Photodynamic Therapy as Mesothelioma Treatment: An In-Depth Look

Malignant mesothelioma is an extremely aggressive form of cancer that is caused by exposure to asbestos. Its latency period—the time from first asbestos exposure to showing signs and symptoms and being diagnosed—is very long compared with other cancer types. People with mesothelioma may not become aware of their cancer until 25 or more years have passed since their first exposure to asbestos-containing materials. Mesothelioma grows and spreads with devastating speed, and unless the cancer is caught very early on and treated immediately, it can shorten life expectancy in its victims significantly.

What is Photodynamic Therapy?

Photodynamic therapy (PDT) is a newly-approved treatment for certain types of cancer, including malignant mesothelioma. In PDT, a patient is injected with a drug that is specially designed to travel to the area in the body where the cancer is, and to remain inert until activated by light. Then, the patient has a small, light-emitting device inserted into the region where his or her tumors are, and the light is activated—thus activating the cancer-fighting drugs right in the area they are needed.

What Are the Benefits to Photodynamic Therapy?

PDT is minimally invasive by itself, and can be performed in an outpatient setting so that the patient can go home right after treatment rather than recuperating for days or even weeks in a hospital setting (as is the case with surgery). It is also a very precisely targeted method of treatment, so the cancer is affected without unnecessary damage being done to healthy tissues surrounding the tumor.

Financially speaking, PDT is very cost effective, as it costs far less than other, riskier, more-invasive treatments such as surgery. Due to its non-invasive and comparably non-hazardous nature, PDT is a treatment which can be repeated again and again, with little down time in between treatment sessions. Side effects are also quite minimally reported, and those that are (such as sun sensitivity for up to a month post-treatment) are relatively non-hazardous and do not tend to interfere with quality of life.

Are There Risks Involved with Photodynamic Therapy?

PDT is not entirely without side effects. Since it can induce photosensitivity of the skin and the eyes, sunburn and pain in the eyes when in a well-lit area for the month following treatment is a common side effect of PDT. Also, if the light used to activate the cancer-attacking drugs should penetrate nearby non-cancerous tissues in the body, those tissues may become inflamed and cause some discomfort for the person undergoing treatment. In pleural mesothelioma, this may mean coughing and difficulty breathing for a short time following treatment. For peritoneal mesothelioma, this sometimes manifests as abdominal pain or a burning sensation near the area that was targeted during treatment.

Photodynamic Therapy vs. Other Treatment Methods

PDT has many benefits and few drawbacks as compared with other treatment methods typically used against mesothelioma. Here is a comparison between PDT and several other common cancer treatments used for malignant mesothelioma.

Surgery

PDT is far less invasive and less expensive than surgery, and requires far less down time following treatment than surgery. Surgery also typically leaves scarring, and carries with it many risks—the more invasive, the greater the risks—whereas PDT treatment rarely leaves scars and, due to its relatively non-invasive nature, can be carried out in an outpatient setting rather than a hospital setting.

Radiation Therapy

While PDT has a low incidence of unpleasant side effects, radiation therapy carries with it a long list of uncomfortable side effects. PDT is also very precisely targeted: it treats the area where the cancer is, leaving surrounding healthy tissues mostly intact and untouched, whereas radiation therapy has a deeper reach, and can have a negative impact on the health of tissues surround the area with the tumor. In other words, good, healthy tissue may be sacrificed during the course of radiation treatment.

Chemotherapy

Traditional chemotherapy involves administering drugs to patients—drugs that act systemically. Unfortunately, this can cause a variety of side effects and have an impact on the patient’s entire body and sense of well-being. With PDT, the action of the drugs is mostly limited to the treatment area, so the cancer itself is attacked without the entire body being under attack. While chemotherapy patients often report such side effects as severe nausea, side effects are rare and comparably mild with PDT.

Who Are the Best Candidates for Photodynamic Therapy?

PDT is most effective when it is used in cancers that are still localized—that is, those tumors which have been caught early on and have not yet spread out to other parts of the body. People diagnosed in Stage I or Stage II may be good candidates for PDT.