Actinic Keratosis (AK) is a chronic disease that can manifest in single or multiple lesions, including subclinical lesions that are invisible to the naked eye. In Hawaii, where the sun shines all year long, dermatologists are no strangers to patients with AK. Speaking at Maui Derm 2016, George Martin, M.D. shared some innovative refinements of conventional AK treatments.
The tip of the iceberg
Dr. Martin, who is a solo practitioner at Dr. George Martin Dermatology Associates of Maui, Kihei, Hawaii, says that âClearly, singular lesions are best and most conveniently treated with liquid nitrogen. However, the presence of a single AK can be deceiving in terms of the true scope of disease because we dermatologists feel that one AK is usually just the tip of the iceberg. There are likely many subclinical AKs [i.e., field cancerization] present in normal appearing skin.â
Field cancerization requires field therapy. Although there are many different modalities available for the treatment of AKs, Dr. Martin says that less than 10% of dermatologists use field therapy on their patients. Some of the reasons include the tremendous downtime associated with therapy (weeks to months) and pushback from patients because of the cosmetic side effects. The pain associated with treatment often directly impacting patient compliance.
âUnfortunately, conventional PDT can be very painful. While off-label daylight-mediated PDT can achieve upwards of 75% clearance rates and can shift the pain paradigm significantly, this approach is not feasible in the US for many reasons, including weather issues and legal issues, as well as insurance reimbursement,â Dr. Martin says. The off-label, daylight-mediated approach is 30 minutes of MAL PDT followed by 1Â½-2Â½ hours of natural sunlight exposure with sunscreen.
Any one of the field therapies will result in varying degrees of oozing, crusting, and pain, which at times can be significant for some patients. Recognizing the therapeutic power, and the drawbacks, of standing agents and modalities such as PDT, Dr. Martin set out to optimize the treatment regimen by adjusting the parameters of in-office PDT therapy. Dr. Martin recently conducted a prospective split-face study1 in 3 patients, including treatment associated pain measurements in over 100 patients with AKs, comparing short ALA incubation times of 15 minutes followed by 60 minutes of continuous blue light exposure versus traditional ALA PDT.