Laser-assisted photodynamic therapy for superficial basal cell carcinoma and Bowen's disease: a randomized intrapatient comparison between a continuous and a fractional ablative CO2 laser mode

Abstract

Background: Laser-assisted photodynamic therapy is being explored as a method to enhance efficacy of photodynamic therapy (PDT).

Objective: To compare a continuous (CL) and a fractional (FL) ablative CO₂ laser-assisted methyl aminolevulinate (MAL) PDT in the management of superficial basal cell carcinoma (sBCC) and Bowen's disease (BD).

Methods: Thirty treatment areas in fifteen patients with inoperable, histologically verified sBCC or BD received CL or FL after intrapatient randomization. Laser treatment was followed by MAL application and illumination occurred 3 h later. This treatment was repeated after 2 weeks. An equivalence analysis was performed on the primary endpoint efficacy, while secondary endpoints pain, side-effects and aesthetics were evaluated using paired samples tests. Patients were also asked for their preferred treatment.

Results: An excellent efficacy of 92.9% (sBCC, 100%; BD, 80%) was found in both CL + PDT and FL + PDT after 12 months. Equivalence could not be established. Little pain was perceived in most patients during PDT illumination. PDT treatment in FL + PDT was less painful, significantly during the second treatment (P = 0.026). Side-effects were mild to moderate with erythema being the most frequent immediate side-effect, followed by oedema, crusting and burning sensation. Pigmentary changes occurred in 21% (CL + PDT) to 29% (FL + PDT), and aesthetics were good to excellent in all patients. CL + PDT and FL + PDT did not significantly differ in side-effects (P = 0.219-1.000) or aesthetics (P = 0.157-1.000).

Conclusions: Results in this pilot study support the promising role of laser-assisted PDT. Both treatment arms demonstrated the same efficacy as well as comparable side-effects and aesthetics. PDT illumination was significantly less painful in the FL + PDT group, suggesting a preference for FL + PDT. The authors recommend further investigation with a larger sample size, a subgroup analysis between sBCC and BD and comparison of different treatment protocols before one technique could be preferred to another.