Imiquimod Treatment for Actinic Keratosis

By Mark Lebwohl, MD

New York, New York 10029

Physician (MD, DO), Dermatology

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An Actinic keratosis (AK) is a common precancerous skin lesion that is normally treated by dermatologists using cryotherapy, (freezing). Now, a new study published in the September issue of the Journal of Drugs in Dermatology (JDD) shows that treatment outcomes may be improved by combining cryotherapy with Zyclara® (imiquimod), 3.75%.

Imiquimod is a medication that is used for the treatment of a variety of skin conditions, including actinic keratoses, basal cell carcinoma and external genital warts. Imiquimod appears to activate the immune system to help rid the body of abnormal cells.

According to this study, “A Randomized, Double-blinded, Placebo-controlled, Multicenter, Efficacy and Safety Study of 3.75% Imiquimod Cream Following Cryosurgery for the Treatment of Actinic Keratoses”, the use of imiquimod (Zyclara® cream) following cryotherapy yielded better results when treating actinic keratoses over the use of cryotherapy alone.

There a several options available for removing an individual actinic keratosis (AK). However, the region around an AK lesion is also sun-damaged and at risk of developing new actinic keratoses over time, requiring additional treatments. In one previous study, only 4% of patients who received only cryotherapy as an actinic keratoses treatment had sustained clearance one year later in the area around the original AK lesion.

There has been growing in interest in combining a procedure that removes an actinic keratosis with a medication, such as 5-FU or imiquimod, that treats the surrounding region.

In this study, adults with at least 10 actinic keratoses on the face underwent cryotherapy of 5 to 14 lesions. Those with at least 5 actinic keratoses remaining were randomized to receive 3.75% imiquimod (Zyclara®) or a placebo cream applied to the entire face daily for two two-week cycles. Efficacy of these two treatment options was assessed 26 weeks later.

Dermatologist Mark Lebwohl, M.D. and the other study authors concluded that “while cryosurgery is an effective treatment for actinic keratoses, the subsequent use of 3.75% imiquimod cream (Zyclara®) is safe and well tolerated and provides additional therapeutic benefits to cryosurgery alone. These results suggest that dual-mode therapy with lesion-directed cryosurgery followed by field-directed 3.75% imiquimod cream may be an appropriate option for patients with multiple actinic keratoses on the face.

The study also “confirmed the findings of previous investigators regarding the efficacy of two two-week treatment cycles of daily 3.75% imiquimod cream (Zyclara®) to treat all actinic keratoses in a large field of application.

It has been previously reported that imiquimod, the active ingredient of branded medications Aldara® and Zyclara®, can cause subclinical lesions to become visible. This “unmasking” effect is felt to be of clinical benefit as lesions that may have otherwise have been missed are being treated. Photographs of actinic keratosis and basal cell carcinomas before, during and after treatment show the unmasking of subclinical disease.

An actinic keratosis is a skin lesion that tends to appear on sun-exposed parts of the body, including the scalp, top of the ears, face and backs of the hand. AKs may be scaly or crusty, and may be red, pink, tan, or brown-colored. Actinic keratoses are routinely treated by dermatologists because they are at risk of developing into a type of skin cancer called “squamous cell carcinoma.”