Daylight-Mediated Photodynamic Therapy With Methyl Aminolevulinate in Actinic Keratosis Treatment

Updates on Treatment Approaches for Cutaneous Field Cancerization

Purpose of Review

Field cancerization describes the phenomenon that multiple heterogenous mutations may arise in an area exposed to chronic carcinogenic stimuli. Advances in the understanding of cutaneous field cancerization have led to novel therapeutic approaches to the management of actinic keratoses (AKs). Herein, we review the literature on the pathophysiology and emerging research of field cancerization in dermatology.

Recent Findings

The classification systems for grading AK lesions are being refined with investigations focusing on their clinical utility. There is a growing shift towards field-directed treatment for AKs as the importance of field cancerization becomes clearer. Current field-directed therapies are being optimized and novel therapeutic modalities are being studied.

Summary

Field cancerization underlies the transformation of photodamaged skin into AKs and potentially cutaneous SCC (cSCC). Clinically meaningful classification systems for AKs are needed to better inform decisions regarding treatment. As we learn more about the role of field characterization in photodamage, AKs and cSCCs, therapeutic strategies are becoming more field-directed rather than lesion-directed.

Photodynamic therapy activated by intense pulsed light in the treatment of actinic keratosis

BACKGROUND

Actinic keratosis (AK), a hyperkeratotic lesion induced by solar exposure, is the precancerous lesion that most frequently develops into squamous cell carcinoma. Cryotherapy, topical fluorouracil 5, topical diclofenac 3% gel and, more recently, ingenol mebutate are used in addition to surgery. However, these treatments have varying degrees of effectiveness and are not always tolerated due to side effects. In recent years, photodynamic therapy (PDT), has asserted itself as a new effective and safe method for the treatment of actinic keratoses with almost no side effects. The aim of this study is to verify whether a third treatment may now be added to the "Conventional -PDT" and "Daylight-PDT": PhotoDynamic Therapy activated by Intense Pulsed Light (IPL-PDT).

METHODS

Thirty-one patients, 24 males and 7 females, in most cases elderly, were included in the trial. As in the previous methods, also in IPL-PDT, 5-methylaminolevulinic acid (MAL) was applied topically for a period of 3 hours. Thereafter, the occlusive dressing and the topical cream, were removed and the neoformation was irradiated with IPL, with a 640 nm filter with variable power. Irradiation was performed in single or multiple sessions, depending on the type of keratosis, to completely cover the lesion and the apparently healthy surrounding areas, i.e. the cancerization field.

RESULTS

Results were evaluated 3, 6 and 9 months after treatment. Treatment achieved a 95% complete clearance rate, with a 5% partial relapse, 9 months after the last treatment.

CONCLUSIONS

The above method is a valid alternative to methods already in use. The results obtained demonstrate the efficacy and tolerability of the treatment described which, due to its versatility and speed of use, is preferable to the methods used so far.