Cryosurgery in Cancer Treatment

by National Cancer Institute

Key Points

• Cryosurgery is a technique for freezing and killing abnormal cells. It is used to treat some kinds of cancer and some precancerous or noncancerous conditions, and can be used both inside the body and on the skin.

• Cryosurgery is an alternative to surgery for liver cancer that has not spread, for cancer that has spread to the liver from another site, for prostate cancer confined to the prostate gland, for a precancerous condition of the cervix, and for cancerous and noncancerous tumors of the bone.

• Cryosurgery may have fewer side effects than other types of treatments, and is less expensive and requires shorter recovery times.

• The technique is still under study, and its long-term effectiveness is not known.

What is cryosurgery?

Cryosurgery (also called cryotherapy) is the use of extreme cold produced by liquid nitrogen (or argon gas) to destroy abnormal tissue. Cryosurgery is used to treat external tumors, such as those on the skin. For external tumors, liquid nitrogen is applied directly to the cancer cells with a cotton swab or spraying device.

Cryosurgery is also used to treat tumors inside the body (internal tumors and tumors in the bone). For internal tumors, liquid nitrogen or argon gas is circulated through a hollow instrument called a cryoprobe, which is placed in contact with the tumor. The doctor uses ultrasound or MRI to guide the cryoprobe and monitor the freezing of the cells, thus limiting damage to nearby healthy tissue. (In ultrasound, sound waves are bounced off organs and other tissues to create a picture called a sonogram.) A ball of ice crystals forms around the probe, freezing nearby cells. Sometimes more than one probe is used to deliver the liquid nitrogen to various parts of the tumor. The probes may be put into the tumor during surgery or through the skin (percutaneously). After cryosurgery, the frozen tissue thaws and is either naturally absorbed by the body (for internal tumors), or it dissolves and forms a scab (for external tumors).

What types of cancer can be treated with cryosurgery?

Cryosurgery is used to treat several types of cancer, and some precancerous or noncancerous conditions. In addition to prostate and liver tumors, cryosurgery can be an effective treatment for the following:

• Retinoblastoma (a childhood cancer that affects the retina of the eye). Doctors have found that cryosurgery is most effective when the tumor is small and only in certain parts of the retina.

• Early-stage skin cancers (both basal cell and squamous cell carcinomas).

• Precancerous skin growths known as actinic keratosis.

• Precancerous conditions of the cervix known as cervical intraepithelial neoplasia (abnormal cell changes in the cervix that can develop into cervical cancer).

Cryosurgery is also used to treat some types of low-grade cancerous and noncancerous tumors of the bone. It may reduce the risk of joint damage when compared with more extensive surgery, and help lessen the need for amputation. The treatment is also used to treat AIDS-related Kaposi's sarcoma when the skin lesions are small and localized.

Researchers are evaluating cryosurgery as a treatment for a number of cancers, including breast, colon, and kidney cancer. They are also exploring cryotherapy in combination with other cancer treatments, such as hormone therapy, chemotherapy, radiation therapy, or surgery.

In what situations can cryosurgery be used to treat prostate cancer? What are the side effects?

Cryosurgery can be used to treat men who have early-stage prostate cancer that is confined to the prostate gland. It is less well established than standard prostatectomy and various types of radiation therapy. Long-term outcomes are not known. Because it is effective only in small areas, cryosurgery is not used to treat prostate cancer that has spread outside the gland, or to distant parts of the body.

Some advantages of cryosurgery are that the procedure can be repeated, and it can be used to treat men who cannot have surgery or radiation therapy because of their age or other medical problems.

Cryosurgery for the prostate gland can cause side effects. These side effects may occur more often in men who have had radiation to the prostate.

• Cryosurgery may obstruct urine flow or cause incontinence (lack of control over urine flow); often, these side effects are temporary.
• Many men become impotent (loss of sexual function).
• In some cases, the surgery has caused injury to the rectum.

About the Author

www.nci.nih.gov
The National Cancer Institute's research programs are extensive and contain many innovative initiatives. I invite you to explore our Web site to find out more about the exciting work being conducted here at NCI and by NCI-supported scientists throughout the country.