Photodynamic therapy for malignant pleural mesothelioma: the future of treatment?

Our plain-English summary of Photodynamic therapy for malignant pleural mesothelioma: the future of treatment?, by J.S. Friedberg (Expert Review of Respiratory Medicine, 2011).

The study

• Author: J.S. Friedberg
• Journal: Expert Review of Respiratory Medicine
• Published: 2011;5(1):49-63
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant pleural mesothelioma is a deadly incurable cancer, with a median survival of approximately 9 months. The best available chemotherapy, arguably the standard of care, only yields a 40% response rate and an 11-week extension in median survival. Surgery, the modality most likely to be associated with prolonged remission, remains investigational and must always be combined with other modalities in an effort to treat the microscopic disease that will remain even after the most aggressive operations. One such modality, photodynamic therapy, is a light-based cancer treatment that has features making it particularly well suited as a component of a surgery-based multimodal treatment plan. Utilizing intraoperative photodynamic therapy has enabled development of a less drastic surgical procedure that is also yielding some encouraging survival results. A unique aspect of photodynamic therapy is its stimulation of a tumor-directed immune response, a feature that offers promise for designing future treatments.

In plain English

This is a perspective article, an opinion-based review by a University of Pennsylvania thoracic surgeon, on photodynamic therapy (PDT) given during surgery for malignant pleural mesothelioma. PDT is a light-activated cancer treatment. The article does not discuss asbestos. The author described the group's own small retrospective comparison of 28 patients treated with surgery and PDT. Of these, 14 had a lung-removing operation (modified extrapleural pneumonectomy) and 14 had a lung-sparing radical pleurectomy. Of the 28, 23 had stage III or IV disease. Disease-free survival was 22.8 months after pleurectomy and 7.2 months after pneumonectomy, a difference that was not statistically significant. Overall survival differed significantly (p = 0.009). At the time of writing, median survival was 11.8 months in the pneumonectomy group and had not been reached in the pleurectomy group. The author cautioned that the study was small and retrospective, and that both PDT's therapeutic value in this setting and the group's observed immune effect on recurrence were unproven. The author concluded that the results were highly suggestive that lung-sparing surgery with PDT was positively impacting survival in these patients.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Perspective (opinion-based review) article. It includes a brief report of the author's group's own small retrospective comparison of two surgical approaches combined with intraoperative photodynamic therapy.
• Who was studied: 28 patients with malignant pleural mesothelioma treated by the author's group at the University of Pennsylvania (dates not given). 14 had modified extrapleural pneumonectomy (MEPP) and 14 had radical pleurectomy (RP). 23 of the 28 (82%) were AJCC stage III or IV. Nonepithelial subtype was more common in the MEPP group (8 of 14) than in the RP group (3 of 14), a difference that was not statistically significant (p = 0.12).
• Exposure: No asbestos exposure is discussed. The treatment studied was surgery (lung-removing MEPP or lung-sparing RP) plus intraoperative PDT. The light-sensitizing drug was porfimer sodium at 2 mg/kg given 24 hours before surgery, activated by 630 nm laser light delivered until each of seven detectors measured 60 J/cm2.
• Main results:
  • Disease-free survival was 22.8 months in the RP group and 7.2 months in the MEPP group. This difference was not statistically significant.
  • Overall survival differed significantly between the groups (p = 0.009).
  • At the analysis presented at a 2010 meeting, median overall survival was 8.4 months in the MEPP group. In the RP group, median survival had not been reached at a median follow-up of 25.2 months.
  • At the time of writing, with a mean and median follow-up of 27 months, median survival was 11.8 months in the MEPP group and had not yet been reached in the RP group.
  • In the group's earlier Phase I trial, 3 of the 14 patients (21%) treated at the maximum tolerated dose relapsed with an isolated local recurrence.
  • The group reported no perforations in well over 100 intrapleural PDT cases. In its Phase I dose-escalation trial, a fatal systemic inflammatory response was the dose-limiting toxicity.
• The authors' conclusion: The author concluded that, despite the study's small size and retrospective nature, the results were highly suggestive that the lung-sparing procedure with intraoperative PDT was positively impacting survival in this mesothelioma population.
• Limitations the authors state:
  • The comparison was a small retrospective study.
  • The Phase I trial was not designed or powered to examine local control with lung-sparing surgery.
  • PDT has not been proven to be of therapeutic value in this setting.
  • The group's observation that PDT appears to have an immunologic effect that improves the pattern of recurrence in its patients is unproven.
  • The evidence that the residual PDT-treated disease in these patients acts as an autologous tumor vaccine is circumstantial.
  • One patient's strong response to gene therapy after RP and PDT is an isolated finding of unclear significance.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Median Survival, Chemotherapy.

Related studies

• Real-time light dosimetry for intra-cavity photodynamic therapy: Application for pleural mesothelioma treatment — N. Betrouni, C. Munck, et al. (2017)
• Intrapleural Photodynamic Therapy for Mesothelioma: What Place and Which Future? — C. Munck, S.R. Mordon, et al. (2015)
• Photodynamic therapy and the evolution of a lung-sparing surgical treatment for mesothelioma — J.S. Friedberg, R. Mick, et al. (2011)
• A Novel Prospective Study Assessing the Combination of Photodynamic Therapy and Proton Radiation Therapy: Safety and Outcomes When Treating Malignant Pleural Mesothelioma — S.R. Rice, Y.R. Li, et al. (2019)
• Photodynamic therapy for lung cancer and malignant pleural mesothelioma — C.B. Simone, K.A. Cengel (2014)
• Photodynamic therapy as adjuvant therapy in surgically treated pleural malignancies — P. Baas, L. Murrer, et al. (1997)

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