Photodynamic therapy for thoracic malignancies

Our plain-English summary of Photodynamic therapy for thoracic malignancies, by H.I. Pass, H. Pogrebniak (Seminars in Surgical Oncology, 1992).

The study

• Authors: H.I. Pass, H. Pogrebniak
• Journal: Seminars in Surgical Oncology
• Published: 1992;8(4):217-25
• Type of article: Review
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Photodynamic therapy (PDT) is an experimental form of cancer therapy which employs photoactivation of a sensitizing chemical by light of a given wavelength via the production of toxic oxygen species. PDT causes local destruction of cancer, and relies on a therapeutic index between normal and malignant tissue since the latter seems to selectively retain the sensitizer. PDT has both direct tumoricidal effects as well as indirect effects on tumor vasculature causing an early hemorrhagic necrosis of tissue. The treatment has been used for the treatment of endobronchial obstruction by primary and metastatic tumors. Most recently, trials are being performed to evaluate this therapy as a surgical adjunct in the treatment of pleural malignancies such as mesothelioma.

In plain English

This article was a review of photodynamic therapy (PDT), which the authors described as an experimental cancer treatment. In PDT, a light-sensitizing drug (Photofrin II) is activated by red laser light in the presence of oxygen. The article did not report a new study of its own and did not discuss asbestos. The review summarized published results of PDT for lung cancer blocking the airways. In one earlier series of 10 patients cited by the authors, 80% were objectively improved and 20% had a histologic complete response. The review also covered detecting and treating early lung cancer, and complications, most commonly skin sensitivity to sunlight. For pleural malignancies, including malignant pleural mesothelioma, the authors described an ongoing Phase I study giving PDT inside the chest after surgery to remove as much tumor as possible. No results from that study were reported. The authors concluded that for such patients, whose curative surgical options were close to zero with standard treatment, an add-on treatment given during surgery that might achieve local control could be a first step toward improving survival.

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: Narrative review of photodynamic therapy for thoracic malignancies; summarizes published results from other studies rather than reporting new data
• Who was studied: Patients with thoracic cancers as described in the reviewed literature: lung cancer causing endobronchial obstruction, early stage or occult lung cancer, and pleural malignancies (isolated malignant pleural effusions, Stage IIIB lung cancer, malignant pleural mesothelioma). Table I lists 13 published series of bronchial obstruction, ranging from 7 to 236 patients.
• Exposure: Treatment, not asbestos exposure: photodynamic therapy with the sensitizer Photofrin II, generally 2 mg/kg intravenously 48 to 72 hours before illumination with 630 nm laser light
• Main results:
  • In an earlier series of 10 patients with endobronchial lesions (Pass et al., reference 6, cited in this review), treated with 2 mg/kg of sensitizer 72 hours before light, 80% of patients were objectively improved and the histologic complete response rate was 20%
  • The review reported that skin sensitization was the most common complication of endobronchial PDT and could be minimized by limiting sun exposure for at least 4 weeks
  • The review cited Balchum et al. as reporting 4 deaths, 2 of which occurred in patients treated with radiation therapy before PDT
  • In a cited study by Lam et al. using low-dose (0.25 mg/kg) Photofrin II to detect early lung cancer, the red-green fluorescence ratio was 0.9 to 1.8 in known normal areas and 4.8 (3.0 to 9.5) in biopsy-proven tumor areas
  • Japanese groups cited in the review reported on 40 cytology-positive-only early lung cancer patients, of whom 26 were treated without surgical resection. Those groups reported a 100% initial complete remission rate, with 3 (12%) late recurrences.
  • In a cited series of 13 patients with 14 carcinomas that responded completely to PDT, 11 of 13 had no local recurrence 3 to 53 months after treatment
  • For pleural malignancies including mesothelioma, a Phase I study was under way to define the maximal tolerated dose of PDT delivered to the chest cavity after maximum cytoreductive surgery. No results from it were reported.
• The authors' conclusion: The authors concluded that for patients with mesothelioma or Stage IIIB lung cancer, whose curative surgical options are close to zero with standard treatment, an intraoperative adjuvant that may obtain at least local control might be the first step toward improving survival
• Limitations the authors state:
  • The authors stated that PDT results for endobronchial lesions were limited by a lack of standardized protocols and of a clear definition of 'responses'
  • The authors stated that the benefits of PDT compared with Nd:Yag laser therapy were hard to quantitate

Topics

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

Medical terms in this study, explained in our Lexicon: Necrosis, Mesothelioma.

Related studies

• Intraoperative photodynamic therapy for malignant mesothelioma — H.I. Pass, Z. Tochner, et al. (1990)
• In vitro killing of human malignant mesothelioma by photodynamic therapy — S.M. Keller, D.D. Taylor, et al. (1990)
• Photodynamic therapy as adjuvant therapy in surgically treated pleural malignancies — P. Baas, L. Murrer, et al. (1997)
• Photodynamic therapy for mesothelioma — S.M. Hahn, R.P. Smith, et al. (2001)
• Chimeric Antigen Receptor (CAR) T-Cell Therapy for Thoracic Malignancies — S. Kiesgen, L. Chicaybam, et al. (2018)
• Proton therapy for thoracic malignancies: a review of oncologic outcomes — N.V. Patel, N.Y. Yu, et al. (2021)

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