Skin cancer

Superficial skin cancers are the most common form of cancer affecting all Australians. They are divided into melanomas and non-melanoma skin cancers.

Radiotherapy alone is often used to treat superficial skin cancers that are not melanomas.

In special circumstances, following surgery, radiotherapy can be used to reduce the risk of skin cancers, including melanomas, recurring.

Please note that superficial radiotherapy (SXRT) is effective in treating most non-melanoma skin cancers, either as the primary treatment of the cancer or if it has been cut out, but not completely. The aim is cure with a good functional and cosmetic outcome in any circumstance.

Non-melanoma skin cancers 

Of those that are not melanomas, basal cell carcinomas (BCC) are the most common, representing 85% of all superficial skin cancers. Squamous cell carcinomas (SCC) are the next most common and considered more aggressive than BCCs as they tend to spread through the bloodstream and lymphatics.

Why do they develop?

Ultra-violet exposure from the sun is considered the primary risk factor. A genetic pre-disposition, fair skin and northern European descent are also considered risk factors.

Skin cancers can be hard to differentiate from benign sun spots (solar keratoses) and pre-cancerous conditions such as Bowen’s disease. It is important not to neglect skin spots that appear irregular, grow in size, ulcerate or that bleed. You should always check with your local doctor if you are concerned about a skin lesion. If they are unsure, they can refer you to a Dermatologist or Specialist Radiation Oncologist.

Diagnosis

Clinicians with experience can often tell whether a skin spot is cancerous or not by examining it. Some clinicians use a dermatoscope, which is also called “surface skin microscopy” as it enables a magnified view of the skin.

In order to confirm the diagnosis, your doctor may perform a punch biopsy, which is when a small circle (2 to 5mm) of the superficial skin is cut out under local anaesthetic and sent to a pathologist for microscopic evaluation. If the lesion is not too large, your doctor may perform an excisional biopsy, which is when the whole lesion is cut out and the wound stitched back up.

Treatment of Non-Melanoma Skin Cancers

Non-melanoma skin cancers can be cured in most instances if treated early and adequately enough.

Surgery is usually the most common form of treatment in younger patients. However, if the lesion is not cut out entirely (close or positive surgical margins) or the risk of it recurring is high because it is aggressive (grade 3) or exhibits invasion of nerve tissue (perineural invasion), then often radiotherapy is recommended as an adjunct treatment.

Superficial radiotherapy is of benefit also to (i) patients who cannot have surgery, (ii) if the skin cancer is large, requiring extensive surgery and grafting or (ii) if it is in an awkward position, such as the face, where surgery would be deforming. You can always request an opinion from a Radiation Oncologist. 

Radiotherapy for non-melanoma skin cancers

Superficial radiotherapy provides excellent cure rates for superficial skin cancers such as basal cell carcinomas and squamous cell carcinomas, as well as pre-cancerous conditions such as Bowen's disease (carcinoma in-situ) or recurrent sun spots that could turn into cancer.

The outcomes are equal to that of surgery with proven cure rates of 95% and higher, and often the cosmetic result is much better than surgery which may require skin grafts or leave deformities.

Treatment is quick, invisible and pain-free and usually conducted once a week over 4 to 6 weeks.

The advantage of superficial radiotherapy is that can be used for a number of different patients, who can't have other treatments, such as patients who:

1. Are medically unfit for surgery or too frail for a general anaesthetic.

2. Have multiple or widespread skin cancers, which would require major reconstructive surgery involving skin grafting.

3. Have reasons why they can't have surgery, including medications such as warfarin, which thins the blood, making surgery dangerous.

4. Require treatments to difficult areas, such as the head and neck region, where the risks of incomplete excision, damage to normal, important structures and poor cosmetic outcomes are extremely high.

5. Are at a very high risk of recurrence of the cancer following surgery alone, with risk factors for recurrence such as incomplete excision, tumours that are poorly differentiated (grade 3) or that invade nerve tissue (perineural invasion).

Side Effects

It results in very few side effects, which if they occur, consist of mild tiredness and a skin reaction, much like sunburn, which usually heals nicely. In the long term, the skin may become a little thinner and slightly scarred or pigmented when compared to the surrounding skin. 

It is extremely important to follow the skin care instructions provided, which help prevent severe skin reactions and long term complications. The more diligent and obsessive the patient is with moisturising the skin during radiotherapy, the better the cosmetic result generally. This part of the consultation has formed "my reading of the riot act" and stresses that self-care durign treatment is a full-time responsibility.