Background and design: A variety of therapeutic regimens has been used in keloids and hypertrophic scars with unsatisfactory final results. Application of cryosurgery could be beneficial since it was reported to produce less scarring after treatment of skin tumors compared with other surgical procedures. We performed a prospective consecutive trial of randomly enrolled case series including 32 months of average follow-up to assess the outcomes of cryosurgical treatment in keloids and hypertrophic scars and to determine factors influencing the therapeutic result. Ninety-three white patients, aged 10 to 79 years (median age, 26 years) with keloids (n = 55; median duration, 36 months; median size, 4 cm2) and with hypertrophic scars (n = 38; median duration, 12 months; median size, 2 cm2) were treated using the contact method. One freeze-thaw cycle of 30 seconds per lesion and session was employed, and, if needed, treatment was repeated every 20 to 30 days.
Results: Excellent responses (ER) were recorded in 30 subjects (32.3%), good responses (GR) in 27 (29.0%), poor responses (PR) in 27 (29.0%), while nine subjects (9.7%) did not respond at all. Hypertrophic scars responded better (n = 38; GR to ER, 76.3%) than keloids (n = 55; GR to ER, 50.9%; P < .005; odds ratio, 6.92). No progressions or recurrences occurred. Histologically, neovascularization, loss of the anarchic arrangement of collagen bundles, increased fibroblasts in a stroma running parallel to the skin surface, and mononuclear cells mostly arranged at the perivascular area were found in clinically responding lesions. Improved responses were detected in subjects treated with three or more sessions (n = 57; GR to ER, 78.9%) compared with subjects treated once or twice (n = 36; GR to ER, 33.3%; P < .001; odds ratio, 13.68). The cryosurgical treatment was generally well tolerated, with local pain during freezing and/or shortly after treatment (n = 32, 34.4%) and hypopigmentation or hyperpigmentation (n = 11, 11.8%) being the most frequent side effects.
Conclusions: Cryosurgery was found effective and safe in keloids and, especially, in hypertrophic scars, in an open, uncontrolled study. Satisfactory results could be obtained after at least three cryosurgical sessions of 30 seconds each, applied once monthly using the contact method of treatment.