Photodynamic therapy for mesothelioma

Abstract

Multiple trials of traditional cancer therapies for malignant pleural mesothelioma (including surgery, radiation therapy, and chemotherapy) have not convincingly demonstrated that any one treatment is superior to supportive care alone. Although there have been reports of long-term survivors who were treated with aggressive surgery combined with radiation and aggressive multi-agent chemotherapeutic regimens, these patient populations are highly selected and results cannot be generalized to a larger population. Despite attempts to use aggressive multimodality therapies, disease recurs in most patients. Local failure in particular is a large part of the natural history of mesothelioma, especially after surgery alone. Therefore, one of the major considerations in the development of new treatments is the inclusion of aggressive local therapies. Photodynamic therapy (PDT), a local treatment modality, is being evaluated as an adjuvant therapy to surgical resection. Clinical use of PDT requires the use of a photosensitizing agent and light of a wavelength specific to the absorption characteristics of the sensitizer in the presence of oxygen. The treatment effect of PDT is superficial, mostly because of the limited depth of light absorption in tissues. Therefore, it is theoretically an ideal treatment for tissue surfaces and body cavities after surgical debulking procedures. One theoretical advantage of PDT is that it can be used to treat the lung surface after a pleurectomy; therefore, patients may be treated with a pleurectomy rather than with an extrapleural pneumonectomy. Several studies have evaluated the efficacy of PDT in the treatment of mesothelioma. Clinical studies have not proven convincingly that the use of PDT is superior to the use of other adjuvant therapies or to surgery alone. The advent of newer photosensitizers and improved laser technology has led to a renewed interest in evaluating PDT. Additional studies are necessary to determine the role of PDT in the treatment of mesothelioma.

Photodynamic therapy of cancer: An update

“…Due to a limited light penetration through tissues the depth of tumor destruction ranges from few millimeters up to one centimeter. This apparent disadvantage can be favorably exploited in the treatment of superficial diseases, such as premalignant conditions (mucous dysplasia, actinic keratosis), carcinoma in situ or superficial tumors (such as malignant pleural mesothelioma 118 or intraperitoneal disseminated carcinomatosis 119-120 ). Moreover, PDT can be used supplemental to surgery, to irradiate tumor bed and increase the probability of long-term local disease control.…”

Light Sources and Dosimetry Techniques for Photodynamic Therapy

“…Its use for treatment of age-related macular degeneration (3)(4)(5), actinic keratosis (6,7), esophageal cancers (8,9), and non-small cell lung cancer (10,11) has been approved by the FDA. The use of PDT in pre-clinical studies and clinical trials for skin (12)(13)(14), bladder (15), prostate (16), brain (17,18), and head and neck cancers (19)(20)(21)(22), as well as malignant mesothelioma (23)(24)(25) and gynecologic disease (26) have been reported. In contrast with chemotherapy, PDT is a highly localized treatment technique that can spare healthy cells.…”

The clinical impact of photodynamic therapy in thoracic surgery

“…Several reports proposed that MPM obviously responds to PDT [12][13][14][15][16][17][18][19][20]. Therefore, it would be more efficient to perform PDT in addition to tumor debulking or pleuropneumonectomy in order to improve local control of further tumor growth.…”

“…Because of this lack of sufficient treatment options for MPM [10,11], it is a challenge to establish further novel adjunctive therapeutical approaches which may help to improve the poor prognosis of patients suffering from MPM. The efficiency of PDT as a supportive treatment option in case of MPM has been described and established in several clinical studies [12][13][14][15][16][17][18][19][20].…”