Topical application of a 40% hydrogen peroxide formulation appears to be less cytotoxic than cryosurgery for the treatment of seborrheic keratosis, and may present a lower risk of post-treatment pigment changes.
“Given the common nature of these growths and the frequency with which patients seek treatment for them, we wanted to clearly demonstrate at the cellular level the degree of injury and, most importantly, pigmentary changes, from both the gold standard cryosurgery and a newly approved approach, A-101 topical solution [the 40% hydrogen peroxide product],” said the paper’s senior author, Dr. Adam Friedman, in a press release. “A-101 was found to be less cytotoxic, or toxic to living cells, and less damaging to melanocytes, the cells in the skin that make pigment, than cryosurgery.”
Dr. Friedman is an associate professor of dermatology at George Washington University School of Medicine and Health Sciences in Washington, D.C.
In the paper, investigators evaluated skin architecture, metabolic activity, and cytotoxicity with an emphasis on melanocytes, using a validated ex-vivo human reconstituted full thickness skin model (MRHE). The skin models were derived from Fitzpatrick type V skin.
The MRHE were treated with cryosurgery in five- or 10-second freeze cycles, or the A-101 at 1 or 2 µL dosing. Investigators then used MTT assay, Fontana-Masson, TUNEL, and S100 immunohistocchemical staining to evaluate skin architecture, metabolic activity, and cytotoxicity.
Histologic evaluation of untreated tissue, and tissue treated with A-101 vehicle, showed normal stratum corneum, spinous, and basal cell layers over a well-organized dermis with scattered fibroblasts.
Cryotherapy-treated MRHE was found to have an overall thinning of the epidermis, with the 10-second-treated specimens having more pyknotic cells in the deeper spinous layer. Both cryosurgery groups also showed dermal-epidermal separation, though it was more prominent in the 10-second group.
Acanthosis of the epidermis and mild pallor was seen in both A-101-treated groups, though to a lesser extent than was seen in the cryosurgery groups, and without epidermal clefting.
TUNEL staining also found more apoptotic cells in the cryosurgery groups than in the A-101 groups. Cellular metabolic activity was also reduced in the cryosurgery groups compared to the A-101 groups.
“There is ongoing clinical work evaluating the safety of this solution in darker skin types,” said Dr. Friedman.
“Another important take away from this study is to also recognize how damaging even a small amount of cryotherapy, a five-second freeze time, can be to human skin. These findings should be considered when used for the broad array of skin diseases for which cryosurgery is warranted.”