Photodynamic therapy of oral cancer: photosensitisation with systemic aminolaevulinic acid.
Photodynamic therapy with intravenous photosensitising drugs has been shown to be effective in the ablation of superficial cancers, but long-lasting photosensitivity is a serious disadvantage. Similar photosensitivity is a feature of certain types of porphyria. We present the first report of tumour necrosis brought about by photodynamic activation of a temporary endogenous porphyrin accumulation, after an oral dose of the haem precursor, 5-aminolaevulinic acid. In 4 patients, quantitative fluorescence microscopy showed that accumulation of the photoactive intermediate protoporphyrin IX peaked after 4-6 h in 4 oral cavity squamous cell carcinomas, returning to background in 24 h. Irradiation with non-thermal red laser light caused tumour necrosis in 3 patients.
Grant
W E
WE
National Medical Laser Centre, University College London Medical School, UK.
Hopper
C
C
MacRobert
A J
AJ
Speight
P M
PM
Bown
S G
SG
D000284:Administration, Oral; D000622:Aminolevulinic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D005453:Fluorescence; D006801:Humans; D053685:Laser Therapy; D009062:Mouth Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D009336:Necrosis; D010166:Palliative Care; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D011524:Protoporphyrins / Q000096:biosynthesis
D017319:Photosensitizing Agents; D011524:Protoporphyrins; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX