Skin cancer

Skin cancers are the most common forms of cancer in the western world. The vast majority are due to sun damage and previous episodes of sun burn. Most are not life threatening. Everyone needs to self monitor their skin and see a Dermatologist if any new skin lesions develop or if existing skin lesions change.

Skin condition: Skin Cancer

Skin cancers are the most common forms of cancer in the western world. People with pale skin are far more affected than those with darker skin. One of the confusing aspects of a skin cancer diagnosis is trying to understand how serious it is. In the vast majority of cases, when detected early and removed, a skin cancer will not be life threatening. Unfortunately, in a small proportion of cases, skin cancers can spread beyond the skin becoming difficult to treat and in a small number of people they can be fatal. It is therefore important to understand which type of skin cancer you have got.

What is this skin condition?

Cancers occur when cells start to divide in an uncontrolled and excessive way. Most cells in the body regenerate to some extent. The growth of all cells in the body is determined by the genetic code contained in all cells and there are specific genes that control cell growth. There is usually very precise control over this growth. Under certain circumstances this control can be damaged, normally when mutations occur in cell growth control genes. Cells start to grow too much and in some cases grow beyond their normal location and spread around the body.  Gene mutations occur for a number of reasons

  1. Rarely, a tendency to gene mutations can be inherited
  2. The ageing process leads to an increase chance of gene mutations
  3. The most common reason for gene mutations is due to damage from external, environmental causes such as ultraviolet radiation in sunlight; UVB and UVA.

Cancers can occur from any cell type but are more common in cells that a continually growing and regenerating such as the skin. Within the skin there are many different cell types but cancers occur most commonly in 3 cell types

  1. Basal cell skin cancer
    1. Are derived from cells near hair follicles
    2. Occur most commonly on sun exposed areas
    3. In the vast majority of cases do not spread around the body
    4. If left for too long they can grow locally and invade into fat, muscles or nerves
    5. Come in various different types including superficical, nodular, morphoeic, pigmented, cystic
  2. Squamous cell skin cancer
    1. Develop in normal skin cells- the keratincoyes. These are the cells that make up most of our skin.
    2. Are more common with prolonged episodes of sun damage
    3. Will often arise from areas of sun damaged skin.
    4. Sun damaged skin lesions called actinic keratosis or Bowens disease occur due to keratinocyte damage and can progress to become squamous cell skin cancer
  3. Malignant melanoma
    1. Develop in the pigment cells
    2. Most types are due to sun damage but rare forms can occur on the sole of the foot which clearly has other cause
    3. Can arise in pre-existing moles or can appear in previously normal skin
    4. When pigment cells first start to grow abnormally they stay within the top layers of the skin and are called lentigo maligna. If removed at this stage they are cured.
    5. Once malignant melanomas have grown into the second layer of skin, the dermis, they develop the potential to spread further. The severity of a malignant melanoma is determined by how far they have grown into the dermis and this measurement is called the Breslow thickness. The thicker the Breslow the worse the prognosis. A patient with melanoma with a Breslow thickness of less than 0.76mm is very unlikely to die from their melanoma.

Other rare skin cancers include

  1. Merkel cell cancer
  2. Angiosarcoma
  3. Dermatofibromasarcoma protuberans
  4. Kaposi’s sarcoma
  5. Sebaceous gland carcinoma

There are many other types of cell overgrowth in the skin which will not be discussed in this article.

 

Why have I got it?

In the case of skin cancer, the most common cause of gene mutations is ultraviolet radiation in sunlight . Every time we get sunburnt our skin is being damaged and gene mutations are occurring. The body has many, clever ways of repairing gene mutations but these are not perfect. One mutation in a single gene is unlikely to directly lead to a cancer. However, with repeated episodes of UV damage, multiple genes become damaged and eventually some are not repaired. This sets the scene for the development of a skin cancer.

 


 

Comparing the treatment options

Self-treatment

There is no self-treatment option for skin cancer. You need help from a Doctor. You can of course reduce your risk of getting a skin cancer by not getting sun burnt. You can improve your chance of a complete cure by showing new skin lesions to your GP or Dermatologist as soon as possible.

Help from your GP

Skin cancers are usually treated by specialists. However, if your GP is experienced in Dermatology they may be happy to treat milder skin cancers such as non-facial basal cell skin cancer. There are a variety of creams that can work quite well (see below).

Help from a Dermatologist

1. Basal cell skin cancer

The choice of treatment for a basal cell skin cancer will depend on the type of BCC, the size and the location. Different treatments have different success rates with some treatments giving a higher risk of tumour recurrence. Follow this link to the British Association of Dermatologists information sheet.

If your BCC is small or a superficial type and is not on your face you may be offered treatment with either creams, liquid nitrogen or curettage. These treatments do have a slightly higher risk of recurrence than surgery but are quick, usually very effective and often produce less scarring.

Creams

There are a variety of creams that are used for superficial basal cell skin cancers. The most commonly used are efudix and imiquimod. Click her to see the British association of Dermatology information sheets; efudix, imiquimod. Both creams trigger quite a lot of inflammation in the skin but once this has settled the cosmetic results are normally very good.

Google images shows a wide selection of images of efudix treatment in progress. As you can see there is sometimes a lot of inflammation although this settles quickly once treatment stops.

Liquid nitrogen is used to destroy the abnormal skin cells. The liquid nitrogen is stored in a canister and an aerosol of liquid nitrogen is sprayed onto the skin. The water in the skin cells freezes and this damages the skin cells leading to cell death. Inflammation usually occurs for up to 5 days following treatment followed by healing.

Curettage and cautery. Curettage involves scrapping away the abnormal skin cells. This produces a graze that normally bleeds slightly. The cautery stops the bleeding. The process is normally repeated 3 times to make sure that all of the abnormal cells have been removed.

For larger BCCs the best option is usually surgery under local anaesthetic

Skin excision. Excision is the word used by Doctors to describe cutting out an abnormal area of tissue such as a skin cancer

MOHS micrographic surgery is a specialised technique used to remove some skin cancers. If the skin cancer is well defined it is not normally needed. However, if the edges of a skin cancer are hard to see or if the cancer is in a cosmetically sensitive site such as the mouth, eyelid or nose then it can be very useful. In MOHS surgery the skin cancer is removed and the edges of the sample are checked, while you wait, to make sure it has all been removed. This allows the MOHS surgeon to remove the minimum skin possible whilst being 100% certain that all of the cancer has been removed.

This sequence of images shows how the treatment of a BCC using MOHs surgery.

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LB 26.9.14 DSC_0128 E

 

 

2. Squamous cell skin cancer and Malignant melanoma

In the first instance surgery is really the only option for these cancers. In the event of the cancer spreading further there are often many options for treatment including further surgery, chemotherapy and radiotherapy. Discussion of these options is complex and if you need information about these issues please consult your Dermatologist, Plastic Surgeon or Oncologist.

Follow these links to the British Association of Dermatologists information sheets:

1. squamous cell skin cancer,

2. lentigo maligna

3. maliganant melanoma stage 1, stage 2, stage 3, stage 4


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