Different pathways for developing melanoma by body site

Linked Article:   Laskar et al. Br J Dermatol 2021; 184 :1085–1093. Melanoma is a form of cancer that can develop anywhere on the skin. It is the third most common invasive cancer in Australia and the fifth most common in the UK. Risk factors include sun exposure, skin type, hair colour, moles and genetic factors. However, there may be different pathways for how melanoma develops in a person depending on where the melanoma occurs. This means that the degree to which these risk factors cause melanoma may vary across different sites on the body. We investigated this idea in a study conducted in the UK and Australia, with 2617 people with melanoma and 975 people without melanoma. We examined whether the risk for melanoma was different across body sites for a range of risk factors including moles, hair, eye and skin colour, freckles, sunburn tendency, sun or tanning‐bed exposure and genetics. We found that people with lots of moles have a strongly increased risk for melanoma on the trunk, arms and hands, with a smaller increase in risk for melanoma on the head or neck. People with very fair skin colour had a greater increased risk for melanoma on their legs, feet, head and neck than on their trunk. By contrast, other risk factors increased risk for melanoma by similar amounts at different body sites, including genetic risk factors. Our results support the idea that there are different pathways for developing melanoma.