ABSTRACT
The aim of this review was to describe briefly the mechanism and history of photodynamic therapy (PDT). The achieved preclinical and clinical results in Rotterdam are discussed in the light of a search to optimize aminolevulinic acid-photodynamic therapy (ALA-PDT). As the incidence of skin cancer is rising, an optimized treatment in non-melanoma skin cancer is needed.
Subject(s)
Aminolevulinic Acid/therapeutic use , Photochemotherapy , Photosensitizing Agents/therapeutic use , Skin Neoplasms/drug therapy , Clinical Trials as Topic , Drug Evaluation, Preclinical , HumansABSTRACT
Tumor hypoxia is generally considered to be related to aggressive behaviour of a tumor. As in lung cancer direct determination of oxygenation is difficult, hypoxia-related proteins have been studied. A number of studies on these proteins show different results and the usefulness of these protein expressions remains questionable. In this article, we relate one of these hypoxia-related proteins (hypoxia-inducible factor, HIF1a) to a direct in vivo spectroscopic measurement of tumor blood saturation performed during bronchoscopy. Seventeen samples from malignancies and non-malignant tissues were studied. Microvascular saturation levels in the no malignancy group equalled 87+/-11.5% (range 71-100%) and in the malignant group 43+/-21% (range 6-63%). This difference was statistically significant (p<0.0002). There was a significant difference in the spectroscopically determined saturations between the biopsies with negative expression of HIF1a and the biopsies with positive expression of HIF1a (p<0.005). From these data, it can be concluded that HIF1a expression is related to a low microvascular blood saturation as determined in vivo by optical spectroscopy. This study may lead to a better acceptance of the usage of different techniques to establish hypoxia in order to study the effect of hypoxia on therapeutic interventions and prognosis of lung cancer.
