What is actinic keratosis and its management?

From the Guidelines

Actinic keratosis is a precancerous skin lesion that should be managed with field treatment using 5-fluorouracil or imiquimod, as well as preventive measures such as UV protection, as recommended by the guidelines of care for the management of actinic keratosis 1. Actinic keratosis is a precancerous skin lesion caused by chronic sun exposure, appearing as rough, scaly patches typically on sun-exposed areas like the face, scalp, ears, and hands. Management includes both preventive measures and treatment options.

Prevention and Treatment Options

Prevention focuses on sun protection with broad-spectrum sunscreen (SPF 30+), protective clothing, and avoiding peak sun hours.

• The use of UV protection is strongly recommended for patients with actinic keratosis, as stated in the guidelines of care for the management of actinic keratosis 1.
• Field treatment with 5-fluorouracil or imiquimod is also strongly recommended for patients with actinic keratosis, based on moderate evidence 1. Treatment options vary based on the number and location of lesions.
• For isolated lesions, cryotherapy with liquid nitrogen is commonly used, freezing the affected tissue, and is strongly recommended by the guidelines of care for the management of actinic keratosis 1.
• Topical medications include 5-fluorouracil (Efudex, applied twice daily for 2-4 weeks), imiquimod (Aldara, applied 2-3 times weekly for 4-16 weeks), and diclofenac gel (Solaraze, applied twice daily for 60-90 days), with diclofenac being conditionally recommended due to lower quality of evidence and potential cardiovascular and gastrointestinal side effects 1.
• For multiple lesions, field therapy with photodynamic therapy may be used, involving application of aminolevulinic acid followed by light exposure, and is conditionally recommended by the guidelines of care for the management of actinic keratosis 1.

Importance of Treatment

Treatment is important because approximately 5-10% of actinic keratoses can progress to squamous cell carcinoma if left untreated.

• Regular skin examinations are recommended for early detection of new lesions or changes in existing ones, allowing for timely treatment and prevention of progression to squamous cell carcinoma. The guidelines of care for the management of actinic keratosis provide a comprehensive approach to the management of actinic keratosis, emphasizing the importance of preventive measures, field treatment, and regular skin examinations 1.

From the FDA Drug Label

1.1 Actinic Keratosis Imiquimod Cream is indicated for the topical treatment of clinically typical, nonhyperkeratotic, nonhypertrophic actinic keratoses on the face or scalp in immunocompetent adults. Actinic keratoses are pre-cancerous lesions that can progress to squamous cell carcinoma if left untreated. There is no direct information in the provided drug labels about the definition and management of actinic keratosis. Actinic keratosis is not explicitly defined in the provided text, but it is described as a condition for which imiquimod cream is indicated for treatment. The management of actinic keratosis using imiquimod cream involves applying the cream to the affected area 2 times per week for 16 weeks 2.

• The treatment area can be on the face or scalp.
• The cream should be applied prior to normal sleeping hours and left on for approximately 8 hours.
• Efficacy is assessed by the complete clearance rate, defined as the proportion of subjects with no clinically visible AK lesions in the treatment area 8 weeks after the last scheduled application of study cream 2.

From the Research

Definition and Characteristics of Actinic Keratosis

• Actinic keratosis (AK) is a skin lesion characterized by intraepithelial keratinocyte dysplasia and molecular alterations shared with normal chronically sun-damaged skin and squamous cell carcinoma (SCC) 3, 4.
• AK can undergo spontaneous regression, stable existence, or malignant transformation to cutaneous SCC with progression rates to SCC ranging from 0% to 0.5% per lesion-year and AK spontaneous regression of 15-63% 4.
• AK is a potential precursor of invasive SCC, and it is commonly treated to mitigate the risk of malignant progression, including metastasis and death 4, 5.

Management and Treatment of Actinic Keratosis

• Treatment options for AK include topical medications, photodynamic therapy, cryosurgery, and laser ablation 5.
• Lesion-directed treatments, such as cryotherapy, electrodessication and curettage, and surgery, are used for few visible AKs 3.
• Field-directed therapies, including topical and ablative treatments, are used for multiple and/or subclinical (non-visible) AKs 3.
• Strong recommendations are presented for using ultraviolet protection, topical imiquimod, topical 5-fluorouracil, and cryosurgery 5.
• Conditional recommendations are presented for the use of photodynamic therapy and diclofenac for the treatment of AK, both individually and as part of combination therapy regimens 5.
• A treatment algorithm that differentiates patients according to whether they have isolated scattered lesions, lesions clustered in small areas or large affected fields can be used to guide treatment decisions 6.
• Orally administered nicotinamide has shown to significantly reduce rates of new non-melanoma skin cancer and AK in high-risk patients 7.

Goals and Considerations of Actinic Keratosis Treatment

• The goals of treatment are to eliminate visible AKs and to treat subclinical (non-visible) AKs, minimizing their risk of progression to invasive SCC, while pursuing good cosmesis 3.
• Predicting which AK will progress to SCC is difficult, and so all are treated 3.
• The current best approach is the sequential treatment with a lesion-directed and a field-directed therapy, and several combinations seem to work well 3.
• Treatment selection should be based on local availability, and the presentation and needs of the patients 6.