Liquid nitrogen: Temperature control in the treatment of actinic keratosis

Background Actinic keratoses (AKs) are in situ epidermal tumors that may progress to invasive squamous cell carcinomas. Liquid nitrogen is used during cryotherapy to freeze the epidermis and upper dermis and is the standard treatment for individual AKs. Objective To evaluate the efficacy of a cryosurgery device incorporating an infrared sensor to measure the temperature at the skin surface while spraying liquid nitrogen on the surface of the skin during the treatment of AKs. Methods & MATERIALS Thirty-six patients with 180 thin AKs were treated with liquid nitrogen spray to a temperature of -5°C using the sensor to control the temperature at the skin surface. Patients were evaluated for cure rate, side effects, and healing time. Results At the 1-week follow-up, 66.7% of the lesions were cleared. By the 6-week follow-up, there was a 100% cure rate. Side effects were limited to redness, blistering, crusting, oozing, and ulceration at the 1-week follow-up and were resolved by the 6-week follow-up. No recurrence of AK, scarring, or hypopigmentation was noted. Conclusion Cryotherapy with an integrated sensor for temperature control is an effective, safe, and precise treatment, allowing for a 100% short-term cure rate of AKs. The Cryotracker used in this study was given to the authors by the Brymill Company.