Skin Cancer



Last Review Date: March 15, 2016


What is it?

Our skin is a protective cover for our body. Like all tissues of our body the skin is made up of cells. The types of skin cancer are named after the cell of the skin from which the cancer arises. Basal cells of the skin give rise to basal cell carcinoma. Squamous cell carcinomas arise from squamous cells and melanomas from the melanin pigment containing cells (melanocytes). The common types of skin cancers are squamous cell carcinoma, basal cell carcinoma and melanoma. Basal cell carcinoma and squamous cell carcinoma are referred to as non-melanoma skin cancers. There are other rare kinds of skin cancer derived from nerves, blood vessels, sweat and oil glands and other skin components but they will not be covered here.

  • Australia has one of the highest incidences of skin cancer in the world.
  • ​Two in three Australians will be diagnosed with skin cancer by the age of 70.

Basal cell carcinoma (BCC) is the most common and least dangerous type of skin cancer. It grows very slowly on areas of the body that are exposed to the sun. Face and scalp are two of the common sites. These cancers never spread to distant parts of the body. BCCs cause damage by growing and invading into surrounding tissue.

Squamous cell Carcinoma (SCC) occurs in people over 50 years of age on sun exposed areas of the body. If not detected and treated early it can spread to other parts of the body (metastasise) and can be very dangerous.

Melanoma was the commonly diagnosed cancer among Australian adolescents and young adults between 2003 and 2007. More than one-quarter of all cancers in this age group were melanoma. Melanoma is the third most common cancer for Victorian women (following breast and bowel) and fourth most common cancer in Victorian men (following prostate, bowel and lung).

Melanoma arises from the pigment containing cells of the skin known as melanocytes. It can spread to other parts of the body and can cause death. However, if caught early it can be cured completely. Melanomas are primarily treated by surgery.

Causes

Skin cancers develop when the skin is exposed to UV Radiation. Sun exposure, tanning and using solariums are risk factors.

Risk factors for melanoma include:
  • Light hair, fair skin and light coloured eyes
  • Caucasian ancestry
  • Childhood history of intense sun exposure
  • More than 100 moles on the body
  • Parents, siblings, and children (close family) with history of melanoma
  • Abnormal looking moles on the body
  • Previous history of melanoma or non-melanoma skin cancer
  • Weakened immune system especially after organ transplant, HIV infection and if taking chemotherapy (medicine against cancer).


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                                                            Quick Read patient information sheet

Symptoms

Basal Cell carcinoma

BCCs appear as a pearly lump or a dry scaly area on the skin. The lesion might ulcerate and never heals completely.

Squamous cell Carcinoma

SCCs appear as a thick, red scaly spot that bleeds easily. The surface may crust or ulcerate.

Melanoma

Melanoma usually appears as a freckle, new pigmented spot or mole that changes colour, shape or becomes thick within weeks or months. Moles or spots suggestive of melanoma show one or more of the following features on examination. (ABCDs): Asymmetry, Border irregularity, Colour changes, a Diameter more than the size of a pencil eraser. For a detailed account of melanoma visit this Fact File from the Royal College of Pathologists of Australasia.


Tests

Skin examination 

Self-examination or examination by a doctor is carried out to check skin for moles, freckles and pigmented areas that appear abnormal in colour, size, shape, texture, bleed and do not heal completely. Learn how to do this at the Sun Smart website

Skin biopsy

This is a surgical procedure in which a small sample of skin is removed and examined under the microscope. A pathologist examines the tissue and makes the diagnosis. If the tumour is small and has been completely removed by the first surgical procedure, no further treatment is undertaken. If the pathologist can see that the tumour extends right to teh edge of the tissue removed, this means that there is still tumour tissue in the patient and further treatment will be required.

Dermatoscopy (also known as epiluminescence microscopy)

In this technique, the suspicious spot is covered with oil and examined with a brightly lit magnifying instrument by a skin specialist.

BRAF V600 mutation test 

This is a genetic test done on tumour tissue from a patient with stage III or stage IV metastatic cutaneous melanoma that cannot be removed surgically because it is too extensive or in too many different places. If the patient’s tumour is shown to be positive for the BRAF V600 mutation they may be eligible to receive the drug dabrafenib under the Pharmaceutical Benefits Scheme (PBS). BRAF is a gene that codes for a protein called B-Raf. B-Raf is involved in regulating cell growth and some mutations in this gene lead to unregulated growth of cancers that have these mutations. Dabrafenib is a drug that acts as an inhibitor of the B-Raf protein.
 


Treatment

Skin cancers are always removed. Non melanoma skin tumours (basal cell carcinoma and squamous cell carcinoma) are treated similarly and are discussed together below:

Early non melanoma skin cancers can be treated by burning (cautery), scraping (curettage) or freezing with liquid nitrogen (cryotherapy), radiation, application of ointments or surgical removal under local anaesthesia. The main aim is to remove the cancer and leave only a small scar.

In Curettage and desiccation a scoop like instrument (curette) is used to scoop out the non-melanoma skin cancer. An electric current is applied to control bleeding and kill remaining cancer cells, this procedure is called desiccation. Small cancers are treated with this method.

