With summer just around the corner in Europe and America, it's time to think about the risk of too much sun exposure.  One greater hazard has less risk - melanoma - but though it is less common than some other types of skin cancer, it is more likely to grow and spread. 

In 2019, an estimated 96,000 new melanomas will be diagnosed and men are far greater impacted than women. About 7,000 people will die, nearly twice as many men as women. It is 20X more common in people of Caucasian descent than people of African descent. Though the average age of diagnosis is 63, it defies the cancer stereotype in young people, being one of the most common cancers in young adults.

1. Though sun exposure is an important factor in the development of melanoma, so it often appears on the face, neck, arms and torso, where sun exposure is common, it can also occur on areas with minimal sun exposure, such as palms and soles of the feet. UV exposure (sunlight) is a risk factor. Like many cancers, age is a big risk factor, but a weakened immune system if you are receiving some medical treatment is a factor. For example, people who get organ transplants are usually given medicines that weaken their immune system to help prevent them from rejecting the new organ. This increases their risk of melanoma.

2. A specific mitogen-activated pathway is linked to mutations causing melanoma and genomic sequencing is helping identify markers for diagnosis and treatment. In non-jargon, peple with fair skin, freckling, and light hair are at greater risk. Your risk is higher if one or more of your first-degree relatives (parents, brothers, sisters, or children) has had melanoma. Around 10% of all people with melanoma have a family history of the disease.

3. About 10% of melanomas are challenging to diagnose as they may be pink, red, clear or normal skin-colored. 

4. Patients with any suspicious skin lesions should be referred to dermatology. Colored lesions with any of the ABCDE criteria -- Asymmetric shape, irregular Border, Color variation, Diameter greater than 6 mm (about the size of a pencil eraser) and Evolution (change) -- should be considered suspicious.

Citation: Robert Micieli and Kucy Pon, 'Five things to know about …: Melanoma', CMAJ May 13, 2019 191 (19) E535; DOI:10.1503/cmaj.181500