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Evaluation of photodynamic therapy near
functional brain tissue in patients with recurrent brain tumors
Schmidt MH, Meyer GA, Reichert KW, Cheng J, Krouwer HG, Ozker K, Whelan HT
Department of Neurosurgery University of Utah, Salt Lake City,
UT, USA.
Introduction. Photodynamic therapy (PDT) involves the selective retention
of a photosensitizer that upon activation with light mediates tumor cell
destruction via the production of singlet oxygen.
This study evaluates the toxicity of PDT and a new light-delivery device based
on light-emitting diode (LED) technology in selected patients with brain
tumors. Methods. Twenty patients with recurrent malignant brain tumors received 22
treatments with PDT. Sixteen tumors were supratentorial and four tumors were
infratentorial. Patients received IV Photofrin 24 h prior to light exposure
starting at 0.75 mg kg(-1). Laser and LED arrays were used to deliver 100 J
cm(-2) of light to the sensitized tumors. Fourteen patients received PDT with a
laser-balloon adapter, two via interstitial optical fibers and five patients had
LED based PDT. At the maximum Photofrin dose of 2.0 mg kg(-1) five patients
received laser-balloon adapter light and five patients received LED light. In
addition, three patients received LED light with 0.25 mg kg(-1) of Visudine, a
benzoporphyrin derivative (BPD). Quantitative analysis of toxicity and time to
progression was performed.
Results. Two patients had toxicity consisting of ataxia and facial weakness
after treatment with interstitial fibers. Escalating doses of Photofrin were
tolerated to the maximum dose of 2.0 mg kg(-1). BPD did not result in additional
toxicity. PDT in the posterior fossa or near eloquent brain was tolerated using
the LED or laser-balloon adapter. All patients had tumor responses as documented
by MRI scan and the mean time to tumor progression after PDT was 67 weeks.
Conclusion. PDT with LED balloon adapters (also tunable dye laser) has
acceptable toxicity in brain tumor patients. Future studies using more effective
photosensitizers could improve local recurrence control.
PMID: 15072468 [PubMed]
Source: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15072468
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