Cryosurgery

Cryosurgery, also called cryoablation or cryotherapy, is a procedure that destroys cancer cells by freezing them. In the past, cryosurgery mainly treated tumours on the outside of the body. Today, it can also treat some tumours inside the body.

Doctors apply an extremely cold liquid or gas to tissues through a metal tube called a cryoprobe. The area is allowed to thaw and then is frozen again. The freeze-thaw cycle may need to be repeated more than once.

Liquid nitrogen is the most commonly used cryogen (a liquefied gas that produces extremely cold temperatures) to treat the outside of the body. To treat the inside of the body, argon or carbon dioxide gases may be used as cryogens instead.

Cryosurgery may be used to treat:

• skin cancer
• precancerous conditions of the skin, such as actinic keratosis
• Kaposi sarcoma
• precancerous conditions of the cervix, such as cervical intraepithelial neoplasia (CIN) and carcinoma in situ of the cervix
• prostate cancer
• verrucous carcinoma, a type of penile cancer
• precancerous conditions of the penis, such as penile intraepithelial neoplasia (PeIN) and carcinoma in situ of the penis
• retinoblastoma
• bone cancer, mostly chondrosarcoma
• liver cancer
• small renal (kidney) tumours

Your healthcare team may also use cryosurgery to remove non-cancerous growths on the skin, such as skin tags and warts.

You will usually have cryosurgery at the hospital as an outpatient (you will go home on the same day). In some cases, you will need to stay in the hospital overnight. Whether you need to stay in the hospital depends on the area being treated and your overall health.

The preparations for cryosurgery depend on the area of the body being treated and the type of anesthesia that will be used. Your healthcare team will tell you what to expect and how to prepare.

If you have cryosurgery to treat a tumour on the outside of your body, you will be given a local anesthetic to numb the area and stop you from feeling pain during the procedure. An extremely cold gas or liquid is then sprayed or applied with a swab directly to the tumour. Sometimes a cryoprobe (a metal tube holding the cryogen) is directly placed on the tumour instead. The extremely cold spray, swab or cryoprobe freezes the area and kills the cancer cells. The area is then allowed to thaw.

Sometimes, the area may need to be treated more than once to destroy the cancer. You may have multiple freeze-thaw cycles on the same day or over multiple appointments.

To treat tumours on the inside of the body, your healthcare team may do cryosurgery through a natural opening.

To treat a tumour on the cervix with cryosurgery, your healthcare team will use a speculum to widen the opening of the vagina so the cervix is easier to see. A local anesthetic may be used to numb the area with the tumour first. The cryoprobe is placed on the tumour to freeze the area and kill the abnormal cells.

To treat a tumour on the inside of the lungs with cryosurgery, you will first be given a general anesthetic. Your healthcare team will then put a bronchoscope (a flexible tube with a camera that is used to view the lungs) down your throat to see the tumour. The cryoprobe is then passed through the bronchoscope to freeze the tumour. After the freezing is complete, the area is allowed to thaw and the cryoprobe is moved to another part of the tumour. The freeze-thaw cycle is repeated to freeze the entire tumour.

When the tumour is inside the body but can't be accessed through a natural opening, the surgeon will make a small cut (incision) to reach it through the skin (called open surgery). Cryosurgery through open surgery may be done under local or general anesthesia.

An ultrasound or x-ray may be used to find the tumour and monitor the freezing process. The tip of the cryoprobe is passed through the incision to reach the tumour. A laparoscope ( a thin, tube-like instrument with a camera) is also passed through the incision to guide the cryoprobe. More than one cryoprobe may be used to treat large tumours.

The cryoprobe freezes the tumour, then the tissue is allowed to thaw and the probe is removed from the tumour. If necessary, the cryoprobe is moved and the freeze-thaw cycle is repeated to freeze the entire tumour. The frozen tissue thaws and forms scar tissue.

Side effects of cryosurgery will depend mainly on the area treated, the size of the tumour, if any surrounding tissue was damaged, and your overall health. Tell your healthcare team if you have side effects that you think are from cryosurgery. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

Some side effects of cryosurgery include:

• scarring and hypopigmentation (a loss of melanin or colour in the skin) at the area treated

• bleeding from the area treated
• pain
• swelling
• blistering
• ulcers
• infection
• nerve damage
• hypothermia

Cryosurgery for bone cancer can weaken the bones and lead to breaks in the future.

Cryosurgery on the penis or prostate may cause erectile dysfunction or incontinence. In rare cases, cryosurgery on the prostate can cause a fistula to form between the rectum and bladder. A fistula is a serious condition that needs to be treated with surgery.

Preparing children for a test or procedure by explaining what will happen during the test, such as what the child will see, feel and hear, can be very helpful. Preparing children before a test or procedure can help lower their anxiety, make them more cooperative and develop their coping skills.

How you prepare your child for cryosurgery depends on your child's age and experience. Find out more about helping your child cope with tests and treatments.

To make the decisions that are right for you, you can ask your healthcare team questions about cryosurgery.