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SKIN CANCER SERIES - PART 2: SQUAMOUS CELL CARCINOMA

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is a very common type of skin cancer. Luckily, it is not usually a threat to life, as secondary growths are uncommon.

SCCs typically affect people of fair complexion. They develop in areas which have been exposed to the sun over a long period. They vary in size from a few millimetres to several centimetres in diameter. Sometimes they grow to the size of a pea or larger in a few weeks, and are often tender, though more commonly they grow slowly over months or years.

Rarely SCCs develop in old burn scars, injuries and ulcers.

What does a SCC look like?

SCCs often develop from actinic keratoses. These are harmless "sun spots", small red scaly patches occurring in sun damaged skin, especially on face, ears and hands. If the keratosis has become thicker or larger, it may be an SCC. It is often crusting and may bleed easily.

Some SCCs appear as sores which fail to heal. A common site is the bottom lip – if a sore has not gone in 3 weeks, get it checked. A pre-cancerous lesion known as Bowen's disease can precede SCC. This is a flat red scaly patch up to several centimetres wide, often found in large numbers on the lower legs. The development of a lump or bleeding in Bowen's disease may indicate the beginning of invasive SCC.

An alarming type of SCC is known as keratoacanthoma. This can develop into a dome-shaped nodule 2 or 3 centimetres in diameter over a few weeks! Luckily these are rarely dangerous, but untreated they can leave ugly scars. Surgical removal is usually recommended.

What happens if the SCC is left untreated?

Most SCCs slowly enlarge, making eventual treatment more difficult. Although keratoacanthomas often go without treatment, they are difficult to tell from invasive SCCs, which don't.

SCC can spread to other sites of the body (metastases or secondary growths). These usually develop in the lymph glands, and are most likely if the SCC is on the lip or ear. Secondary growths are more difficult to treat than the original skin lesion, as surgery may not always remove them completely. About 200 New Zealanders die every year from SCC.

How are SCCs treated?

The treatment for a SCC depends on the type, its size and location, the number to be treated, and the preference or expertise of the doctor.

  • Excision – The lesion is cut out and the skin is stitched up
  • Freezing – Dermatologists sometimes use liquid nitrogen with a special technique.
  • Shave, curettage and cautery (and other similar techniques) – Many skin cancers can be successfully treated by removing just the top surface of the skin. The wound usually heals rapidly without needing stitches
  • Plastic surgery – Those with larger lesions or one in a difficult site may be referred to a plastic surgeon. He may create a flap or graft to repair the defect after excision.
  • Radiotherapy (X-ray treatment) – can be used for some skin cancers, usually on the face.
Whichever the chosen treatment, squamous cell carcinoma can nearly always be cured. Rarely, SCCs come back at the same site, but they can be treated again safely.

What should I do now?

If you have had a SCC treated, you have a high chance of developing another one. Early treatment means easier treatment, and less scarring.

  • Make sure you protect your skin from the sun at all times
  • Arrange for a complete skin examination from time to time
  • Ask your dermatologist or GP to check any persisting or growing lumps or sores.