Sensitization and photodynamic therapy (PDT) of gastrointestinal tumors with 5-aminolaevulinic acid (ALA) induced protoporphyrin IX (PPIX). A pilot study.
5-Aminolaevulinic acid (ALA) is a promising agent for photodynamic therapy (PDT) sensitization as it can be given orally and only causes skin photosensitivity for 1-2 days. In fluorescence and photodynamic studies 26 patients with benign and malignant gastrointestinal tumors were given 30-60 mg ALA orally (single or divided doses) and biopsies were taken of tumor and normal tissue at 1-24 hours for fluorescence microscopy. With 30 mg/kg, highest protoporphyrin IX (PPIX) levels were seen in esophagus, duodenum and less in colon, but without tumor selectivity. Better tumor selectivity was seen in colon after 60 mg/kg (5:1). Six patients had transient rises in transaminases and five mild nausea. Sixteen patients were later treated (after further ALA) with red light (628 nm, bare or diffuser fibre, 50-100 J at 50 mW at each site). All but two showed subsequent necrosis, but only 0.5-1.5 mm of depth. PDT with ALA is simple, safe and promising for tumors in the gastrointestinal tract. Modification of treatment parameters may make it suitable for larger lesions.
Mĺkvy
P
P
National Medical Laser Centre, University College London, Medical School, U.K.
Messmann
H
H
Regula
J
J
Conio
M
M
Pauer
M
M
Millson
C E
CE
MacRobert
A J
AJ
Bown
S G
SG
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D001711:Biotransformation; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D006801:Humans; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D010778:Photochemotherapy; D010865:Pilot Projects; D011524:Protoporphyrins / Q000378:metabolism / Q000493:pharmacokinetics*; D014018:Tissue Distribution
D011524:Protoporphyrins; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX