TREATING MESOTHELIOMA WITH PHOTODYNAMIC THERAPY

Photodynamic therapy (PDT) is an emerging treatment used for patients with pleural mesothelioma. It carries less side effects than other mesothelioma therapies and research has shown that it can improve life expectancy.

Photodynamic therapy is a novel, innovative treatment mesothelioma specialists are currently developing into an effective way to treat mesothelioma.

Essentially, the treatment involves the use of beams of light to activate mesothelioma-killing drugs. It has produced the most successful results when combined with surgery, such as a pleurectomy with decortication (P/D), as part of a multimodal course of treatment.

Photodynamic therapy is beneficial to mesothelioma patients because it carries less side effects than other forms of non-surgical treatment, like chemotherapy and radiation therapy.

Photodynamic therapy works by activating a light-sensitive drug, called a photosynthesizer, with light emitted from a laser.

The light-sensitive drug is typically given to a patient intravenously (via IV) and absorbed almost exclusively by mesothelioma cells. Light from a laser activates the cancer-killing properties of the photosynthesizer, which then releases oxygen and kills individual cancer cells. As the photosynthesizer kills more and more cancer cells, the growth of the cancer slows and the mesothelioma tumor shrinks.

Photodynamic therapy causes less side effects than other forms of non-surgical treatment because most of the photosynthesizer is absorbed by mesothelioma cells and not by healthy cells. As a result, when light from the laser is applied to the tumor, there is less of a chance that healthy cells near the tumor will be killed.

The laser that activates the light-sensitive drug is applied via an endoscope, a thin, flexible tube inserted through a small incision that’s typically made in the patient’s chest. Using an endoscope allows the surgeon to target the tumor more accurately. Additionally, patients can quickly recover from the procedure because the incision is small and minimally invasive.

Preparation for photodynamic therapy begins up to 3 days before the procedure itself. The photosynthesizer is usually injected a few days before the actual therapy begins to allow time for mesothelioma cells to absorb the light-sensitive drug.

The most common photosensitive drug used for photodynamic therapy is porfimer sodium, which is also known as Photofrin. Porfimer sodium is beneficial to patients because it has no effect on the body until it interacts with light given during treatment.

Giving a patient the photosynthesizer a few days before the procedure also helps cut down on side effects. Cancer cells retain the light-sensitive drug longer than normal cells, so the extra few days gives normal cells that absorbed some of the photosynthesizer time to get rid of it.

The procedure itself takes approximately 40 minutes, but can last less depending on the size of the mesothelioma tumor.

Although photodynamic therapy carries less side effects than chemotherapy or radiation therapy, patients should still be aware of a number of possible side effects.

The main cause of side effects resulting from photodynamic therapy is a phenomenon called photosensitivity.

After the procedure, some of the light-sensitive drug may stay collected in the patient’s healthy cells for several weeks. This raises the chances of photosensitivity, which occurs when the remaining photosynthesizer interacts with bright sunlight. The reaction between the drug and bright sunlight can cause the following symptoms, sometimes within a matter of minutes:

 

While patients should attempt to avoid direct sunlight, they should expose themselves to small amounts of ambient indoor light. This helps slowly breakdown the photosynthesizer and speeds up the recovery process, which usually lasts a minimum of 30 days.

Nausea and vomiting can also occur, though at a much less severe level than that caused by chemotherapy or radiation therapy.

Despite the fact that photodynamic therapy is an emerging mesothelioma treatment, it has shown promising results across a number of studies and is actively being developed in clinical trials.

In 2012, one study reported that, when paired with a pleurectomy, photodynamic therapy produced a survival time of over 3 and a half years (42 months). These results occurred in patients with epithelioid mesothelioma, the most common cellular type of the disease.

Clinical trials are currently testing the effectiveness of intraoperative photodynamic therapy. The benefit of using photodynamic therapy during surgery is that the laser light can be applied directly to tumors made more visually accessible by a large surgical incision.

Photodynamic therapy is a relatively new, exciting treatment being developed to fight pleural mesothelioma. More and more clinical trials are testing and refining the emerging therapy in combination with standard mesothelioma treatments, like the P/D.

If you’ve been diagnosed with pleural mesothelioma and would like to find out if photodynamic therapy can be an effective treatment for you, participate in a clinical trial.

Our Patient Help Team is partnered with a number of experienced specialists across the country and can help you get connected to the right clinical trial for your diagnosis. Speak to a member of our team and get more free information about photodynamic therapy and clinical trials.