Some types of lung cancer can be treated with a cancer-killing drug that works when it is combined with the power of light energy. This one-two punch is called photodynamic therapy, or PDT.
How Does Photodynamic Therapy Work?
If PDT is a good option for your lung cancer, here’s what you can expect:
Your doctor will inject a light-sensitive medication, known as a photosensitizer, into a vein (intravenously). The drug porfimer sodium (Photofrin) is widely used for this treatment.
Over the next 24-72 hours, all the cells in your body absorb the medicine. But the drug stays longer in cancer cells than in healthy cells.
Then, in the second part of the process, your doctor will insert a thin, lighted tube called a bronchoscope into your mouth and down to your lungs.
A certain wavelength of light, either from a laser or an LED, is then turned on inside this tube in the part of your lung that is being treated. Photofrin, for example, is activated by red light from a laser. The light triggers a reaction in the photosensitizing drug: It forms a special kind of oxygen molecule that kills the cancer cells.
PDT may help your cancer treatment in other ways. too. It can damage blood vessels in lung tumors, keeping them from getting the blood they need to grow. It can also trigger your immune system to attack cancer cells, even in other places in your body.
What Types of Lung Cancer Can PDT Treat?
Your doctor may recommend PDT if your lung cancer has grown into your airway, causing bleeding, trouble breathing, or a constant cough.
It might also be right for you if you have an early stage, non-small-cell cancer in certain areas of the lungs that the PDT tools can easily reach.
PDT can be a good option for these symptoms because:
- It can preserve your lung function.
- The treatment can be repeated, if necessary.
- It can be used in addition to other aspects of your cancer care, such as chemotherapy.
Benefits of Photodynamic Therapy
Some studies show that PDT can work as well as surgery or radiation therapy for some types of cancers and precancers.
Photofrin has been approved by the FDA for the treatment of early non-small-cell lung cancer since 1998. This medication does not accumulate in your healthy cells, so there is a low risk of DNA damage or other mutations.
Some other benefits:
- Less invasive than surgery
- No long-term side effects
- Can be very precisely targeted
- Usually done as an outpatient procedure
- Little scarring after the site heals
- Costs less than some other lung cancer treatments
Drawbacks of PDT
PDT can only treat areas that can be reached by a light source. The light can only pass through about one-third of an inch of tissue. Because it cannot reach very far into large tumors, it is not as helpful in treating them.
Some of the risks of this treatment for people with non-small-cell lung cancer are:
- Coughing up blood
- Shortness of breath
- Pneumonia or bronchitis
- Fever
What Side Effects Can I Expect?
A major side effect from the photosensitizer Photofrin is that your skin will be especially sensitive to light for as long as 4 to 6 weeks. You should avoid both direct sunlight and bright indoor light after your treatment.
Another photosensitizer, talaporfin sodium (Laserphyrin), is also effective for specific lung cancers. It has shown lower skin photosensitivity compared with Photofrin. It was approved in Japan in 2003.
What’s Ahead for PDT?
People have known about the healing properties of the sun and light for hundreds of years, going back to ancient Egypt, India, and China. Modern medicine has been combining the use of dyes and drugs with light illumination since the early 20th century.
Research continues to help more people with lung cancer with new forms of this therapy, such as:
- PDT drugs that can more precisely target tumor cells
- Drugs that can allow the treatment light to go deeper, reaching more cancer cells
- Combining other treatments, such as surgery and radiation therapy, with photodynamic therapy
