New Zealand has the unenviable title of Melanoma Capital of the World, just edging out Australia, according to figures released by Medical Epidemiologist Professor David Whiteman in 2016*. New Zealand has approximately 50 cases of melanoma per 100,000 compared with Australia's 48 per 100,000. Melanoma risk increases with an individuals exposure to ultraviolet radiation, particularly UVA radiation, along with genetic factors such as light skin colour, excess sun exposure (especially sunburns in childhood) and a large number of moles. New Zealand and Australia have high levels of ultraviolet radiation (UV) which is around 40% higher than the UV radiation experienced at similar northern latitudes. Both countries also have high proportions of individuals of European heritage making up their populations which have lighter skin types more susceptible to sunburn. New Zealand is located under more of the ozone hole than Australia and is also less polluted, allowing more UV through the atmosphere.
Over the years Australians have become more aware of the dangers of melanoma and have adopted a 'SunSmart' approach due to on-going skin cancer prevention campaigns. Workplaces and schools have adopted sun protection measures to decrease exposure to harmful UV radiation. The same 'SunSmart' approach is in place in New Zealand but there has been a lag in uptake compared with Australia. Rates of melanoma in New Zealand are still increasing in people over the age of 50, likely due to individuals sustaining extensive melanoma-causing sun damage prior to prevention campaigns and those melanomas are only appearing now. Australian melanoma rates are actually in decline so it is anticipated that with on-going public prevention campaigns, increased health funding and sustained effort from Skin Cancer Doctors and other relevant health professionals in treating this disease, New Zealand rates will start to reduce in the very near future also.
*Whiteman DC, Green AC, Olsen CM. The Growing Burden of Invasive Melanoma: Projections of Incidence Rates and Numbers of New Cases in Six Susceptible Populations Through 2031. Journal of Investigative Dermatology 2016; 136: 1161-71.
Choosing the best sunscreen can be tricky as there are many products on the market to chose from. Many people also wonder what different SPF values translate to in terms of sun protection, whether adding zinc is a good idea and what broad spectrum actually means.
To help answer these questions it is best to go back to the basics with sun protection. Most people are aware it is the ultraviolet radiation (UV) from the sun that causes skin damage. UVA rays deeply penetrate the skin and are responsible for photo-ageing in the form of skin wrinkling and solar lentigo (age spot) formation. UVB rays cause the skin to become red from sunburn.
A sunscreen's sun protection factor or SPF measures its effectiveness against UVB radiation. Broad-spectrum protection refers to the sunscreen's ability to protect against UVA + UVB radiation. The Australian and New Zealand standard for sunscreens (AU/NZ 2604:2012) is compulsory in Australia but voluntary in New Zealand. This means sunscreens that don't meet any international standard are still allowed to be sold in New Zealand, which is quite concerning!
A recent Consumer New Zealand independent test of 20 common sunscreens sold in New Zealand found several had SPF values of 5 or less but were marketed as having SPF values of 15 or more. This is a case of buyer beware and adds weight to the argument that the standard for sunscreens be mandatory in New Zealand instead of just voluntary. Access the Consumer New Zealand article here.
Sunscreens can be divided into two main groups: physical blockers + chemical absorbers. Physical blockers include zinc oxide and titanium dioxide which work by reflecting both UVA + UVB radiation. They are very minimally absorbed so potentially better for sensitive skin. One drawback with physical blockers is that higher concentrations don't rub into skin well and can leave white marks. Chemical absorbers include octocrylene + oxybenzone and work by absorbing UVA + UVB radiation.
The best place to start when choosing a sunscreen is to consider what skin type you have. If it is very light and mainly burns without sunscreen then a high value SPF such as 50+ with broad spectrum cover is recommended. If you have skin that only tans or is quite dark then a sunscreen with SPF 15+ may be quite satisfactory. If you have sensitive skin avoid sunscreen with a preservative called metholisothiazolinone (MIT) which can be responsible for skin irritation and allergic reactions. Adding in a physical blocker like zinc oxide in a low percentage eg. 10% to a chemical absorber sunscreen is likely to give you the best of both worlds but not make your skin look too white.
Also consider what you need the sunscreen for. Are you heading for a day on the beach where you'll be in the water, a round of golf where you be sweating a bit or are you stuck in the office and only going to see the sun on your lunch-break? If you are predominantly outside and active with potential for sweating or in the water then consider a sunscreen with water resistance also. It is recommended that sunscreen be reapplied every two hours and because sunscreen is often not applied in all areas exposed to the sun or applied thickly enough by some people it is important to remember other methods of sun protection also such as wearing a hat and long-sleeved shirt as well as sunglasses.
See Dermnet for another great resource on how to choose a sunscreen and further information about getting enough vitamin D.
Why is it a good idea to improve your skills in dermoscopy? Well while the basic principles of dermoscopy are simple, becoming an expert with dermoscopy is difficult and requires a lot of practice!
Dermoscopy is essentially skin surface microscopy that is used as a tool to help diagnose pigmented lesions and non-pigmented skin lesions and increasingly helpful at identifying inflammatory dermatoses.
In expert hands, dermoscopy can help improve diagnostic accuracy (some studies estimate this to be ~35%) particularly with identifying early melanoma. It can also reduce the excision rate of benign lesions such as seborrhoeic keratoses and benign melanocytic naevi.
Dermoscopy involves a lot of pattern recognition and at first can be quite overwhelming to a beginner who may become overcautious and paradoxically excise more lesions than are necessary. So seeing lots of patients and practising dermoscopy at every opportunity is important. It's not just about volumes, however, knowing what to look for is also key with dermoscopy. This is where Dermnet can be very helpful with their offering of free short dermoscopy CME modules where there are many dermoscopy stock photos as examples of various benign and malignant lesions. Dermnet also has quick modules on how to learn dermoscopy using the three-point checklist, pattern analysis and other algorithms for melanocytic lesions.
Have a look at Dermnet's dermoscopy modules here and pick one or two to do every month to upskill or refresh your dermoscopy knowledge.