Basal cell carcinoma is also known as BCC, rodent ulcer and basalioma. It is a form of keratinocytic or non-melanoma skin cancer. Basal cell carcinoma is the most common type of cancer in humans and is particularly prevalent in the Australia and New Zealand. BCC is very rarely a threat to life.
BCC typically affects adults of fair complexion who have had a lot of sun exposure, or repeated episodes of sunburn. Although more common in the elderly, sun-loving New Zealanders frequently develop them in their early 40s and sometimes younger.
The tendency to develop BCC may be inherited. BCC is a particular problem for families with basal cell naevus syndrome (Gorlin syndrome), Bazex-Dupré-Christol syndrome, Rombo syndrome, Oley syndrome and xeroderma pigmentosum. Recent research has detected genetic defects in common BCCs as well as in patients with these syndromes.
BCCs arise in otherwise normal appearing skin, unlike squamous cell carcinomas (SCCs), which often arise within pre-existing actinic keratoses. They usually grow slowly over months or years so they can vary in size from a few millimetres to several centimetres in diameter. There are several different clinical types.
The treatment for a BCC depends on its type, size and location, the number to be treated, and the preference or expertise of the doctor.
Biopsy may be recommended to confirm BCC and subtype of BCC prior to selection of the most suitable treatment for an individual lesion. Various treatments are available for BCC and are described below.
Superficial skin surgery
Shave, curettage, cautery (electrosurgery, shave biopsy and other types of minor surgery). Many small, well-defined nodular or superficial BCCs can be successfully removed by removing just the top layers of the skin. The wound usually heals within a few weeks without needing stitches.
Excision means the lesion is cut out and the skin stitched up. This is the most appropriate treatment for nodular, infiltrative and morphoeic BCCs. A margin of normal skin should be removed to ensure complete removal, with 3 to 4 mm recommended for facial lesions. Very large lesions may require a flap or skin graftto repair the defect after excision.
If the tumour is reported as being incompletely excised, there is a risk of later recurrence. In many cases, further surgery will be recommended to remove a wider area of skin, particularly if the deep margin is thought to have persistent tumour cells.
Mohs micrographically controlled excision
Mohs micrographically controlled excision is a technique used for BCCs growing in high-risk areas of the face around the eyes, lips and nose. Ill-defined BCCs (any subtype), morphoeic BCCs and recurrent BCCs are also best removed by a dermatologic surgeon by the Mohs technique. This involves examining the carefully marked excised tissue under the microscope while the patient is still in the operating suite, layer by layer. It may take several slices until the tumour has been completely removed. The defect is often much bigger than the BCC appeared to be before surgery because of hidden extensions of tumour cells under the skin.
Photodynamic therapy (PDT) refers to a technique in which the tumour is treated with a photosensitising chemical in a cream (e.g. Metvix) or lotion (ALA), and exposed to light several hours later. 70 to 80% of small superficial BCCs are cured by PDT, with excellent cosmetic results. It is less successful for other types of BCC and is best avoided if the tumour is in a high risk site.
Imiquimod is an immune response modifier. It is best used for small lesions (less than 10mm on the face). The cream is applied to superficial BCCs three to five times each week, for six to sixteen weeks. The imiquimod results in an inflammatory reaction, maximal at three weeks. 70 to 80% of small superficial BCCs are cured, with minimal scarring. Long term follow-up is recommended as lesions may recur.
5-Fluorouracil cream is sometimes used for very superficial small basal cell carcinomas and can be successful if treatment is continued for long enough (e.g., 12 weeks, twice daily). Cure rates are lower than with imiquimod cream.
Cryotherapy is the treatment of a superficial skin lesion by freezing it. Dermatologists sometimes treat small superficial BCCs with liquid nitrogen, using a special double freeze-thaw technique. A blister forms, crusts over and heals within several weeks. A permanent white mark usually results from this treatment, but it is inexpensive and may be very suitable for lesions in covered sites.
Radiotherapy refers to X-ray treatment, and is less commonly used to treat BCCs than in the past. It may be suitable for skin cancers on the face in the elderly. The best cosmetic results are achieved using multiple fractions, e.g. once-weekly treatments for several weeks.
Vismodegib is a new treatment for advanced or metastatic basal cell carcinoma, approved by the FDA in March 2012.
Whatever the chosen treatment, BCC can nearly always be cured.
Patients with BCC are at increased risk of developing further BCCs. They are also at increased risk of other skin cancers, especially melanoma. Arrange a complete skin examination from time to time. Ask your dermatologist or GP to check any persisting or growing lumps or sores or otherwise odd-looking skin lesions. Early detection means easier treatment, and less scarring.
People who avoid sunburn in childhood and early life are at lower risk of BCC. It is very important that fair skinned individuals and those with a family history of BCC practice sun protection lifelong.
Stay indoors or under the shade in the middle of the day. Wear covering clothing. Apply broad spectrum sunscreens to exposed skin if you are outdoors for prolonged periods, especially during the summer months.
The number and severity of BCCs can also be reduced by taking nicotinamide (vitamin B3) 500 mg twice daily.