Photodynamic Therapy

Photodynamic therapy (PDT) is a type of cancer treatment that involves the use of a drug called a photosensitizing agent, activated by being exposed to light, and used to destroy cancer cells.  The process is sometimes referred to as photoradiation, phototherapy, or photochemotherapy.  Photodynamic therapy is sometimes indicated for the treatment of mesothelioma.

How Does Photodynamic Therapy Work?

In PDT, the photosensitizing agent is either injected into the bloodstream of the patient or applied to the skin.  Once the drug is absorbed by the cancer cells – which usually takes 2-3 days – a light source is applied to the affected area.  The light then causes the drug to react to oxygen, forming a chemical that, in turn, kills the cancer cells.  Alternately, photodynamic therapy may also work by destroying the blood vessels that help keep cancer cells alive and by helping the immune system to attack the cancer.

Why Choose Photodynamic Therapy?

PTD can be targeted very precisely, allowing it to attack the cancer directly.  It is also less invasive than surgery and will result in much less scarring than other cancer therapies.  Unlike conventional radiation therapy, it may be used repeatedly in the same area without causing damage. 

Clinical trials are currently being conducted to measure the success of photodynamic therapy in combination with conventional cancer therapies.  This may be notably significant for mesothelioma patients as doctors are experimenting with a procedure that involves using PDT during surgery to help prevent the recurrence of cancer on large surface areas such as the pleura (lining of the lung) and the peritoneum (lining of the abdomen), common sites of spread for asbestos-related cancer.

Disadvantages and Side Effects

Photodynamic therapy can only treat areas that can be reached by light (on or just under the skin or in the lining of internal organs), so its use is limited.  It also cannot be used to treat extensive cancers that have already spread to many parts of the body.

If your doctor does recommend photodynamic therapy for treatment of mesothelioma, be aware that the drugs used may cause extreme sensitivity to light, so you’ll need to carefully follow your doctor’s recommended precautions.