A review of laser and photodynamic therapy for the treatment of nonmelanoma skin cancer.

Abstract

The role of laser and light sources used alone and in conjunction with photodynamic therapy (PDT) for the treatment of nonmelanoma skin cancers (NMSCs) remains unclear. PDT is a newly accepted treatment option for actinic keratoses (AKs) with clearance rates comparable to 5-flourouracil. The purpose of this study was to review literature pertaining to the use of light-emitting technologies and PDT for the treatment of basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and AKs. A National Library of Medicine PubMed Internet search of English-language journals was performed using the terms laser, PDT, BCC, SCC, and AK. The search encompassed all English-language clinical trials on human subjects from the mid-1960s to the present using laser and light source therapy and/or topical aminolevulinic acid. Articles were excluded if they contained fewer than 10 patients, had a follow-up time of less than 1 month, used intravenous photosensitizers, or were review articles. A total of 20 papers were included for review (10 for BCC, 4 for AK, and 6 for SCC). Follow-up for these patients ranged from 1 to 36 months. Clearance rates were reported up to 100% for superficial BCCs, AKs, and SCC in situ, and lower (8%) for more invasive SCC. Recurrence rates ranged from to 0% to 31% for superficial BCCs, 16% to 31% for AKs, 0% to 52% for SCC in situ, and 82% for invasive SCC. Precise PDT and laser clearance and recurrence rates for superficial and nodular BCC and SCC treated with laser and PDT are not yet known. From the available data, it appears that PDT may be capable of achieving clearance rates comparable to radiation therapy for BCC. However, with current technology, PDT treatment of BCC remains inferior to surgical excision and Mohs surgery, for which recurrence rates have been reported to be less than 10%. The reported clearance rates currently limit the usefulness of PDT and laser therapy. However, multiple treatments and the use of penetration enhancers may significantly increase the efficacy of 5-aminolevulinic acid-PDT. With regard to SCCs, the risk of metastatic disease restricts the use of laser and PDT. Studies are currently underway with new light sources, photosensitizers, and various therapeutic regimens. At this time, because the reported recurrence rates are significantly higher than those achieved with standard therapies, laser and PDT should be reserved for only those patients who cannot undergo surgical therapy for BCC and SCC.