A squamous cell carcinoma is a type of skin cancer.

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

Squamous cell carcinoma (SCC) is a non-melanoma skin cancer (NMSC), and the second most common type of skin cancer in the UK.

NMSC accounts for 20% of all cancers and 90% of all skin cancers. SCC accounts for 23% of all NMSC.

What causes a squamous cell carcinoma?

The most important cause is too much exposure to ultraviolet light from the sun or other sources. This can cause the DNA of skin cells (keratinocytes) in the outer layer of the skin (the epidermis) to change. Sometimes this alteration in DNA allows the skin cells to grow out of control and develop into an SCC. Ultraviolet light damage can cause SCC directly, or sometimes it can induce a scaly area called an actinic keratosis or Bowen’s disease. These can change into SCC if they are not treated.

Squamous cell carcinomas can also develop in skin damaged by other forms of radiation, in burns and persistent chronic ulcers and wounds and in old scars. Certain human viral wart viruses can also be a factor. However, SCC itself is not contagious.

Who is most likely to have a squamous cell carcinoma?

The following groups of people are at greater risk of developing SCC:

  • Immunosuppressed individuals (people with reduced immune systems) either due to medical treatment, such as methotrexate, ciclosporin and azathioprine, or due to diseases which affect immune function, including inherited diseases of the immune system or acquired conditions such as leukaemia or HIV;
  • Patients who have had an organ transplant because of the treatment required to suppress their immune systems to prevent organ rejection
  • People who are more susceptible to sunburn;
  • People who have had significant cumulative ultraviolet light exposure, for example:
    • people who have lived in countries near to the equator, or who have been posted to work in these countries, e.g. military personnel, construction workers;
    • outdoor workers, such as builders, farmers;
    • people of advanced years, who have had a lifetime of frequent sun exposure;
  • People with skin conditions such as albinism and xeroderma pigmentosum that make them more susceptible to SCC.

Are squamous cell carcinomas hereditary?

 No, they are not, but some of the risk factors, such as a tendency to burn in the sun, are inherited.

What does a squamous cell carcinoma look like?

SCC can vary in their appearance, but most usually appear as a scaly or crusty raised area of skin with a red, inflamed base. SCCs can be sore or tender and they can bleed but this is not always the case. They can appear as an ulcer.

SCC can occur on any part of the body, but they are more common on sun exposed sites such as the head, ears, neck and back of the hands.

How will my squamous cell carcinoma be diagnosed?

 If your doctor thinks that the lesion on your skin needs further investigation, you will be referred to a Dermatologist. To confirm the diagnosis, a small piece of the abnormal skin (a biopsy), or the whole area (an excision biopsy), will be removed using a local anaesthetic and sent to a pathologist to be examined under the microscope. The results will usually be available within a week to ten days.

Can a squamous cell carcinoma be cured?

 The vast majority of SCCs are low risk skin cancers and can be cured. A small number can recur locally and/or spread (metastasise) to the lymph nodes or to other parts of the body.

How can a squamous cell carcinoma be treated?

Surgery is usually the recommended treatment. This involves removing the SCC with a margin of normal skin around it, using a local anaesthetic. The skin is then closed with stitches or sometimes a skin graft is needed. Sometimes other surgical methods are used such as curettage and cautery. This involves scraping the SCC away using local anaesthetic.

Radiotherapy can also be used to treat SCC. This involves shining a beam of X-rays onto the skin. Usually several sessions are required.

For advanced SCC, a combination of treatments may be used. For SCC that has spread to other parts of the body a combination of surgery, radiotherapy and/or chemotherapy may be used.