Photodynamic therapy in the treatment of intracranial gliomas: A review of current practice and considerations for future clinical directions

Abstract

Invasive grade III and IV malignant gliomas remain di±cult to treat with a typical survival time post-diagnosis hovering around 16 months with only minor extension thereof seen in the past decade, whereas some improvements have been obtained towards¯ve-year survival rates for which completeness of resection is a prerequisite. Optical techniques such as°uorescence guided resection (FGR) and photodynamic therapy (PDT) are promising adjuvant techniques to increase the tumor volume reduction fraction. PDT has been used in combination with surgical resection or alternatively as standalone treatment strategy with some success in extending the median survival time of patients compared to surgery alone and the current standard of care. This document reviews the outcome of past clinical trials and highlights the general shift in PDT therapeutic approaches. It also looks at the current approaches for interstitial PDT and research options into increasing PDT's glioma treatment e±cacy through exploiting both physical and biological-based approaches to maximize PDT selectivity and therapeutic index, particularly in brain adjacent to tumor (BAT). Potential reasons for failing to demonstrate a signi¯cant survival advantage in prior PDT clinical trials will become evident in light of the improved understanding of glioma biology and PDT dosimetry.

Polyacrylamide gel substrates that simulate the mechanical stiffness of normal and malignant neuronal tissues increase protoporphyin IX synthesis in glioma cells

“…1,2 A considerable number of clinical trials have been conducted with some very promising results for hematoporphyrin derivative, 3 aminolevulinic acid (ALA)-protoporphyrin IX (PPIX), 4,5 and talaporfin 6 mediated PDT. 1,2 A considerable number of clinical trials have been conducted with some very promising results for hematoporphyrin derivative, 3 aminolevulinic acid (ALA)-protoporphyrin IX (PPIX), 4,5 and talaporfin 6 mediated PDT.…”

Acridine Orange as a Novel Photosensitizer for Photodynamic Therapy in Glioblastoma

“…Most photosensitizing agents are injected intravenously, with the therapeutic light applied directly to the tumor resection bed. 51,52 Studies have shown that topical application of photosensitizing agents, such as in dermatologic applications, is also effective. 34 Fluid-filled balloons that distribute the light to the cavity walls have been studied to evenly distribute the therapeutic light throughout.…”

Editorial

“…The results clearly show the correlation between the bioluminescence-based PDT response and the volume-averaged Since PDT is inevitably subject to intrinsic cancer resistance at the cellular and molecular levels via drug e®lux, hypoxia, levels of pigmentation and repair mechanisms, Huang et al in Fuzhou, China review the recent progress in understanding the interaction between multidrug resistance (MDR) transporters and PS uptake. 6 In addition, emerging strategies are discussed to overcome such resistance, including the use of MDR transport inhibitors, anti-vascular PDT, photochemical internalization, intratumoral injection of PS, multifunctional PS nanocarriers and enhancing the antitumor immunity. These strategies aim to make anticancer PDT more e®ective in the clinic and so gain greater acceptance into mainstream medicine.…”