Comparison of aminolevulinic acid (ALA)-thermogel-PDT with methyl-ALA-thermogel-PDT in basal cell carcinoma

Summary 

Background

Aminolevulinic acid (ALA) and light irradiation is a treatment option in basal cell carcinomas (BCC). The development of ALA-esters with potential for greater penetration depth promises higher therapeutic success. In a pilot study, we hypothesized that the cytotoxic effect of methyl-ALA (mALA) photodynamic therapy (PDT) leads to a higher success rate compared with ALA-PDT when both are topically applied in a thermogel.

Methods

Twenty-four patients with 112 superficial BCC were treated with either 10% ALA- or mALA-thermogel. After an accumulation time of at least 3h, the lesions were illuminated with a diode laser. The power density was 0.1W/cm² and the energy density was 120J/cm². After intervals of 12 weeks and 6 months, the therapeutic efficacy was assessed by clinical examination.

Results

Sixty percent of the tumors were treated successfully in the first session. All but 3% of the remaining tumors could be treated with a second or third course of therapy.

Conclusion

Although mALA should have a greater penetration depth, the therapeutic outcome of this preliminary study showed no difference between treatments. The final proof of this preliminary result will require further study.

Keywords: Photodynamic therapy, Basal cell carcinomas, Therapeutic success, Aminolevulinic acid, Methylated aminolevulinic acid, Topical thermogel application