An open pilot study of ambulatory photodynamic therapy using a wearable low-irradiance organic light-emitting diode light source in the treatment of nonmelanoma skin cancer

Abstract

Photodynamic therapy (PDT) is a popular treatment for nonmelanoma skin cancer with clearance rates of between 70% and 100%. Although reported to have a superior cosmetic outcome, the inconvenience of hospital visits and discomfort during therapy are considered drawbacks. To present an open pilot study of a low-irradiance, potentially disposable, lightweight, organic light-emitting diode (OLED), which is an area-emitting light source (2 cm diameter), suitable for ambulatory PDT. Twelve patients with Bowen's disease (eight) and superficial basal cell carcinoma (four) < 2 cm in diameter were recruited into the study following histological confirmation of the diagnosis. Two treatments (45-60 J cm(-2) red light, 550-750 nm, peak 620 nm, irradiance 5 mW cm(-2)) were administered 1 month apart following application of aminolaevulinic acid for 4 h. At the 12-month follow-up, seven of the 12 patients remained clear, with four of the nonresponders demonstrating peripheral margin failure. Patients were scored for pain during and immediately after treatment using the numerical rating scale (NRS; 1-10). All 12 subjects scored pain as < 2 using the NRS (median score 1). In contrast, a similar cohort of 50 consecutive patients from our routine PDT clinic (Aktilite inorganic LED source; 75 J cm(-2), irradiance 80 mW cm(-2)) scored a median of 6 on the NRS. Pain and inconvenience are practical barriers to the use of conventional PDT. This pilot study suggests that OLED-PDT is less painful than conventional PDT with the added advantage of being lightweight, and therefore has the potential for more convenient 'home PDT'. These results need to be validated in larger studies.