Description

(Source: eMedicine) Cryotherapy, also known as cryosurgery, is a commonly used in-office procedure for the treatment of a variety of benign and malignant lesions. In a recent report, cryotherapy was the second most common in-office procedure after skin excision. The mechanism of destruction is necrosis, which results from the freezing and thawing of cells. Treated areas reepithelialize. Adverse effects are usually minor and short-lived.

Dermatologists have used cryotherapy since the turn of the century. After the development of the vacuum flask to store subzero liquid elements, such as nitrogen, oxygen, and hydrogen, the use of cryotherapy dramatically increased. By the 1940s, liquid nitrogen became more readily available, and the most common method of application was by means of a cotton applicator. In 1961, Cooper introduced a closed-system apparatus to spray liquid nitrogen. In the late 1960s, metal probes became available. By 1990, 87% of dermatologists used cryotherapy in their practice. The general advantages of cryotherapy are its ease of use, its low cost, and its good cosmetic results. Most skin cancers are treated with excision or other destructive procedures, such as electrodesiccation and curettage. Superficial basal cell skin cancers and Bowen disease can be treated with cryotherapy.

Recurrence rates for primary basal cell carcinoma vary with treatment modality. The 5-year recurrence rate for cryotherapy may be as low as 7.5% if lesions are chosen judiciously. This percentage compares favorably with published recurrence rates following other procedures. Published rates include surgical excision, 10.1%; curettage and electrodesiccation, 7.7%; radiation therapy, 8.7%; and all non-Mohs modalities, 8.7%. Because these percentages are derived from various studies, rather than one randomized controlled study comparing the different modalities, they should be viewed as rough approximations. Well-circumscribed tumors are most suitable for cryotherapy. The indolent local growth of these well-circumscribed tumors accounts for the high cure rates quoted in the literature.