The newest research on photodynamic therapy appears to confirm what multiple recent studies have found – that PDT is a safe and effective way to prolong survival in pleural mesothelioma patients after surgery.
A new meta-analysis of 16 studies on PDT for mesothelioma finds that the technique efficiently kills mesothelioma cells left behind after lung-sparing pleurectomy. For each of the studies, the French research team analyzed the specific PDT technique used, the level of toxicity, and the effect on survival in patients with malignant pleural mesothelioma.
“After two decades of clinical studies, intrapleural photodynamic therapy after surgical resection became a safe treatment that significantly improved the survival of patients,” reports lead researcher Camille Munck of Inserm in Loos, France.
Mesothelioma patients undergoing PDT get an injection of a photosensitizing drug several days before treatment. The most popular drug for this purpose is porfimer sodium (Photofrin), which has been recognized with orphan drug status by the FDA for its potential in treating mesothelioma. Mesothelioma cells absorb more of the photosensitizer and retain it longer than healthy cells, which is one of the reasons PDT produces fewer side effects than chemotherapy or radiation.
After mesothelioma tumor cells have had a few days to absorb the drug, doctors expose them to a specific wavelength of light by inserting fiber optic cables into the lungs. The light triggers the production of a highly reactive form of oxygen, killing the mesothelioma cells. Some research has suggested that PDT may also disrupt the blood supply that feeds mesothelioma tumors and may help trigger patients’ own anti-tumor immune responses. The technique is usually used in conjunction with surgery to remove the diseased pleura and other tissues in the chest at risk for mesothelioma.
A 2012 study of 97 pleural mesothelioma patients found that PDT after pleurectomy tripled survival times from around a year to more than 3 years. Other recent studies have produced encouraging results by combining PDT with chemotherapy, suggesting that the two treatments may work synergistically to fight mesothelioma.
Munck, Camille et al, “Intrapleural Photodynamic Therapy for Mesothelioma: What Place and Which Future?”, April 23, 2015, The Annals of Thoracic Surgery, Epub ahead of print
Friedberg, J et al, “Radical pleurectomy and photodynamic therapy for malignant pleural mesothelioma”, November 2012, Annals of Cardiothoracic Surgery
Photodynamic Therapy for Cancer, National Cancer Institute Website