Skin Cancer – Overview
Skin cancer is very common. It is the second most common cancer in young people (age 15-34), but the risk of developing the disease still increases with age. It is believed that 70% of people who are over 55 will develop some form of skin cancer in their lifetime.
The cancer develops when abnormality occurs in a regular repair and life cycles of skin cells. The growth of particular cell group may become uncontrollable, and collection of abnormal cells develops forming a tumour. Skin tumour can be non-cancerous (benign) and cancerous (malignant), with a spectrum of abnormalities known also as pre-cancerous sun damage.
Skin cancer may first appears as a change in a pre-existing mole or a patch of normal skin. Skin cancer needs to be treated as it will not mend itself spontaneously.
Types of skin cancer
There are two main groups: non-melanoma and melanoma skin cancers.
Non-melanoma skin cancer
- Basal Cell Carcinoma (BCC) is far the commonest type and represents approximately 80% of all skin cancers. It grows slowly and causes local problems only. Most people simply become aware of a discrete change which “never disappears properly and for good”. It is very unlikely for these type of cancers to spread (metastasize) to other parts of the body (please see BCC leaflet), but this has been described and is seen clinically very rarely
- Squamous Cell Carcinoma (SCC) is the second most common type. Appearances vary, but in many cases surface of the lesion is crusty. They also grow slowly, like BCC, but can metastasise and should, therefore be recognised early and treated radically (please see SCC leaflet)
- There are other 22 types of non-melanoma skin cancers, but they are very rare and each one is treated on its own merits pending exact clinical picture
Melanoma is much more serious, but thankfully less common then BCCs or SCCs. It arises from melanocytes (pigment producing cells) in the skin, hence the name and often darker discoloration of these lesions (dark brown/black). Rarely (5%), melanoma can be without the pigment (so called amelanotic melanoma) and appear as a lighter (pink or red) lesion. Melanoma arises from the pre-existing moles in 30% of cases. Majority, however develop as a completely new lesion. Repeated bleeding from the lesion present for over 4-6 weeks is a particularly alarming sign and such lesions must be checked by an expert at the earliest convenience.
Causes and Risk Factors
- ultra-violet radiation (UVR) from the sun or sunbeds (outdoor work, sports and hobbies) – UVR damages the genetic material (DNA) in skin cells and interferes with normal cell cycle
- prolonged exposure to some chemicals and irritants
- long standing ulcers, burns and unstable scar tissue
- previous radiotherapy
- genetic predisposition – people with fair skin, lots of moles or freckles, or with family history of skin cancer
- immunosuppresion – people with transplanted tissues
Signs of skin cancer
You may have some moles or dark patches on your skin that are flat or slightly raised. Usually these will remain harmless all your life. Those that change in size, shape or colour over weeks or months are likely to be of clinical relevance. Especially lesions which never disappear, but enlarge slowly.
Check your skin regularly for changes; this is especially important if you are fair skinned with lots of moles or freckles. The ABCD rule can help you remember what to look out for. If you notice any of the following signs, see your doctor without delay:
The ABCDE rule
Asymmetry – the two halves of a lesion may not look the same
Border – Edges of a lesion may be irregular, blurred or jagged
Colour – The colour of a lesion may be uneven, with more than one shade
Diameter – many melanomas are at least 6mm in diameter
Evolving – lesion changes over time
Other signs of Skin Cancer
- A new growth or sore that will not heal
- A spot, mole or sore that itches or hurts
- A mole or growth that bleeds, crusts or scabs
Any change in a mole, freckle or normal patch of skin that occurs quickly, over weeks or months, is worth getting checked out.
Please note that this leaflet provides only basic and generic information, but full details and explanations are provided at the consultation.