Melanoma: how to spot the spots

Sarah Ferguson, the Duchess of York, has revealed that she has been diagnosed with malignant melanoma. The 64-year-old author - and former high-profile member of the Royal family - said she was "grateful” for the “love and support" she had received, and urged people to look out for signs of potentially cancerous moles.

Rhys - Malignant melanoma affects more than 300,000 people around the world each year, and its ability to metastasise - or spread - to other parts of the body can make it particularly pernicious. The disease accounts for only 4% of all skin cancers, but is responsible for 75% of deaths caused by these malignancies.

Melanoma UK says your chance of surviving it largely depend on how early it's caught. If it doesn’t spread to your lymph nodes - or another part of your body - then it is highly likely that simply removing it will cure you.

So, what should we know about how it develops in the first place?

Melanoma is caused by ultraviolet light - and in particular UV-B rays - from the sun and also sun tanning beds. The light damages the DNA in melanin-producing cells in the deepest layers of our skin. This stops the cells repairing their DNA from further damage, and locks them into an uncontrolled growth cycle.

Although melanoma cases have roughly doubled since the 1990s, some of us are at greater risk than others. People with fair skin, fair hair and freckles are particularly susceptible, as are those with a history of the disease in their immediate family. Intense and intermittent sun exposure - including frequent sunburn - is associated with the greatest risk. The average age for diagnosis is 66 - but it is not uncommon for people in their 30s to develop it.

Thankfully, greater awareness has led to a reduction in the number of children dying from melanoma in recent years. This has been in no small part due to successful health campaigns run around the world, including in Australia and New Zealand, which have the highest global rates of melanoma. The famous “Slip! Slop! Slap!” campaign in the 1980s - which featured Sid the seagull encouraging people to slip on a shirt, slop on the sunscreen and slap on a hat - remains great advice to reduce and avoid sun exposure.

So, what should we be looking out for if we think something isn’t quite right?

Sarah Ferguson said her melanoma was discovered following the removal of what turned out to be a cancerous mole during treatment for breast cancer. The NHS advice here in the UK says that, in order to catch the disease as early as possible, we should all be looking out for “new” moles, a change in an existing mole, large moles, and even moles that are either an uneven shape or a mixture of colours, and especially those that are particularly dark, itchy or tend to bleed.

If melanoma is caught early, it’s likely that it will not cause further problems. The first step in treatment is usually surgery to remove the affected area and check that it's been completely excised. This is curative in the majority of cases. But some people will present with disease that has already spread from the primary site, or return with a relapse later, in which case patients are treated with chemo- or immunotherapy.

Professor Sarah Allinson has written a great piece in The Conversation about the huge improvements in treatment over the past decade, including the development of drugs, such as dabrafenib and trametinib. These new agents prevent cancerous cells from growing and also allow the immune system to recognise them as hostile and destroy them. Some patients have now been "cured" with these therapies, despite presenting with extensive disease, proving that they can work in some cases. Now the race is on to work out how to make the process as effective for everyone.

Nevertheless, when it comes to cancer, prevention is, of course, always better than cure. So, be sure to remember the advice of Sid the seagull and slip on a shirt, slop on the sunscreen and slap on a hat. And if you notice that you have new moles, a change in an existing mole, or large moles then speak to your doctor and get yourself checked out as soon as possible.