Surgical excision involves application of local anaesthetic to numb the area and the entire cancer is removed. Stitches are applied to close the wound and aid healing.

Radiation therapy is used to treat skin cancer in areas difficult to reach for surgical intervention.

Cryosurgery involves application of liquid nitrogen to freeze and kill the cancer cells.

Mohs micrographic surgery, also known as "microscopically controlled excision" is a procedure in which small pieces of the tumour are removed and examined under the microscope during surgery. Sequential cutting and microscopic examination is repeated and the non-melanoma cancer is mapped and taken out without having to guess the width and depth of the lesion. This is a method of choice for large basal cell carcinomas, recurrent non-melanoma tumours and cancers on those parts of the body with high recurrences after treatment by other methods.

Creams and ointments can be used to treat small non melanoma skin cancers. Drugs, like 5-Fluorouracil (5-FU) are used to kill cancer cells. Other drugs that stimulate the immune system like imiquimod can also be used. This treatment can be performed at home.

Advanced squamous cell carcinomas are removed with the surrounding tissue and sometimes lymph nodes draining the cancer area to ensure that all the cancer is removed. The type, site, size, location of the tumour, the person’s age, general health, medical history, risk of scar formation and grade and stage of tumour are considered in planning the treatment.

There are various types of treatment available for melanomas. The treatment type depends upon the type of melanoma, thickness, location on the body, age of the person and stage of the tumour.

  • Surgery is the primary treatment of all stages of melanoma. Various types of surgery include one or more of:
    • Wide local excision: In this procedure the melanoma and some of the normal tissue around it (less than 1.5 cm) is removed. Some of the local lymph nodes may also be removed.
    • Lymphadenectomy: A surgical procedure in which the lymph nodes draining the area of the tumour are removed and samples of tissue are examined under a microscope to see if melanoma cells are present.
    • Sentinel lymph node biopsy: In this procedure a radioactive substance and/or a blue dye are injected close to the tumour. The radioactive substance or dye flows via the lymph vessels to the lymph nodes. The first lymph nodes to receive the substance and/or dye are removed (Sentinel node). A pathologist views the sentinel lymph nodes under a microscope to look for melanoma cells. If melanoma cells are found another operation to remove all lymph nodes in the area is performed.
    • Skin grafting involves removal of skin from another part of the body to replace the skin that is removed from the area of the tumour. This is usually performed if a large area of the skin is involved by the tumour.
  • Chemotherapy: Drugs are used to halt the growth of cancer cells. These drugs either kill the tumour cells or prevent them from dividing. Chemotherapy is given to kill the tumour cells that might remain in the body after the surgery and to prevent the cancer from coming back.
  • Radiation therapy: High energy X-rays or other types of radiation is used to impede cancer cell division and kill the cancer cells. The two types of radiation therapy are: External and internal radiotherapy. The type of therapy used depends on the stage and type of melanoma.
  • Immunotherapy therapy: Also known as biotherapy. This method involves the person’s immune system to combat the tumour. Interferon, interleukin-2 (IL-2) and tumour necrosis factor (TNF) are currently used against melanoma.
  • Targeted therapy: Involves drugs that specifically identify and kill tumour cells without doing any harm to the healthy cells. These treatments are still under development.

Prevention

All skin tumours can be prevented by:

  • Avoidance of sun exposure: Reducing sun exposure plays important role in preventing all types of skin cancer. This can be done by wearing hats, use of tightly woven clothing and application of waterproof sunscreens.
  • Early detection: Regular self-skin examinations and skin examination by your doctor. Public awareness of the symptoms of the common skin cancers can lead to early cancer detection with early treatment and prevention of spread of the cancer.
  • Screening of high-risk individuals: Anyone at high risk, such as a person with a close relative who has had melanoma or other skin cancer. Any individuals with previous history of any type of skin cancer should have regular check-ups for early detection and prevention of skin tumours.

Related Pages

On this  site
Anatomical pathology

Elsewhere on the web

Cancer Council Australia – Skin Cancer

Sun Smart

Melanoma Patients Australia

 

Sources

Staples M, Elwood M, Burton R, Williams J, Marks R, Giles G. Non-melanoma skin cancer in Australia: the 2002 national survey and trends since 1985. Medical Journal of Australia 2006; 184: 6–10.

Australian Institute of Health and Welfare (AIHW). Cancer in adolescents and young adults in Australia. Cancer series no 62. Cat no CAN 59. Canberra: AIHW, 2011. Available from http://www.aihw.gov.au/

Thursfield V, Farrugia H. Cancer in Victoria: Statistics and trends 2010. Cancer Council Victoria: Melbourne, Australia, December 2011.

National Cancer Institute - Melanoma Treatment  (USA)

American Joint Committee on Cancer - Melanoma of the Skin Staging (pdf)

Pathology and Genetics of Tumours of the Skin, World Health Organization Classification of Tumours. Edited by D. Weedon, P. LeBoit, G. Burg and A. Sarasin, 2005.