Skin cancer

Published by Bupa's Health Information Team, September 2010.

This factsheet is for people who have skin cancer, or who would like information about it.

Skin cancer is an abnormal and uncontrolled growth of cells in the skin, causing a tumour.

Animation - How cancer develops

A Flash plug-in is required to view this animation.

About skin cancer

The skin

Your skin is made up of three layers:

• the epidermis
• the dermis
• the supporting subcutaneous layer of loose tissue and fat

Cancer can start from cells in any of these layers.

Types of skin cancer

There are two main types of skin cancer: non-melanoma skin cancer (NMSC) and melanoma.

Non-melanoma skin cancer (NMSC)
An estimated 100,000 people are diagnosed with NMSC in the UK each year.

NMSC mostly occurs in areas of your body that are exposed to the sun, such as your head or neck. There are different types of NMSC, which are named after the cells they form from. The most common types are found in the top layer of your skin (the epidermis).

• Basal cell carcinoma (BCC). Three out of four people diagnosed with NMSC have BCC. It usually grows slowly and doesn't normally spread to other tissues. If left untreated, a BCC will turn into an ulcer, growing deeper into your skin and can damage other areas such as your bone.
• Squamous cell carcinoma (SCC). Around one in five people with NMSC have SCC. An SCC can spread into your surrounding skin. It can also spread to other areas of your body, but this is rare.

Melanoma
Melanoma is an overgrowth of the cells known as melanocytes. These are cells that make a pigment called melanin when your skin is exposed to the sun. Melanoma is the most serious form of skin cancer but it's curable if found early.

Melanoma can spread to other parts of your body (through your blood or lymph system) where it may grow and form secondary tumours. This spreading is called metastasis.

Around 10,300 people are diagnosed with melanoma each year in the UK. It affects slightly more women than men.The most common place for women to develop melanoma is on their legs; for men, it's on their chest or back.

Symptoms of skin cancer

Skin cancer is often painless and each type can look different.

• BCC often appears as a small red or pink, waxy or shiny lump.
• SCC often appears as a small pink lump with a hard or scaly or crusty skin.
• Melanoma usually starts as a dark spot or mole. If a melanoma spreads to other parts of your body, you can develop other symptoms such as swollen lymph nodes (glands throughout your body that are part of your immune system).

Symptoms that may indicate skin cancer include any mole, spot, lump or patch that:

• doesn't heal after four weeks
• gets bigger - especially over 7mm (a quarter of an inch) in diameter
• changes shape - look for an irregular edge
• changes colour - darkens, becomes patchy or multi-shaded
• becomes inflamed
• is itchy or painful
• bleeds or is crusty

These symptoms aren't always caused by skin cancer but if you have them, see your GP.

Causes of skin cancer

The causes of skin cancer aren't fully understood at present. But there are certain factors that make skin cancer more likely. The main risk factor for any type of skin cancer is over-exposure to sunlight.

You may also be more likely to get skin cancer if you:

• have fair skin that burns easily
• have a lot of moles (more than 100)
• have red or fair hair and blue or green eyes
• have lots of freckles
• have certain skin conditions - for example scarring from burns or skin ulcers
• have had repeated sunburn, especially during childhood
• have close relatives who have had skin cancer
• use a sunbed
• work outdoors
• smoke
• have a weakened immune system - for example, if you have HIV/AIDS, or are taking medicines that suppress your immune system
• rarely, have been exposed to certain chemicals

Age is also a factor - NMSCs are more common in people over 60 and are rare in children under 14.

Diagnosis of skin cancer

Your GP will ask about your symptoms and examine you. He or she may also ask about your medical history. Your GP may refer you to a dermatologist (a doctor who specialises in skin conditions) to have further tests including those listed below.

• A biopsy - a sample of your skin is taken and sent to a laboratory for testing.
  
• Scans - these may include X-rays, CT scans, MRI scans or ultrasound scans.
  
• A sentinel lymph node biopsy - an investigation which can help your doctor to find out if the cancer has spread to your lymph nodes.

Treatment of skin cancer

Your treatment will depend on your age, the type of skin cancer you have, where it is and whether it has spread.

There are a number of treatments for skin cancer, which are described below. Your doctor will advise you on which is best for you.

Surgery

There are different methods of surgically removing skin cancer depending on the type of skin cancer you have.

Your surgeon will aim to remove the cancer and some of the healthy skin surrounding it. The amount of healthy skin that is removed will vary depending on the type of cancer and how deep it is in your skin. For NMSC, the amount of healthy skin removed varies between 4 and 6mm. Melanoma is removed with a small margin of healthy skin. This skin is analysed in a laboratory and if it's found that not all of the cancer was removed, a further margin of healthy skin is removed around the scar.

Your surgeon may also remove some of your lymph nodes if they are found to be cancerous or if he or she wants to check that they are healthy.

Non-surgical treatments

There are several different types of non-surgical treatment for skin cancer, including the following.

• Photodynamic therapy - this is a fairly new treatment for BCCs. It uses a cream that makes your skin sensitive to light. Your skin is then exposed to a laser, which kills the cancer cells.
  
• Freezing and destroying BCCs with liquid nitrogen.
  
• A prescribed cream called imiquimod, which uses your immune system to attack BCCs.
  
• Retinoid treatment, given as tablets.
  
• Biological therapies - manufactured antibodies such as interferon help your immune system to fight the cancer. A more recent advance in this area is the development of melanoma vaccines. However, they are only being used in research trials at present.
  
• Radiotherapy - X-rays are used to kill cancer cells. You may have radiotherapy if the cancer covers a wide area or after surgery to stop the cancer coming back.
  
• Chemotherapy - medicines are used to destroy cancer cells. These are usually given as injections or tablets.

Prevention of skin cancer

To reduce your risk of skin cancer, always take care in the sun and don't let your skin burn. If you're spending longer than a few minutes out in the sun in the middle of the day (between 11am and 3pm):

• use a sunscreen with an SPF (sun protection factor) of at least 15 and that protects you against both UVA and UVB radiation
• stay in the shade as much as possible
• cover up with suitable clothing and a wide-brimmed hat

You also shouldn't use sunbeds if you want to reduce your risk of skin cancer. If you notice any changes in your skin, visit your GP as soon as possible.

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.