PDT may be used for early-stage cancers of the head and neck to try to cure the cancer. It is usually given as part of a clinical trial. PDT can also be used in advanced cancer to shrink the tumour and reduce symptoms.
First, you have the photosensitising drug as an injection through a small tube (cannula) inserted into a vein. This takes a few minutes and then the tube is removed.
You will have to wait up to four days before having the second stage of your treatment (when the light is directed at the cancer cells). Your doctor will tell you when you need to come back to the hospital this.
Generally, only one treatment is given, although some people need a second treatment a few weeks later.
Possible side effects
Sensitivity to light
Although the photosensitising drugs are mostly taken up by the cancer cells and are concentrated there, they can also make your ordinary skin cells or your eyes highly sensitive to light. This is known as photosensitivity. How long this lasts will vary, depending on which drug is used.
The drug temoporfin (Foscan®) is commonly used to treat head and neck cancers. It can make you sensitive to direct sunlight for up to a month. During this period, you’ll be given specific instructions from your hospital team about protecting yourself from sunlight and bright indoor lighting. You will need to follow these instructions carefully to avoid burning your skin.
Your hospital team will give you advice on using lights inside your home, as well as other ways to avoid or reduce your exposure to strong light sources. Strong light sources include spotlights, fire, TV or even sunlight shining through a window. You will also be told when you are able to go outside and what clothing you should wear to protect your skin from sunlight.
You may be given a device called a portable light meter. You can use this to help measure the levels of light. If you are given a light meter, the staff who are treating you will explain how to use it.
When enough time has passed after your treatment, your doctor may ask you to check the photosensitivity of your skin. This usually involves exposing a small area of your skin to bright light for five minutes and assessing the reaction 24 hours later. Your doctor or nurse will explain this in more detail. As your skin becomes less sensitive to light, you will be given advice about gradually increasing the amount of light you're exposed to. You will also be given advice about any skin protection you need to continue with.
You should avoid having your eyes checked and light shone into your eyes while you're sensitive to light. This is because the area at the back of your eye (retina) will be more sensitive to light than usual.
PDT can cause pain in the tumour area. Your specialist nurse will explain how this may affect you and make sure that you have the right kind of painkillers. The amount of pain can vary, depending on where your tumour is and which photosensitising drug has been used.
Some people may only need simple painkillers such as aspirin or paracetamol. Others may need a stronger drug such as morphine. Let your doctor know if you have any pain.
Some photosensitising drugs can cause swelling in the treated area. This varies from one person to another. If you've had treatment in your mouth or throat, the swelling may make it difficult for you to swallow. The swelling is temporary but can be treated with steroid injections or drugs that help reduce inflammation. It's important to let your nurse or doctor know if swallowing becomes difficult.
Feeling sick (nausea)
Some people may feel sick, but this can be controlled with anti-sickness (anti-emetic) tablets.
PDT causes much less scarring than surgery. However, the amount of time it takes for areas treated withn for PDT-treated areas to heal can vary. It may be several weeks, depending on the area treated and how deeply the light has penetrated into the body’s tissues.