Daylight photodynamic therapy: What is known and what is yet to be determined

BACKGROUND Photodynamic therapy (PDT) has been used extensively to treat actinic keratoses (AKs) and less so nonmelanoma skin cancers (NMSC). Conventional in-office treatment is limited by intensive time requirements and patient discomfort. A new trend toward the use of daylight as a light source either clinically monitored or self-supervised is gaining acceptance. OBJECTIVE To assess the current published data on daylight photodynamic therapy (dPDT) and identify knowledge gaps. METHODS AND MATERIALS A systematic search of the PubMed archives using the terms daylight PDT, daylight-PDT, daylight photodynamic therapy, and ambient light and photodynamic therapy was conducted on May 18, 2015. No restrictions were used for the search string. RESULTS Seventeen published works were identified on the use of dPDT; 8 randomized studies, 4 prospective cohort studies, 1 case series, 1 case report, and 3 retrospective studies. Complete response rates for treatment of AKs from randomized trials range from 46% to 89.2%. CONCLUSION Daylight PDT has been demonstrated to have high efficacy with results similar to conventional PDT for the treatment of AKs. Initial reports regarding treatment of NMSC indicate recurrence rates much higher than other accepted therapies. Pain associated with treatment seems to be significantly less than for conventional PDT.