What are non-melanoma skin cancers?
There are two main types: basal cell carcinoma and squamous cell carcinoma. A third group of lesions called keratinocyte dysplasias includes solar keratosis, Bowenoid keratosis and squamous cell carcinoma in-situ (Bowen’s disease). These are not invasive cancers, however may require treatment as some may develop into non-melanoma skin cancers.
Basal cell carcinoma (BCC)
BCC accounts for about 70% of non-melanoma skin cancers. It begins in the lower layer of the epidermis (top, outer layer of the skin). It can appear anywhere on the body but most commonly develops on parts of the body that receive high or intermittent sun exposure (head, face, neck, shoulders and back).
Basal cell carcinoma symptoms
BCC often has no symptoms and tends to grow slowly without spreading to other parts of the body.
Symptoms of BCC may include:
- a pearly lump
- a scaly, dry area that is shiny and pale or bright pink in colour.
Squamous cell carcinoma (SCC)
SCC accounts for about 30% of non-melanoma skin cancers. It begins in the upper layer of the epidermis and usually appears where the skin has had most exposure to the sun (head, neck, hands, forearms and lower legs). SCC generally grows quickly over weeks or months.
Squamous cell carcinoma symptoms
Symptoms of SCC may include:
- thickened red, scaly spot
- rapidly growing lump
- looks like a sore that has not healed
- may be tender to touch.
Causes of non-melanoma skin cancers
Skin cancer occurs when skin cells are damaged, for example, by overexposure to ultraviolet (UV) radiation from the sun. Between 95% and 99% of skin cancers in Australia are caused by exposure to the sun. The risk of skin cancer is increased for people who have:
- increased numbers of unusual moles (dysplastic naevi)
- fair skin, a tendency to burn rather than tan, freckles, light eye colour, light or red hair colour
- had a previous skin cancer.
Screening for non-melanoma skin cancers
There is no organised screening program for non-melanoma skin cancers. People should be aware of their skin and see a doctor if there are any significant changes, such as changes to moles, freckles and spots on the skin.
Diagnosis for non-melanoma skin cancers
If you notice any significant changes to your skin, your doctor will examine you. Diagnosis is by biopsy (removal of a small sample of tissue for examination under a microscope).
Treatment for non-melanoma skin cancers
The type of treatment depends on the type and size of the cancer and where it is located.
Staging
Usually a biopsy is sufficient to determine the stage of a non-melanoma skin cancer. In cases of squamous cell carcinoma, lymph nodes may be examined to see if the cancer has spread. The staging system used is the TNM system, which describes the stage of the cancer from stage I to stage IV.
Biopsy
Sometimes, all the cancer is removed with the biopsy and in this case it will be the only treatment received.
Surgery
This is the most common treatment. Non-melanoma skin cancers are almost always removed (usually under a local anaesthetic). In more advanced skin cancers, some of the surrounding tissue may also be removed to make sure that all of the cancerous cells have been taken.
Chemotherapy
Most non-melanoma cancer can be treated with chemotherapy that is applied to the skin as an ointment or cream. This type of treatment is for skin cancers that affect the top layer of skin.
Radiotherapy
Radiotherapy is generally used to treat skin cancers in areas near the eyes or on the nose or forehead, which are difficult to treat with surgery. This treatment uses x-rays to kill cancer cells.
Other treatments
Non-melanoma cancer can also be removed by cryotherapy (using liquid nitrogen to rapidly freeze the cancer off), curettage (scraping) or cautery (burning).
Prognosis for non-melanoma skin cancers
An individual's prognosis depends on the type and stage of cancer, as well as their age and general health at the time of diagnosis. The majority of basal cell carcinoma cancers are successfully treated.
Preventing non-melanoma skin cancers
Avoid sunburn by minimising sun exposure especially in the middle of the day when UV levels are most intense. Seek shade, wear a hat that covers the head, neck and ears, wear sun protective clothing and close-fitting sunglasses, and wear an SPF30+ sunscreen. Avoid using solariums (tanning salons).