Cryotherapy Health Article

Definition

Cryotherapy is a technique that uses an extremely cold liquid or instruments to freeze and destroy abnormal or cancerous skin cells that require removal. The technique has been in use since the turn of the century, but modern techniques have made it widely available to dermatologists and primary care doctors. Recent advances have also lead to more use of cryotherapy in treating internal cancer. The technique is also called cryosurgery.

Purpose

Cryotherapy can be employed to destroy a variety of benign skin growths, such as warts, precancerous lesions (such as actinic keratoses), and malignant lesions (such as basal cell and squamous cell cancers). It has also found new use in treating internal cancers, such as cancers of the prostate gland and the breast. The goal of cryotherapy is to freeze and destroy targeted skin growths or cancers while preserving the surrounding tissue from injury.

Precautions

Cryotherapy is not recommended for certain areas of the body because of the danger of destruction of normal tissue or unacceptable scarring. These areas include: skin that overlies nerves, the corners of the eyes, the fold of skin between the nose and lip, the skin surrounding the nostrils, and the border between the lips and the rest of the face. Lesions that are suspected or known to be malignant melanoma, an aggressive form of skin cancer, should not be treated with cryotherapy, but should instead be removed surgically. Similarly, basal cell or squamous cell skin cancers that have reappeared at the site of a previously treated tumor should also be removed surgically.

If it remains unclear whether a growth is benign or malignant, a sample of tissue should be removed for analysis (biopsy) by a pathologist before any attempts to destroy the lesion with cryotherapy. Care should be taken in people with diabetes or certain circulation problems when cryotherapy is considered for growths located on their lower legs, ankles, and feet. In these patients, healing can be poor and the risk of infection can be high.

Description

There are three main techniques used to perform cryotherapy. In the simplest technique, usually reserved for warts and other benign skin growths, the physician will dip a cotton swab or other applicator into a cup containing a "cryogen, " such as liquid nitrogen, and apply it directly to the skin growth to freeze it. At a temperature of 320°F (-196°C), liquid nitrogen is the coldest cryogen available. The goal is to freeze the skin growth as quickly as possible, and then let it thaw slowly to cause maximum destruction of the skin cells. A second application may be necessary depending on the size of the growth.

In another cryotherapy technique, a device is used to direct a small spray of liquid nitrogen or other cryogen directly onto the skin growth. Freezing may last from 20-30 seconds, depending on the size of the lesion. A second freeze-thaw cycle may be required. In a third option, liquid nitrogen or another cryogen is circulated through a probe to cool it to low temperatures. The probe is then brought into direct contact with the lesion, either on the skin or in the case of internal cancers, inside the patient. The freeze time can take two to three times longer than with the spray technique.

Preparation

Extensive preparation prior to cryotherapy is not required for external lesions. The area to be treated should be clean and dry, but sterile preparation is not necessary. Patients should know that they will experience some pain at the time of the freezing, but local anesthesia is usually not required. The physician may want to reduce the size of certain growths, such as warts, prior to the cryotherapy procedure, and may have patients apply salicylic acid preparations to the growth over several weeks. Sometimes, the physician will pare away some of the tissue using a device called a curette or a scalpel.

Preparation for treating cancers inside the body, such as prostate cancer, is slightly more complicated. The areas that are to be cooled are precisely mapped using ultrasound imaging or a specialized x-ray machine known as a computed axial tomography (CAT) scan. Temperature sensors are then placed inside and around the tumor to monitor the temperature. Lastly, cooling probes are then placed in and around the tumor.

Risks

Cryotherapy poses little risk and can be well tolerated by elderly and other patients who are not good candidates for other surgical procedures. As with other surgical procedures, there is some risk of scarring, infection, and damage to underlying skin and tissue. These risks are generally minimal in the hands of experienced users of cryotherapy.