3,5 Luckily, melanoma is one of the most treatable of all cancers if diagnosed and treated early, with a survival rate of 89% within the first five years. This is the fourth highest survival rate among all cancers, after thyroid, testicular and prostate.⁵

In 2015, 1,150 deaths (750 males, 420 females) were attributed to melanoma,⁵ while between 2006 and 2010, deaths due to melanoma accounted for 4% of all deaths due to cancer in individuals 15-29 years of age.⁵ As of 2010, the lifetime percentage likelihood of dying from melanoma is only 0.4% in males and 0.2% in females^‡.⁵ Looking to the future, the number of new melanoma cases between 2003–2007 and 2028–2032 is expected to increase, on average, by 72% (males 75.4%; females 68.7%).⁵

Although melanoma has a high survival rate, it still presents a burden on the Canadian economy. Unfortunately, limited data are available on the current economic cost; however in 2004, the total burden was estimated at $532 million annually, with $444 million (83.4%) for melanoma and $88 million (16.6%) for non-melanoma.⁶ This total amount is expected to rise by 2031 to $922 million annually, with $696 million (75.5%) for melanoma and $226 million (24.5%) for non-melanoma.⁶ In addition, a 2009 study of cancer costs in Ontario showed that melanoma was the least costly cancer to treat ($9,757 for the first year of treatment), compared to colorectal ($37,014), lung ($31,550), female breast ($20,740), and prostate ($14,545) cancers.⁷

Cimate change will also add complexity to this issue as it is expected to have significant influence on human health, including skin cancers.⁸ The atmospheric ozone layer is responsible for absorbing UV rays from the sun, but ozone depletion, caused by greenhouse gas emissions, has led to increases in the duration (warmer weather leads to more outdoor activities) and intensity of UV radiation exposure.⁸ This, in turn, is causing the northern regions (especially the Arctic) to warm more quickly than the south,⁹ so that individuals living in Canada may experience an increasingly higher risk of melanoma.

Luckily, skin cancers are one of the most preventable cancers, with such simple prevention means as:²

1. Scheduling outdoor activities for before 11:00 am and after 4:00 pm, when the sun is not at its highest, OR when there is a UV index of 3 or less;
2. Wearing appropriate clothing – hats with a wide brim, sunglasses, UV protective clothing;
3. Applying sunscreen labelled “broad spectrum” and “water resistant” with a SPF of at least 30, on all areas of the body not covered by clothes;
4. Seeking shade where appropriate; and
5. Avoiding indoor tanning.²

Our colleagues in Australia (home of some of the highest rates of skin cancer) have it down to the five S’s: slip, slop, slap, seek and slide.¹⁰ A campaign video featuring Sid the Seagull reminds people of the five things they can do to prevent skin cancer. This campaign, combined with the SunSmart program, has been one of the most successful health campaigns in Australia and is credited with preventing more than 103,000 skin cancers in Victoria between 1988 and 2003.¹¹ It is also cost effective, with a net saving of $2.30 (AUD) for every dollar spent on the program.¹¹ Its success is attributed to the integration of research and evaluation into the program, and ensuring program consistency and continuity.¹²