PDT

Photodynamic therapy (PDT) is a treatment used mainly for superficial types of skin cancer. PDT is effective in treating actinic keratoses, in situ squamous cell carcinoma (Bowen disease), and superficial basal cell carcinomas. It may also be used for treatment of small, thin, low-risk nodular basal cell carcinomas

How PDT works

The cancer cells absorb the light sensitive drug. The doctor then applies light to the area where the cancer is. The light causes the drug to react and produce a type of oxygen that kills the nearby cells. 

When do you have PDT?

• some basal cell carcinomas (BCC’s)
• Bowen’s disease (squamous cell carcinoma in situ)
• actinic keratosis (solar keratosis)

For actinic keratosis you usually have one treatment. For basal cell carcinoma or Bowen’s disease you usually have two treatments 7 days apart. This is one cycle of treatment.

Your doctor will tell you what’s best for your situation. 

Before treatment

Before treatment, the doctor cleans the area and removes any crust or scale from the top of the skin cancer. 

They apply a light sensitizing cream to the skin cancer and the surrounding skin. You have a dressing on top to keep the cream in the right spot and stop it from rubbing off. 

You do this for at least 3 hours before the PDT treatment.   

During the treatment

After at least 3 hours you return to the treatment room cleans the cream away.

You’ll get a pair of sunglasses to wear during your treatment to protect your eyes from the light. 

The nurse then shines the light on the treatment area. The light kills any cells that have absorbed the drug. The light is usually red in colour. They shine the light for up to 20 minutes, depending on which light your doctor is using.

You might feel a stinging or burning sensation in the treatment area when the light is on.

You can have more than one skin cancer treated at a time. 

After treatment

A scab forms where you had the treatment, and you have a dressing in place to cover it. The doctor or nurse might also put a steroid cream on the treatment area. This helps to reduce any itching.

The dressing stays on for about 24 hours. Be careful not to bump or knock it. You need to also keep the dressing dry. 

The scab usually heals in about 3 weeks. 

The light sensitising drug makes the treated skin more sensitive to sunlight. Your doctor recommends that you wear sunscreen of SPF 50 or more for a least 48 hours.  

Side effects of PDT

After PDT, it is common to have some pain and discomfort for a few days. Taking regular painkillers such as paracetamol can help.

The treated area might have some inflammation. It may look pink, red and swollen. The site might also ooze or develop a crust. This should get better after a few days.