CLINICAL REPORT
689 ActaDV ActaDV Advances in dermatology and venereology Acta Dermato-Venereologica
Treatment of Actinic Keratosis with Photodynamic Therapy Using Red or Green Light: A Comparative Study
Beata J. OSIECKA 1, Piotr NOCKOWSKI 2 and Jacek C. SZEPIETOWSKI 2
1
Department of Pathology, and 2 Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Wroclaw, Poland
Actinic keratosis( AK) is the most common in situ cancerous skin lesion. Compared with other approved treat ment modalities photodynamic therapy is preferred by patients due to faster recovery and improved cosmetic outcome. However, pain during irradiation is an important drawback. The aim of this study was to compare the effectiveness and tolerability of topical aminolaevulinic acid-photodynamic therapy in the treat ment of AK on the head using red and green light. Complete remissions after 3 sessions of photodynamic therapy at 2-week intervals following 9 months of observation were 91.67 % for red light and 86.67 % for green light( difference not significant). The mean pain value was significantly greater in areas irradiated with red light compared with green light for all 3 sessions. This comparative study demonstrates that aminolaevulinic acid-photodynamic therapy with green light is of similar efficacy as that with red light in the treatment of middle / moderate AK, but causes less pain.
Key words: photodynamic therapy; red light; green light, 5-aminolevulinic acid; actinic keratosis; pain.
Accepted Mar 27, 2018; Epub ahead of print Mar 27, 2018 Acta Derm Venereol 2018; 98: 689 – 693.
Corr: Jacek C. Szepietowski, Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, ul. Chalubinskiego 1, PL-50- 368 Wroclaw, Poland. E-mail: jacek. szepietowski @ umed. wroc. pl
SIGNIFICANCE
Actinic keratosis is the most common early non-invasive stage of skin cancer. Compared with other approved treatment modalities photodynamic therapy is preferred by patients due to faster recovery and improved cosmetic outcome. However, pain during irradiation is an important drawback. This study shows that 3 sessions of topical aminolaevulinic acid-photodynamic therapy using green light is of similar efficacy as that with red light in the treatment of middle / moderate actinic keratosis, but irradiation with green light caused significantly less pain compared with red light.
Actinic keratosis( AK) is the most common in situ neoplasm of the skin in the white population, particularly in people with skin phototypes I – III. Epidemiological data show a rapid increase in AK morbidity in recent years. Lesions usually present as multiple erythematous or hyperkeratotic yellow, scaly plaques on skin areas damaged by ultraviolet( UV) light( photodamaged skin). Clinical research shows that 1 – 10 % of AKs progress to cutaneous squamous cell carcinoma( SCC).
Common treatments for AKs use various procedures, both ablative( cryosurgery, laser ablation, curettage, and surgery) and topical( 5-fluorouracil, diclofenac 3 % gel, and imiquimod). Some of these therapies may cause scarring or hyper- or hypo-pigmentation. Because most AKs are found in the sun-exposed skin( face skin, scalp, and hands), therapies offering the best cosmetic results are especially desirable.
Topical photodynamic therapy( PDT) with 5-aminolaevulinic acid( 5-ALA) has been approved as an alternative method of treating various precancerous( e. g. AK) and superficial tumours of the skin( 1 – 3). Safety, noninvasiveness, and excellent cosmetic results make PDT competitive with other conventional methods. Clinical studies have shown the effectiveness of ALA-PDT to be comparable to, or even exceed that of, cryotherapy, excisional surgery, or electrodesiccation in the treatment of AK( 4 – 7). Many patients who have previously undergone other FDA-approved treatment modalities for AK prefer PDT because of improved cosmetic outcome and faster recovery compared with cryotherapy and surgical excision. Moreover, PDT is better tolerated than 5-fluorouracil( 5-FU) and imiquimod( 8).
PDT is based on the interaction between 3 elements: a photosensitizer, an activating light source of the appropriate wavelength and oxygen. 5-ALA is selectively taken up by premalignant or malignant cells. In the target cells it is converted to protoporphyrin IX( PpIX), via the haem synthesis pathway. Exposure to light leads to activation of PpIX, formation of reactive oxygen species( ROS) and cytotoxicity of pathological cells( 9). PDT is typically induced by red light because of the optimal depth of light penetration into tissue. However, an important drawback of ALA-PDT is pain, often intense, experienced by patients during irradiation. Several studies have shown that, in the case of patients with AK on the forehead and scalp, PDT causes more pain than in cases of lesions in other areas( 10, 11). PDT offers clinical efficacy similar to standard treatments, but pain remains the most common adverse event reported. Therefore, new strategies are being sought in order to minimize discomfort during PDT.
The fact that a variety of wavelengths can initiate photodynamic reactions from ALA via PpIX in cells has led to interest in using green light( which is less penetrating) to treat superficial skin lesions. A number of clinical studies have reported that green light is effective in the
This is an open access article under the CC BY-NC license. www. medicaljournals. se / acta Journal Compilation © 2018 Acta Dermato-Venereologica. doi: 10.2340 / 00015555-2931 Acta Derm Venereol 2018; 98: 689 – 693