Oscillating abrasive device matches curettage and sandpaper for AK skin prep before ADL-PDT

BACKGROUND: Photodynamic therapy (PDT) is recommended as a first-line treatment for multiple actinic keratoses (AK) and field cancerized skin. When using PDT, skin preparation is recommended before application of photosensitizer cream to enhance absorption. Different physical methods exist to remove crusts and scales from the AK lesions. However, currently widely used methods can be time-consuming, unpleasant to the patient, or require expensive equipment. OBJECTIVES: To investigate the performance, safety, and comfort of a novel skin preparation device consisting of a soft biocompatible abrasive pad attached to an oscillating device, compared to widely used methods such as curettage and manual microdermabrasion. METHODS: Before artificial daylight PDT (ADL-PDT) all patients (n = 22) underwent skin preparation with the oscillating abrasive device and either curettage (n = 11) or manual microdermabrasion with sandpaper (n = 11). Removal of hyperkeratotic skin and operation times were evaluated. Safety was defined through skin warming (SW), skin irritation (SI), and skin damage (SD). Device comfort was monitored by user and patient questionnaires. Skin preparation was repeated if needed on Day 14 before second ADL-PDT session. Patients determined pain using numerical rate scale (NRS) during skin preparation and ADL-PDT. AK clearance was measured with number and Olsen grade of AKs assessed on Day 0, Day 14, and at 4 months. RESULTS: Primary outcomes: Skin preparation times of AK lesions using the oscillating abrasive device was 15.2 s/10 cm compared to manual sandpaper 26.6 s/10 cm (P = 0.0136) and curettage 22.3 s/10 cm (P = 0.1573). Hyperkeratotic lesions were easily removed with oscillating device for 95.5% (n = 21/22) of the patients. Corresponding values for curettage were 81.8% (n = 9/11, P = 0.10) and for sandpaper 54.5% (n = 6/11, P = 0.0096). More thorough work was required to remove hyperkeratotic lesions for 18.2% of patients (n = 2/11) in the curettage group and for 27.3% of patients (n = 3/11) in the sandpaper group. Some lesions remained on the skin area prepared with the oscillating device in one patient (4.5%, n = 1/22) and in two patients with sandpaper (18.2% n = 2/11). SECONDARY OUTCOMES: Skin warming was reported more often with oscillating device (SW: n = 10/22), but caused less irritation (SI: n = 2/22) and skin damage (SD: n = 1/22), compared to curettage (SW: n = 1/11, SI: n = 5/11, SD: n = 8/11) and manual sandpaper (SW: n = 4/11, SI: n = 2/11, SD: n = 2/11). All reported cases of SW, SI and SD were mild. Device comfort was in general assessed by patients as neutral: oscillating device (n = 17/22), curettage (n = 8/11) and sandpaper (n = 9/11). Vibration of the oscillating device was assessed as neutral by many patients (n = 16), pleasant by four patients (n = 4) and unpleasant by two patients (n = 2). None of the patients found the vibration very unpleasant. The mean pain scores (NRS) were low during skin preparation (oscillating device 1.1, curettage 1.8, sandpaper 1.7) and even lower during ADL-PDT (oscillating device 0.6, curettage 0.4, sandpaper 1.0). Total number of AK lesions were 260 on Day 0, with a reduction to 56 AK lesions on Day 14 (Olsen grade 1: n = 46/108, Olsen grade 2: n = 10/116, Olsen grade 3: n = 0/35). All lesions were cleared at 4-month follow-up. CONCLUSIONS: The novel oscillating abrasive skin preparation device was as safe and as effective as curettage and manual microdermabrasion in preparation of AKs before ADL-PDT.