A prospective study of pain control by a 2-step irradiance schedule during topical photodynamic therapy of nonmelanoma skin cancer.
BACKGROUND
Topical photodynamic therapy (PDT) for selected nonmelanoma skin cancer using 5-aminolevulinic acid (ALA) or methyl aminolevulinate (MAL) has yielded high long-term complete response rates with very good cosmesis. Pain during light activation of the photosensitizer can be a serious adverse event. A 2-step irradiance protocol has previously been shown to minimize ALA-PDT pain.


OBJECTIVE
To determine the irradiance-dependent pain threshold for MAL-PDT, to adapt the 2-step protocol to a light-emitting diode (LED) light source, and assess clinical response.


METHODS
In this prospective study, 25 superficial basal cell carcinoma (sBCC) received an initial irradiance by laser at 40 or 50 mW/cm², or LED at 35 mW/cm² followed by an irradiance at 70 mW/cm² for a total of 75 J/cm². Pain levels were recorded for both irradiance steps. Efficacy was assessed at 6, 12, or 24 months.


RESULTS
Pain was mild in the 40/70 mW/cm² laser cohort. Three instances of irradiance-limiting pain occurred at 50/70 mW/cm². Pain was minimal in the 35/70 mW/cm² LED cohort. Clinical response rates were 80% in the 50/70 mW/cm² laser cohort and 90% in the 35/70 mW/cm² LED cohort.


CONCLUSIONS
Topical PDT can be effectively delivered to sBCC with minimal treatment-related pain by a 2-step irradiance protocol.
*Department of Dermatology, University of Arizona Cancer Center, Tucson, Arizona; Departments of †Cell Stress Biology/PDT Center, ‡Dermatology, and §Biostatistics and Bioinformatics, Roswell Park Cancer Institute, Buffalo, New York; ‖Department of Imaging Sciences, University of Rochester, Rochester, New York.
Nathalie C
NC
Zeitouni
Ulas
U
Sunar
Daniel J
DJ
Rohrbach
Anne D
AD
Paquette
David A
DA
Bellnier
Yi
Y
Shi
Gregory
G
Wilding
Thomas H
TH
Foster
Barbara W
BW
Henderson
D000328:Adult; D000368:Aged; D000622:Aminolevulinic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D002280:Basal Cell Carcinoma / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D059408:Pain Management; D010147:Pain Measurement; D017288:Pain Threshold; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011446:Prospective Studies; D012878:Skin Neoplasms / Q000188:drug therapy*; D016896:Treatment Outcome
D017319:Photosensitizing Agents; C475457:methyl 5-aminolevulinate; D000622:Aminolevulinic Acid