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New once-daily cream allows individualized treatment of actinic keratosis

True or false? Skin cancer is the most common form of cancer in the United States. Though it may come as a surprise to some, the answer is true. The American Cancer Society estimates that more than one million new cases of skin cancer will be diagnosed, and the disease will claim the lives of almost 10,000 people this year.

One of the warning signals for this largely preventable cancer is actinic keratosis (AK). According to the Skin Cancer Foundation, one out of every six Americans will develop an AK in his or her lifetime. Even if you are unfamiliar with the term AK, its appearance is commonplace. Anyone who spends time in the sun runs a high risk of developing one or more AKs. National awareness has been increased as more celebrities are diagnosed with AK, including Clint Eastwood, Robert Redford, Regis Philbin, and professional golfer Andy North.

Actinic keratoses, also known as solar keratoses, are small scaly lesions commonly found on the areas of the body that are exposed to the sun, such as the face, ears, lips, scalp, neck, back of hands, and forearms. If detected and treated in the early stages, AKs are not life-threatening, but up to 10% can develop into squamous cell carcinoma, which can be fatal if allowed to metastasize.

"This is not a problem only for your grandparents," commented Joseph Jorizzo, M.D., at a recent press briefing in New York. He is professor and chair of the Department of Dermatology at Wake Forest University School of Medicine in Winston-Salem, N.C. Many of his patients who are in their twenties and thirties are already showing signs of sun-damaged skin.

So what options are available for treating AK? Dermatologists generally perform cryosurgery for an individual AK, which involves freezing the lesion with liquid nitrogen. But, as Jorizzo pointed out, AKs occur in clusters. "There is more under the surface than can be seen with the eye," he said. "And where there is one, there are usually more lurking underneath the surface." For patients who have multiple AKs, physicians often prescribe a topical chemotherapy cream.

It was quite by accident, as is often the case, that it was discovered that fluorouracil given systemically to treat invasive cancers also improved the look and feel of sun-damaged skin. One of the limitations with the earlier cream formulations of fluorouracil was the high incidence of skin irritation that ensued following therapy. Jorizzo explained that the older fluorouracil versions were high in concentration (5%) and required twice-daily dosing for two to four weeks, with a healing time that could last two months, drastically reducing patient compliance.

Dermik Laboratories has developed a new topical treatment for multiple actinic or solar keratoses of the face and anterior scalp. Carac (fluorouracil cream), 0.5%, has been approved by the Food & Drug Administration. The convenient once-daily formulation is one-tenth of the dose of previous agents. Carac will offer "another approach to treating AKs that will allow the physician and the patient to individualize therapy to that particular patient," noted Sharon Levy, M.D., Dermik's director of clinical research and medical affairs.

Results from two phase III double-blind studies indicated that Carac effectively treats AKs of the face and anterior scalp with one, two, or four weeks of treatment when used once daily. The most common adverse effects seen were application-site reactions, such as redness, dryness, burning, erosion, and swelling. Some patients also experienced eye irritation, including stinging and burning.

"It presents a different profile in terms of irritation," said Levy. While irritation is an expected response, typically beginning on the fourth day of treatment, it was generally resolved within two weeks after therapy was discontinued. She expects this will aid in improving patient compliance.

Levy explained that while their study did not include cryotherapy, "you can see the kind of 'marriage,' therapeutically, the physician is going to gravitate to," using cryotherapy for the visible, thick lesions followed by Carac for those underlying lesions.

Tammy Chernin, R.Ph.

TIPS TO REMEMBER: Carac

• Carac's safety has not been established in patients less than 18 years of age. It is contraindicated in women who are or may become pregnant.

• The affected area should be cleansed 10 minutes prior to applying Carac, and hands should be thoroughly washed immediately after application.

• Avoid prolonged exposure to sunlight or other forms of UV irradiation during treatment.

• Carac cream should not be applied near the eyes, nostrils, or mouth.

 

Tammy Chernin. New once-daily cream allows individualized treatment of actinic keratosis. Drug Topics 2001;9:24.