Pulsed Dye Laser-mediated Photodynamic Therapy is Less Effective than Conventional Photodynamic Therapy for Actinic Field Cancerization: A Randomized Half-side Comparative Study

Field Cancerization Therapies for the Management of Actinic Keratosis: An Updated Review

Field cancerization theory highlights that the skin surrounding actinic keratoses (AK) is also at increased risk for possible malignant transformation; thus, field-directed treatments may both reduce the risk of AK recurrence and potentially reduce the risk of development of cutaneous squamous cell carcinoma (cSCC). Photodynamic therapy (PDT) with either aminolevulinic acid (ALA) or methylaminolevulinate (MAL), as well as topical treatments such as 5-fluorouracil (5-FU), diclofenac gel, piroxicam, imiquimod, and ingenol mebutate, have all shown higher efficacy than vehicle treatments. PDT is widely recognized for its high efficacy; however, concerns for associated pain have driven new studies to begin using alternative illumination and pretreatment techniques, including lasers. Among topical treatments, a combination of 5-FU and salicylic acid (5-FU-SA) has shown to be the most effective but also causes the most adverse reactions. Tirbanibulin, a new topical agent approved for use in 2020, boasts a favorable safety profile in comparison with imiquimod, 5-FU, and diclofenac. Meanwhile, ingenol mebutate is no longer recommended for the treatment of AKs due to concerns for increased risk of cSCC development. Moving forward, an increasing number of studies push for standardization of outcome measures to better predict risk of future cSCC and use of more effective measures of cost to better guide patients. Here, we present an updated and comprehensive narrative review both confirming the efficacy of previously mentioned therapies as well as highlighting new approaches to PDT and discussing the use of lasers and novel topical treatments for treatment of AK.

A Review of the Dermatologic Clinical Applications of Topical Photodynamic Therapy

Topical photodynamic therapy is a widely approved therapy for actinic keratoses and low-risk nonmelanoma skin cancers with a rapidly growing range of emerging indications for other cutaneous diseases. This review summarizes the best-available evidence to provide a clinical update for dermatologists on the approved and emerging indications of photodynamic therapy. The body of evidence suggests that photodynamic therapy is superior or noninferior to other available treatment modalities for actinic keratoses, low-risk basal cell carcinomas, Bowen's disease, skin field cancerization, chemoprevention of keratinocyte carcinomas in organ transplant recipients, photoaging, acne vulgaris, and cutaneous infections including verrucae, onychomycosis, and cutaneous leishmaniasis. There is emerging evidence that photodynamic therapy plays a role in the management of actinic cheilitis, early-stage mycosis fungoides, extramammary Paget disease, lichen sclerosis, and folliculitis decalvans but there are no comparative studies with other active treatment modalities. Common barriers to topical photodynamic therapy include procedural pain, costs, and the time required for treatment delivery. There is significant heterogeneity in the photodynamic therapy protocols reported in the literature, including different photosensitizers, light sources, number of treatments, time between treatments, and use of procedural analgesia. Topical photodynamic therapy should be considered in the management of a spectrum of inflammatory, neoplastic, and infectious dermatoses. However, more comparative research is required to determine its role in the treatment algorithm for these dermatologic conditions and more methodological research is required to optimize photodynamic therapy protocols to improve the tolerability of the procedure for patients.

Ablative Fractional Laser Enhances Artificial or Natural Daylight Photodynamic Therapy of Actinic Field Cancerization: A Randomized and Investigator-initiated Half-side Comparative Study

Artificial daylight photodynamic therapy is a near-painless treatment for actinic keratoses, which can be performed indoors using a controlled light dose. Daylight photodynamic therapy is approved only for treatment of grade I-II actinic keratoses. The aim of this study was to evaluate whether fractional laser pre-treatment improves the outcomes of daylight photodynamic therapy for actinic keratoses of all grades. In addition, the study compared the outcomes of artificial and natural daylight photodynamic therapy. This randomized single-blinded split-side comparative study included 60 patients with  ≥ 2 actinic keratoses of the head. Fractional laser pre-treatment was assigned randomly for actinic keratoses on 1 side of the head and, subsequently, the entire treatment area was treated with artificial or natural daylight photodynamic therapy. Fractional laser-mediated daylight photodynamic therapy achieved significantly higher complete clearance (50.0% vs 30.3%, p = 0.04), partial clearance (78.6% vs 50.0%, p < 0.01) and lesion-specific clearance (86.2% vs 70.2%, p < 0.01) than daylight photodynamic therapy alone at the 6-month follow-up. No significant differences were found in the outcomes of artificial vs natural daylight photodynamic therapy or grade I lesions vs grade II-III lesions. Thus, fractional laser pre-treatment appears to significantly increase the efficacy of artificial and natural daylight photodynamic therapy, and to be suitable for treatment of actinic keratoses of all grades.

Office-Based Photodynamic Therapy Using Locally Applied 5-aminolevulinic Acid and 635 nm Laser for Laryngeal Leukoplakia

OBJECTIVE

Photodynamic therapy (PDT) is a minimally invasive method with strong tissue selectivity and nonthermal effects. We aim to investigate the efficacy of an in-office method utilizing PDT with local application of 5-aminolevulinic acid (ALA) and 635 nm diode laser for treating laryngeal leukoplakia.

STUDY DESIGN

Retrospective cohort study.

SETTING

Outpatient clinic-tertiary medical center.

METHODS

This study reviewed 32 patients with laryngeal leukoplakia, including 11 recurrent cases after surgery. All the procedures were performed in an office setting under topical anesthesia. Fifteen percent ALA solution was locally applied to the lesion through a flexible laryngoscope. Light illumination was performed using a 635 nm diode laser through a 400 μm optic fiber. The power density was 165 mW/cm² to reach 100 J/cm² . Results of laryngostroboscopy and voice evaluation during follow-up were collected.

RESULTS

The mean follow-up was 7.91 ± 4.83 (3-18) months. Thirty-nine procedures were performed, including 1 session for 27 patients, 2 sessions for 3 patients, and 3 sessions for 2 patients. The total response rate was 96.875% (31/32), including complete responses in 26 (81.25%) patients, partial responses in 5 patients (15.625%), and no response in 1 patient (3.125%). It appeared that PDT selectively eliminated the leukoplakia without affecting lamina propria and the surrounding normal mucosa remained unharmed. Scores of Voice Handicap Index-10, jitter, shimmer, and harmonic-to-noise ratio were significantly improved after PDT.

CONCLUSION

Office-based PDT is an effective, repeatable, and practical method for treating laryngeal leukoplakia. Local application of ALA is sufficient to achieve photodynamic reactions. PDT could eliminate laryngeal leukoplakia selectively while protecting the normal laryngeal structure.