Family doctor

Because the spotlight of attention for skin cancer is on melanoma, it is easy to forget other forms of skin cancer that are in fact more common. Although not as dangerous as melanoma, these cancers can become large necessitating large surgical procedures that could have been avoided with earlier detection. This article focuses on Basal Cell Carcinoma (BCC) Squamous Cell Carcinoma (SCC) and Actinic Keratoses that are a premalignant type of sun damage.

This is a cancer arising from the basal cells of the epidermis (top layer) of the skin. It is the commonest form of skin cancer. As with melanoma, sun exposure will predispose to BCC's. BCCs grow slowly over months to years, gradually expanding in size and becoming deeper. It is most unusual for them to metastasise (spread into lymph nodes or bloodstream), but they can invade into vital structures such as eyelids or nerves and be hard to completely remove. They can look remarkably innocuous. As they grow so slowly and often produce no symptoms, diagnosis can be missed or delayed. There are several different types of BCC:

Nodular BCCs appear as a pearly translucent bump in the skin. They may occasionally crust or bleed. They can appear in less sun exposed areas such as behind the ear or around the eyelids. They can invade deeply and need to be surgically removed.

Superficial BCCs appear as a red sometimes scaly patch of skin. The can resemble an area of dermatitis. They do not respond to eczema creams and persist, gradually increasing in size. They may bleed on being rubbed with a towel. They do not penetrate deeply into the skin initially and may be treated with liquid nitrogen or curettage (scraping off the skin). If neglected however they often become large and deeper, eventually requiring surgical removal which may become a large procedure.

Infiltrating BCCs are the worst sort of BCC and unfortunately often the hardest type to recognise. They appear as a scarred thickened slightly lumpy area of skin and may be very subtle. They can penetrate quite deeply and necessitate extensive surgery to remove, particularly if diagnosis is delayed.

This is the next most common form of skin cancer. It arises from the squamous cells of the epidermis (top layer of the skin). It is even more strongly linked to amount of sun exposure than melanoma or BCCs. They mainly occur from middle age onwards but I not infrequently see them in people in their 30s and occasionally 20s which reflects how damaging the New Zealand sun is. They can occasionally spread into lymph nodes or bloodstream although this is much less common than with melanoma.

SCCs typically appear as a lump in the skin with a hard scaly or crusted top. They are typically found in more sun exposed areas such as cheeks, ears, forehead backs of the hands and lower legs. They often enlarge more rapidly than BCCs.

Early forms appear as scaly flat areas that may also resemble eczema.

SCC are particularly dangerous when they occur on the lip and must be diagnosed and removed early. Any crust, ulcer or thickened area on the lip that does not heal within 4 weeks should be checked.

You should see your doctor if you notice any of the following:

• A new red or skin coloured lump in the skin.
• An apparent patch of eczema that persists and doesn't respond to treatment
• A new scar in the skin without obvious cause
• Any spot in the skin that crusts or bleeds easily
• Any crust, lump or ulcer on the lip that does not heal within 4 weeks

These are not actually skin cancers but a small proportion may turn into squamous cell carcinomas (SCC). They are a marker of risk for skin cancer. Fifty percent of the population of New South Wales over the age of 40 has them. They appear as scaly red areas on sun exposed areas. Unlike SCC they do not have the deeper lumpy nature. Treatment is by liquid nitrogen freezing or for extensive sunspots, Efudix cream, available from specialists.

Superficial BCC can easily be mistaken for a patch of eczema:

Nodular BCCs appear translucent and pearly:

Infiltrating BCCs are often subtle, with an ill-defined thickening or scarring of the skin without apparent cause:

SCC appear as thickened raised areas of skin with scaly crusted tops. SCC on the lip can be particularly dangerous:

The following image shows precancerous spots. They indicate sun damage: