Levertumoren: PDT - Photodynamische therapie toont mooi effect bij 5 patiënten met levermetastases vanuit darmkanker.

In de reguliere oncologie/radiologie wordt veel onderzoek gedaan naar en geëxperimenteerd met PDT - fotodynamische therapie (laserlicht). In Duitsland hebben ze 5 patiënten met levermetastases vanuit darmkanker en na het falen van de chemo behandeld met PDT en een chemische component - SQN 400 - als fotosensitizer gebruikt die de werking en het effect van het laserlicht versterkt. Zie hieronder het studieverslag. Een follow-up na drie maanden toonde dat bij drie patiënten de tumoren volledig waren verdwenen en bij de andere twee leek iets van het tumorweefsel achter te zijn blijven. Maar kan natuurlijk dan alsnog gemakkelijk een keer herhaald worden. De PDT werd toegepast door een holle naald rechtstreeks bij de tumoren en niet gewoon als lichtstraling over het hele lichaam. Wel werd ook hier infrarood licht gebruikt en was chlorofyl de belangrijkste component, die ook bij spirulina de belangrijkste component is. Hierbij het studieverslag.

Pilot Study Suggests Photodynamic Therapy Effective for Liver Metastases
By W. A. Thomasson

CHICAGO, IL -- December 5, 2002 -- Photodynamic therapy may be effective for treatment of liver tumours, according to results from a small study presented here December 3 at the annual meeting of the Radiological Society of North America.

Photodynamic therapy involves systemic injection of the photosensitiser that is then activated locally by laser light. The activated photosensitizer creates singlet oxygen that destroys surrounding tissue. Photodynamic therapy is an established therapy for superficial cancers and, more recently, those that are endoscopically accessible. It is only the recent development of new catheter systems and fibers, however, that has allowed application to solid tumours.

Researchers led by Kerstin Engelmann, MD, of Johann Wolfgang Goethe University in Frankfurt-am-Main, Germany, treated five patients using the photosensitiser SQN 400. All had colorectal cancers metastatic to the liver that were in locations accessible to the laser catheter. All had previously been treated with chemotherapy; one had also had radiation therapy and one a hemihepatectomy.

Laser exposure, using a newly developed system, was five days after photosensitiser injection. Three patients had four treatments at a photosensitiser dose of 6 mg/kg, the other two had seven treatments at 3 mg/kg. Dr. Engelmann reported that follow-up examination at three months showed complete destruction of the cancer in three patients, with signs of residual tumor in two.

Photodynamic therapy requires patients to avoid bright electrical light for several days and direct sunlight for approximately four weeks. Since the photosensitiser is a vascular irritant, it is no surprise that three patients reported local pain during injection, with one reporting it as spreading to the shoulder. Several patients also experienced minor burns.

This pilot study establishes that the procedure is technically feasible and can eliminate metastatic liver tumors in some patients. Further study will be needed, however, both to determine optimal technical parameters and to establish the procedure's overall place in therapy of liver tumors.

References:

Thomasson WA. Pilot study suggests photodynamic therapy effective for liver metastases. Doctor's Guide News, December 5, 2002.

Rovers JP et al. In vivo photodynamic characteristics of meta-tetrahydroxyphenyl bacteriochlorin. Paper 171. Presented at the American Society for Photobiology 28th
Annual Meeting, San Francisco, CA, July 2, 2000.

levertumoren, PDT