UK CANCER RESEARCH Photodynamic therapy
Photodynamic therapy (PDT) is also called light activating treatment. It kills cancer cells by using a combination of a light sensitising drug and a very bright light.
PDT can completely cure some early food pipe (oesophageal) cancers. But sometimes you need other treatments too, such as surgery or chemotherapy.
PDT can shrink advanced cancers that are blocking the food pipe. Then you can swallow more easily.
You have the treatment in hospital in the endoscopy department or x-ray department. It usually takes about 30 minutes.
What is photodynamic therapy (PDT)?
Photodynamic therapy (PDT) is also called:
- photoradiation therapy
- phototherapy
- photochemotherapy
PDT combines a drug that makes cells sensitive to light with exposure to a particular type of light. The drug is called a photosensitiser or photosensitising agent.
There are different types of sensitising drugs and each is activated by light of a specific wavelength. The type of photosensitiser and light wavelength you have depends on where the cancer is in your body.
How PDT works
When the sensitising drugs are exposed to their particular light, they produce a type of oxygen that kills nearby cells.
PDT directly kills cancer cells, but doctors think it also acts in other ways to shrink or destroy tumours. The sensitising drug may damage blood vessels in the tumour, and stop it from receiving nutrients that it needs. PDT may also trigger the immune system to attack the cancer cells.
Before your treatment
Your doctor or specialist nurse explains what happens and how they do the treatment. They ask you to sign a consent form saying that you agree to have the procedure. You can ask them any questions that you have. Tell them about any medicines you are taking.
You have a medicine that makes cells sensitive to light and then you go home. You might have the medicine as a liquid that you swallow or you might have it as an injection through a small tube in a vein in the back of your hand.
The light sensitising drug circulates throughout your body. So your skin and eyes become sensitive to light. You need to avoid bright sunlight and bright indoor light.
When you go outside, you must cover all your skin and wear sunglasses.
Two to three days later, you go to the endoscopy department at the hospital.
Having treatment
You shouldn’t eat or drink anything except water for 4 to 6 hours before the treatment. You can drink water until 2 hours beforehand.
A nurse puts a small tube called a cannula into a vein in the back of your hand. They go with you to the endoscopy or x-ray department.
The doctor or nurse injects medicine to make you sleepy into the cannula. Or you might have a general anaesthetic.
When you’re very sleepy or asleep your doctor gently puts a long flexible tube called an endoscope into your food pipe. The tube has a small camera on the end so they can see the cancer. They position the end of the tube close to the tumour and shine a low power laser light at it.
The light activates the drug in the cancer cells.
Your doctor takes the endoscopy tube out.
After treatment
You stay in the endoscopy department or x-ray department until the sedation or anaesthetic wears off. You might wear an oxygen mask for a short time. A nurse then takes you back to your ward. You can usually go home that evening.