Effect of N-acetylcysteïne on Photofrin-induced skin photosensitivity in patients.
OBJECTIVE
One of the major side effects of photodynamic therapy (PDT) employing Photofrin as the sensitizer is enhanced photosensitivity of the skin. The basic mechanism in PDT damage is believed to be the formation of singlet oxygen and radical species. N-acetylcysteïne (NAC) increases glutathione levels and is known to prevent pathology elicited by radicals and reactive species.


METHODS
NAC was tested in a randomized, open label study for its protective effect on skin photosensitivity. Twenty-seven patients treated with PDT for central obstructive lung cancer or esophageal cancer received either "early" or "delayed" NAC, starting 5 or 10 days after Photofrin, in a dose of 3 x 600 mg per day for 5 days. Light, obtained from a halogen lamp (fluence rate 200 mW.cm-2) was used to illuminate skin patches of 2.5 cm2 on the back (10, 25, and 50 J.cm-2). Skin response was measured by using a visual scoring system and by measuring the redness using a reflectance meter.


RESULTS
Skin responses varied from no changes at 10 J.cm-2 to redness with edema at energies of 50 J.cm-2. In the absence of edema, measurements with the reflectance meter appeared to be more sensitive than visual scoring.


CONCLUSIONS
In a limited number of patients, there was a trend for decreased sensitivity after NAC, but statistical analysis failed to show any significant protective effect of this short course of NAC.
Baas
P
P
Division of Medical Oncology, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Huis, Amsterdam.
van Mansom
I
I
van Tinteren
H
H
Stewart
F A
FA
van Zandwijk
N
N
D000111:Acetylcysteine / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017323:Dihematoporphyrin Ether / Q000008:administration & dosage / Q000009:adverse effects*; D004487:Edema / Q000139:chemically induced / Q000517:prevention & control; D004890:Erythema / Q000139:chemically induced / Q000517:prevention & control; D004938:Esophageal Neoplasms / Q000532:radiotherapy; D005260:Female; D005500:Follow-Up Studies; D005609:Free Radicals / Q000009:adverse effects; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy / Q000009:adverse effects; D010787:Photosensitivity Disorders / Q000139:chemically induced / Q000517:prevention & control*; D017382:Reactive Oxygen Species / Q000009:adverse effects; D012867:Skin / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*
D005609:Free Radicals; D017382:Reactive Oxygen Species; D017323:Dihematoporphyrin Ether; D005978:Glutathione; D000111:Acetylcysteine