Optimizing light dosimetry in photodynamic therapy of early stage carcinomas of the esophagus using fluorescence spectroscopy.
OBJECTIVE
Under standardized conditions (drug and light dose, timing), the result of the photodynamic therapy (PDT) of carcinomas of the esophagus with tetra(meta-hydroxyphenyl)chlorin (mTHPC) shows large variations between patients.


METHODS
Before patients underwent PDT treatment, the mTHPC level was measured in the lesion, the normal surrounding tissue, and the oral cavity, with an apparatus based on fluorescence spectroscopy.


RESULTS
The fluctuations in degree of tumor destruction between patients can be explained by individual variations in the mTHPC level in the mucosa of the esophagus. The patients showing the highest mTHPC fluorescence signal had also the highest response to PDT. Also, a correlation between the mTHPC level in the oral cavity and esophagus mucosa has been found.


CONCLUSIONS
PDT can be improved by measuring the mTHPC level in the esophagus or the oral cavity before treatment by fluorescence spectroscopy, and then by adjusting the light dose to be applied to the observed mTHPC level.
Braichotte
D R
DR
Institute of Environmental Engineering, Ecole Polytechnique Fédérale, Lausanne, Switzerland.
Savary
J F
JF
Monnier
P
P
van den Bergh
H E
HE
D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy*; D004938:Esophageal Neoplasms / Q000188:drug therapy*; D006801:Humans; D008652:Mesoporphyrins / Q000627:therapeutic use*; D010778:Photochemotherapy; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use*; D011874:Radiometry / Q000379:methods; D013050:Spectrometry, Fluorescence; D014226:Triazenes / Q000627:therapeutic use
D000970:Antineoplastic Agents; D008652:Mesoporphyrins; D011838:Radiation-Sensitizing Agents; D014226:Triazenes; C008848:1-phenyl-3,3-dimethyltriazene; C072269:temoporfin