ABSTRACT
BACKGROUND: Reflectance confocal microscopy (RCM) is a noninvasive diagnostic technique with an acceptable sensitivity and specificity for actinic keratosis (AK). OBJECTIVES: We evaluated efficacy of daylight photodynamic therapy (DL-PDT) in patients with AK using a new RCM atypia scoring system. MATERIALS AND METHODS: All patients with AK lesions (Grade I-II) were included in our study (2012-15). Baseline clinical, dermoscopy and RCM evaluations were followed by DL-PDT. In the first follow-up, clinical examination, dermoscopy and RCM imaging of the treated area were carried out. Atypia scoring and cell size measurements were used to compare before and after RCM images. RESULTS: From 40 lesions (20 patients with mean age of 75·5 years), complete resolution and partial response of the actinic damage was detected in 80% and 17·5% of lesions, respectively. No cellular atypia was seen in the follow-up RCM images of 57·5% of lesions (n = 23), while in 40% of lesions (n = 16) minimal changes to the honeycomb pattern of the epidermis were seen in the follow-up RCM images (atypia score 1). Only one lesion showed minimal or no clinical response, and a persistent moderate amount of atypia in RCM. Furthermore, atypia score and mean cell size decreased significantly in the follow-up DL-PDT RCM images (P < 0·001, P = 0·001, respectively). CONCLUSIONS: RCM features of actinic damage at cellular level have been shown to correlate well with the results of a clinical assessment of AK lesions. This study confirms that in vivo RCM technology might be an additional technique to monitor the efficacy of DL-PDT for AK.
