Cryotherapy, also known as cryosurgery, is a commonly used in-office procedure for the treatment of a variety of benign and malignant lesions. In one report, cryotherapy was the second most common in-office procedure after skin excision. The mechanism of destruction in cryotherapy is necrosis, which results from the freezing and thawing of cells. Treated areas reepithelialize. Adverse effects of cryotherapy 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 and
Lee 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.
The spray cryotherapy technique is probably the most commonly used method. This method is suitable for most benign and some superficial neoplastic lesions.Pulsing each spray to avoid an overexpansion of the treatment site prevents complications.
A cone spray technique, as shown in the image below, has been suggested in the past by using an apparatus with 2 open ends; however, such accessories are not readily available and, thus, they are not often used. The cone attachments are round; therefore, they are most suitable for round lesions. For large, irregularly shaped lesions, sequential freezing is necessary.
The use of disposable specula instead of nondisposable cone attachments offers several advantages. Disposable specula, as shown in the image below, can be cut with scissors to vary the size and the shape of the aperture. With the advent of HIV and other communicable diseases, the use of a disposable device, such as the plastic specula, is a convenient and simple solution to the problem of contamination