Photodynamic therapy

Researchers at the National Cancer Institute have investigates the use of intracavitary photodynamic therapy (PTD) as a supplementary treatment extrapleural  pneumonectomy, a highly invasive procedure involving the removal of the affected tissue and organs. Photodynamic therapy involves the administration of photosensitizers, light-sensitive molecules, which produce toxic singlet oxygen to when activated by a certain wavelength of light. Moderate success has been seen by using this therapy in lower risk patients with minimal tumor burden.

Phase I clinical trials are currently being conducted in the Netherlands and United States involving the use of a second generation photosensitizer which is thought to have better tissue penetration and a better singlet oxygen yield. A preliminary report by on the trial has shown the treatment to be relatively safe and effective. Three of the four patients involved in the trial were alive and showed no signs of a recurrent tumor after in a follow-up of 9-11 months. One patient died within 7 months of the procedure after developing a recurrence at the site and abdominal metastasis.

Immunotherapy

Immunotherapy is an effort to use the body’s immune system to combat cancerous cells and tumors. This strategy has been shown to be effective in the treatment of some forms of cancer but has shown very little promise when applied to mesothelioma. However, studies have shown that that high concentrations of proinflamatory cytokines may inhibit mesothelioma’s innate immune resistance.

This has theory has been supported in several clinical trials. The most impressive clinical results of cytokine therapy in mesothelioma have been with intrapleural delivery of a lymphokine produced by T lymphocytes. In a study of 89 patients, the overall response rate was 20%, with good tolerance of the cytokine. Eight stage I patients had confirmed complete remissions, and nine had partial responses with a greater than 50% reduction in tumor volume. Most of the significant responses were seen in patients with disease confined to the parietal and diaphragmatic pleura. Overall, patients with stage I disease had a response rate of 45%.      

Gene Therapy

Gene therapy is an extermly technical an cutting edge therapy that involves the injection of genes into a person’s affected cells in an effort to allow the mutated cell functionality to be replaced by that of healthy cell. This treatment method is still in its infancy but may over time offer the best chances for a mesothelioma cure. Mesothelioma is an attractive candidate for gene therapy due to the accessibility of the affected area and the lack of an effective treatment for the disease. A number of gene therapy trials are currently underway or have been scheduled. Those who have been diagnosed with mesothelioma and would like to be involved in a clinical trial for gene therapy should discuss this treatment option with their doctor.