Family history of melanoma: understanding your skin cancer risk

Melanoma is a type of skin cancer. The NHS says that a new mole or a change in an existing mole may be a sign, and that melanomas can appear anywhere on the body, though they are more common in areas often exposed to the sun. Some rarer types can affect the eyes, soles of the feet, palms of the hands or genitals.

The NHS says finding a melanoma as early as possible can mean it is easier to treat, which is why checking your skin matters particularly if you have a family history.

Cancer Research UK says your risk of melanoma is higher if you have a close relative who has also had melanoma. It says this is probably partly because we tend to share the same colouring and skin type as our close relatives. A close relative is defined by the charity as a parent, brother, sister, child, aunt, uncle or grandparent.

The risk is highest if the relative had melanoma when they were younger than 30, or more than one first degree relative has had melanoma. The NHS also lists a history of skin cancer in your family, or having had skin cancer before, among the things that make melanoma more likely, and tells you to mention it to the GP if you or a family member has had skin cancer.

Cancer Research UK says some families tend to have large numbers of moles, or moles that are unusual (atypical moles), which tend to be an irregular shape or colour and may be larger than usual. People who have lots of unusually shaped or large moles (atypical mole syndrome) have a higher risk of melanoma than the general population.

It says around 10 out of 100 cases of melanoma might be linked to an inherited gene change, and that a number of genes can be associated with an increased risk, including one called CDKN2A. This is known to cause an inherited condition called familial atypical multiple mole melanoma syndrome. People with that syndrome have more than 50 moles, some atypical, and at least one close relative who has had melanoma.

For the small number of families who carry these genes, the charity says sun protection is even more important.

UV light is the main driver. Cancer Research UK says that in the UK around 85 out of 100 melanomas are caused by too much UV light from the sun or sunbeds, and that the risk increases with age. The NHS lists the following as raising the chance of melanoma:

• Pale skin that burns easily in the sun.

• Red or blonde hair, and blue or green eyes.

• A large number of freckles or moles.

• A lot of sun exposure and sunburn in the past.

• Frequent sunbed use. Cancer Research UK says sunbed use increases melanoma risk, particularly before the age of 35.

The NHS suggests checking your skin for unusual changes, using a mirror or asking a partner or friend to check areas you cannot see. Normal moles are usually round with smooth edges, one colour and small. Melanomas are often an uneven shape, a mix of 2 or more colours, and tend to be bigger, often more than 6mm wide, and may change over time.

See a GP if you have a mole that has changed size, shape or colour, is painful or itchy, is inflamed, bleeding or crusty, if you have a new or unusual mark that has not gone away after a few weeks, including on the palms or soles, or if you have a dark area under a nail that has not been caused by an injury. The GP may take a photograph to send to a dermatologist, which is called teledermatology.

The NHS says staying safe in the sun is the best way to lower your chance of skin cancer. This means staying out of the sun during the hottest part of the day, 11am to 3pm in the UK, keeping arms and legs covered, wearing a wide-brimmed hat and sunglasses with UV protection, and using sunscreen with an SPF of at least 30 and at least 4-star UVA protection, reapplied regularly. Babies and children need particular protection because their skin is more sensitive.

If you have darker skin, the NHS says you have a lower chance of melanoma but can still get it, most often on the soles of the feet, palms of the hands or under a nail.