Basal cell carcinoma

What is Basal cell carcinoma?

Basal cell carcinoma (basal cell cancer or rodent ulcer) is the commonest type of skin cancer.

How does it occur?

The name basal cell carcinoma (BCC) is used because the cancer arises in the basal or deepest cells of the skin. Slightly less common is squamous cell carcinoma which begins in the more superficial squamous layer. By contrast, malignant melanoma, which the average lay person is more likely to have heard of, is much rarer than either of these.

Why does it occur?

The main cause of Basal cell carcinoma is cumulative damage to the skin from sunlight, so it is much more common in those with a pale complexion who spend a lot of time in the sun. It very rarely arises in parts of the body that are kept covered.

BCC tends to affect people in their 60s and beyond, but is now increasing in the under-40s and may become even more common with climate changes such as thinning of the ozone layer.

Accumulation of the element arsenic in the body is also a potential cause of BCC. Although arsenic is no longer used as a common ingredient of "nerve tonics", it is still sometimes present in small quantities, along with other toxic metals, in certain "traditional" medicines, for instance Ayurvedic remedies.

Another cause of BCC is a rare genetic condition called naevoid basal cell carcinoma syndrome, which results in a wide range of abnormalities as well as a family tree marked by BCC and other cancers.

What are the symptoms?

Around 9 out of 10 BCCs are on the face, usually near the ear, nose or eye. A BCC usually appears as a painless nodule which develops into an equally painless ulcer. The ulcer tends to have heaped up edges with a glistening pearly appearance, and nearby there are often a prominent cluster of small blood vessels.

What are the complications?

Left untreated, a Basal cell carcinoma enlarges and can bleed. It spreads by eating slowly into the underlying skin and adjacent tissues, hence its alternative name of rodent ulcer. If neglected, the tumour can grow to a huge size and become disfiguring.

It is often thought that BCC never spreads to more distant parts of the body as some other cancers (eg malignant melanoma) do. In fact BCC can spread, but this is extremely rare. That is why once a basal cell tumour is treated, it is usually cured for good.

What tests are done?

Although one can strongly suspect the presence of BCC simply from its appearance, the diagnosis can only be made for certain by a biopsy. It is done by either taking a sample of part of the ulcer (an incision biopsy) or, if it is still fairly small, by removing the whole ulcer (an excision biopsy) to have the cells examined under the microscope.

What is the treatment?

Treatment can be by

  • Surgery
  • Cryotherapy
  • Radiotherapy
  • Chemotherapy

The choice in each case depends on the size and location of the tumour. Surgical removal is often the preferred treatment and is in effect the same as an excision biopsy. It can be done under local or general anaesthetic, and it may, depending on the area affected, need the skills of a plastic surgeon.

Laser treatment is another possibility. Cryotherapy involves freezing the tumour with liquid nitrogen and can be suitable for small ulcers.

Radiotherapy can be very effective in curing BCC and is excellent for areas which aren't suitable for surgery. Occasionally, advanced BCC responds very well to chemotherapy.

What happens after treatment?

Surgery or radiotherapy often leaves at least a small scar, and temporary blistering is usual after cryotherapy.

Treatment of Basal cell carcinoma is usually effective but follow-up is still needed afterwards. Those who have had a BCC may be at higher risk of developing either another BCC or a different tumour, so prolonged or lifelong yearly follow-up may be recommended.

Sun protection is helpful in preventing further skin damage both for the BCC patient and their family. The avoidance of tanning is probably as important as preventing sunburn.

Last updated 14 June 2011


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