This procedure is also sometimes called electrosurgery. A sharp curette is used to scrape the tumor down to its base, followed by electrodesiccation of the lesion base. Although it is a quick method for destroying the tumor, the adequacy of treatment cannot be assessed immediately since the surgeon cannot visually detect the depth of microscopic tumor invasion. Its use is limited to small (<1 cm), well-defined, and well-differentiated tumors.[Level of evidence: 3iiiDii]
Cryosurgery may be considered for patients with small, clinically well-defined primary tumors. It may be useful for patients with medical conditions that preclude other types of surgery. Contraindications include abnormal cold tolerance, cryoglobulinemia, cryofibrinogenemia, Raynaud disease (in the case of lesions on hands and feet), and platelet deficiency disorders. Additional contraindications to cryosurgery include tumors of the scalp, ala nasi, nasolabial fold, tragus, postauricular sulcus, free eyelid margin, upper lip vermillion border, lower legs, and tumors near nerves. Caution should also be used before treating nodular ulcerative neoplasia more than 3 cm in diameter, carcinomas fixed to the underlying bone or cartilage, tumors situated on the lateral margins of the fingers and at the ulnar fossa of the elbow, or recurrent carcinomas following surgical excision.
Edema is common following treatment, especially around the periorbital region, temple, and forehead. Treated tumors usually exude necrotic material after which an eschar forms and persists for about 4 weeks. Permanent pigment loss at the treatment site is unavoidable, so the treatment is not well suited to dark-skinned patients. Atrophy and hypertrophic scarring have been reported as well as instances of motor and sensory neuropathy.
The management of SCC in situ (Bowen disease) is similar to good-risk SCC. However, since it is noninvasive, surgical excision, including Mohs micrographic surgery, is usually not necessary. In addition, high complete response (CR) rates are achievable with photodynamic therapy (PDT). In a multicenter trial, 229 patients (209 evaluated in the per-protocol/per-lesion analysis) were randomly assigned to receive PDT (methyl aminolevulinate + 570-670 nm red light; n = 91), placebo cream with red light (n = 15); or treatment by physician choice (cryotherapy, n = 77; topical 5-fluorouracil, n = 26). The sustained complete clinical response rates at 12 months were 80%, 67%, and 69% in the three respective active therapy groups (P = .04 for the comparison between PDT and the two combined physician-choice groups).[Level of evidence 1iiDii] The cosmetic results were best in the PDT group. (For comparison, the CR rates at 3 months for PDT and placebo/PDT were 93% and 21%, respectively.)