Methyl Aminolevulinate-PDT for Actinic Keratoses and Superficial Nonmelanoma Skin Cancers

B. Ortiz-Policarpio, MD; H. Lui, MD, FRCPC

Disclosures

Skin Therapy Letter. 2009;14(6) 

In This Article

AKs

A US randomized, multicenter, double-blind, placebo controlled study was performed in 80 patients with mild-to-moderate AKs on the face and scalp. Forty-two patients (260 lesions) were treated with MAL-PDT and 38 patients (242 lesions) received the placebo cream. MAL was applied for 3 hours followed by illumination with noncoherent red light (75J/cm2). Treatment was repeated after 1 week. A complete response rate of 89% with MAL-PDT and 38% with placebo was assessed after 3 months follow-up. An excellent or good cosmetic outcome was reported in more than 90% of patients treated with MAL.[10]

Tarstedt et al.[11] reported response rates in an open label, prospective study that compared 2 regimens:

  1. A single treatment session

  2. 2 MAL-PDT sessions 1 week apart.

One hundred six patients received the single treatment and 105 patients received the second regimen. For thin lesions, clearance rates showed no significant difference (93% with single session vs. 89% with double sessions) For thicker lesions, clearance rates were higher for double sessions (84%) when compared with single treatment (70%). The authors concluded that single treatment is effective for thin AKs. Repeated treatments were needed for thicker or resistant lesions.

In another randomized, multicenter study, MAL-PDT (n=360 lesions) was compared with a single-thaw cycle of cryotherapy (n=421 lesions) or placebo (n=74 lesions). The PDT treatment arm consisted of 2 treatment sessions 1 week apart using 75J/cm2 with a noncoherent red light (570-670nm). After 3 months, clearance rates for MAL-PDT were significantly higher (91%) compared with cryosurgery (68%) and placebo (30%). Of the MAL-PDT treated patients, 83% were rated as having an excellent cosmetic outcome by an investigator vs. 51% of those treated with cryotherapy; the corresponding patient assessments were 76% and 56% respectively.[12]

A large randomized, intraindividual, right-left comparative study of 119 patients with face/scalp AKs was performed.[14] The aim of the study was to compare 1 MAL PDT session to double freeze-thaw cryotherapy. After a 3-hour application of MAL using 37J/cm2 with double treatment 7 days apart, cure rates were seen when using MAL-PDT (87%) compared with cryotherapy (76%). Of patients treated with MAL-PDT, 10% required re-treatment after 3 months vs. 21% for cryotherapy. Cosmetic outcome significantly favored MAL-PDT (i.e., 77% vs. 50%).13 A recent study, however, showed lower efficacy with MAL-PDT (78% clearance) on the extremities compared with cryotherapy (88% clearance).[14]

In a recent multicenter, double-blind, randomized study by Pariser,15 the efficacy of MAL-PDT using a red light-emitting diode (n=363 lesions) was evaluated vs. placebo (n=360 lesions) for grade 1 (slightly palpable) and grade 2 (moderately thick) AKs on the face and scalp. Lesion complete response rates were significantly superior for MAL-PDT (86.2%) vs. placebo (52.5%). The patient complete response rate was 59.2% for MAL-PDT subjects, and lower for those who had vehicle PDT alone (14.9%). Scalp lesions responded better with MAL-PDT (93%) than did facial lesions (87%). Grade 1 lesions had slightly higher complete response rates than grade 2 lesions (89% vs. 80%). Furthermore, larger lesions with diameters of >20mm had poorer response rates compared with smaller lesions (74% vs. 86%).

When treating AKs, biopsies should be considered for thick, keratotic lesions to rule out squamous cell carcinoma. Calzavara-Pinton et al.[16] have shown that even if squamous cell carcinoma is limited to microinvasive involvement, the treatment outcome is poor.

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