During cryosurgery, a local anesthetic may be used to numb the treated area to prevent any discomfort or pain. If the procedure is used to treat an internal area, your doctor will use a flexible tube (called a cryoprobe) and inserts it into your body through the rectum, urethra, or surgical incisions to deliver liquid nitrogen, then the liquid nitrogen is applied to the targeted cells to freeze and destroy it. If it is used to treat external areas such as the skin, a spraying device or a cotton swab is used to apply the liquid nitrogen directly to the cancer cells.