Basal Cell Carcinoma.

BCC is the most common type of skin cancer.

What is a BCC?

A BCC (Basal Cell Carcinoma) is the most common type of skin cancer. BCC is a very common finding at a skin cancer examination. The cancerous cells originate from the most bottom layer of the epidermis.

BCC has a reputation as being a nuisance rather than being serious. Certainly, BCC is slow growing and only rarely spreads to other parts of the body. However, early diagnosis of BCC is advantageous for these reasons.

  • ‘Superficial BCC’, if caught early, can be treated with a cream rather than surgery.
  • Nodular BCC, in contrast, requires surgery. However, the extent of surgery that is required will reflect the size of the BCC. Nodular BCC is removed with clear margins. Let’s illustrate the scar size with numbers. Take a small BCC that is just 4mm in diameter. The BCC is cut out with 3mm margins, resulting in a scar that is 24mm long. Now take a 6mm BCC. The scar is now 30mm long. In fact, for every extra 1 mm in diameter, the scar will be 3-4mm longer. This is clearly an issue on the face or scalp where a skin graft or flap may be required. Bear in mind that these figures are conservative, and some types of BCC will need a wider excision.
  • BCC can still, albeit it very rarely, spread (metastasize) to other areas of the body.

BCC may need to be cut out with much wider margins that you think.

Who is at risk of BCC?

BCC is very common in Australia. UV light is of course the major risk factor for BCC (primarily UVB). Intermittent intense exposure to sunlight is important, as well as long term cumulative sun exposure. Use of tanning machines increases risk around 1.5 fold.

Genes are an all-important risk factor for the development of BCC.

Interestingly, emerging evidence suggests that BCC is more common with lower Body Mass Index. Estrogen increases with higher body weight, and estrogen is thought to protect against BCC.

Immunosuppression is a strong risk factor for BCC, with a tenfold increase on the trunk and arms after a solid organ transplant.

Other common risk factors are prior radiotherapy and immunosuppression (though less important than with SCC). Rare risk factors are arsenic exposure and some hereditary conditions such as nevoid basal cell carcinoma syndrome.

The clinical types of BCC

There are different types of BCC requiring different treatments. The broad category of BCC may be established clinically prior to excision. However, the pathology report is required to identify any concerning features and to confirm the BCC subtype.

Let’s describe the two main types of BCC:

  • Nodular BCC is raised, shiny, may be pigmented & usually occurs on the face. Nodular BCC needs to be surgically removed.
  • Superficial BCC is flat, pink, & is most commonly found on the trunk or limbs. Superficial BCC may be treated with skin cancer cream.

Now let’s look at all the main types of BCC in more detail.

Superficial BCC accounts for around 30% of Basal Cell Carcinoma. The condition tends to occur in a younger age group than those affected by other BCC types. Genes play an important role in the development of superficial BCC.

Superficial BCC appears as a pink or red flat lesion with well defined borders. Look for a subtly elevated and/or pearly edge that is best seen on stretching the skin. The lesion may be slightly shiny and/or  scaly. Superficial BCC may look similar to an IEC (Bowens disease). A dermatoscope will certainly help distinguish the two with at least 90% accuracy.

Superficial BCC may be treated non-surgically. The most common non-surgical treatment is with Imiquimod (®Aldara) cream.

superficial BCC 2

superficial BCC – note how spreading the skin is the best way to see the colours and texture. (Image reproduced with permission from PCDS.org.uk)

superficial BCC - typical

This superficial BCC is really typical – the red colour has a bluish tinge to it and there are some small erosions within the lesion.