What Is Cryoablation (Freezing Treatment)? Which Cancers Is It Suitable or Unsuitable For?

What Is Cryoablation?

Cryoablation is a treatment that applies an extremely cold gas or liquid to cancerous or abnormal tissue. It is one of the nonsurgical cancer treatments available. The aim is to freeze and destroy cells. Cryoablation, also called cryotherapy or cryosurgery, is used to treat certain tumors on the skin and inside the body.

The word cryoablation combines two words of Greek origin. "Cryo" derives from the Greek "krios" (κρύος), meaning "cold." "Ablation" comes from the Latin "ablatio," meaning "removal" or "extraction." In this context, cryoablation means "removal by cold" or "destruction by cold," clearly expressing the method's basic principle.

It is used to target cancer cells without damaging healthy cells and can often be performed as an outpatient or day-case treatment.

Cryoablation: Details and Procedure

Cryoablation destroys cancerous tissue by freezing it. During the procedure, a high-pressure gas or liquid passes through needles inserted into the tumor and is released at their tips. Argon gas, liquid nitrogen and liquid nitrous oxide (N2O) are most commonly used for this purpose.

A sudden drop in the pressure of gas passing through special tubes cools and freezes the tissue to minus 40-80 degrees. This process is known as the Joule-Thompson effect and causes an iceball to form around the cryoablation needle. This iceball causes widespread tissue death through the formation of ice crystals in the tumor, blockage of blood vessels and programmed cell death (apoptosis) .

The needles inserted into the tumor during cryoablation are called "probes" or "cryoprobes." Cryoprobes are straight needles with a finer internal channel through which these special high-pressure gases pass. Each needle can create an ablation zone, or area of tumor destruction, measuring 2-3 cm. For large tumors, more needles can enlarge and reshape the ablation zone. For example, an ablation diameter of around 2 cm with one needle can reach 5 cm with 4 needles, potentially allowing large tumors to be treated. Up to 25 cryoprobes can be connected simultaneously to current cryoablation devices, enabling interventional ablation of very large tumors.

The image above shows cryoablation treatment of kidney tumors. Argon gas is delivered to the tumor through special tubes, rapidly freezing the tissue and killing tumor cells. The procedure is guided by computed tomography (CT), allowing accurate needle placement and targeting of the treatment area.

Uses of Cryoablation

Cryoablation is most commonly used for early-stage prostate cancer and kidney cancer. However, after weighing its advantages and disadvantages, it can also be used for tumors in various organs and soft tissues, including lung cancer and metastases . Cryoablation offers a minimally invasive option, particularly for patients in whom surgery is difficult or risky.

Which Cancers or Conditions Can Be Treated with Cryoablation?

Cryoablation destroys cancer cells or other abnormal cells and may be used to treat a range of conditions:

• Noncancerous skin growths such as warts, skin tags or skin nodules
• Precancerous skin conditions such as actinic keratosis
• Skin cancer
• Small kidney tumors
• Prostate cancer
• Precancerous conditions of the penis, such as penile carcinoma in situ
• Penile cancer of the verrucous carcinoma type
• Primary liver cancer (hepatocellular carcinoma)
• Kaposi sarcoma
• Cervical cancer precursors, CINs
• Retinoblastoma
• Early-stage breast cancer in older people
• Bone cancer

Specialists may also favor cryoablation in the following situations:

• When the cancer does not respond to standard treatments
• When the tumor cannot be removed surgically or surgery is not a safe option
• When cancer recurs after radiotherapy
• For some cancers, in metastatic tumors

Cryoablation may also be combined with other cancer treatments, such as surgery and radiotherapy, to reduce the risk of tumor recurrence.

When Should Cryoablation Not Be Used?

Cryoablation may not be appropriate for every cancer type or every patient. For example:

1. When Surgery Is an Option: If a patient with early-stage breast cancer can undergo surgery, surgery should be preferred to cryoablation. However, cryoablation may be suitable if advanced age or other medical conditions prevent surgery.
2. Multiple Metastases: Cryoablation is unsuitable for patients with numerous metastases because not all of them can be treated with the procedure.
3. Aggressive, Fast-Growing Cancers: Cryoablation is generally unsuitable for aggressive, fast-growing cancers such as small cell lung cancer. Its effect may be limited because these cancers spread rapidly.
4. Blood Cancers: Cryoablation is not used for blood cancers such as leukemia and lymphoma. These cancers are liquid tumors distributed widely throughout the body, making cryoablation ineffective.
5. Large Tumors: Tumors larger than 6 cm may be unsuitable for cryoablation. Complete destruction of large tumors can be difficult, and surgery or other ablation methods may be preferred.

It is wrong to assume that cryoablation can be used for every cancer or metastasis, or that it is better than surgery. Cryoablation does not allow tissue to be removed and sent for pathological examination. It therefore does not permit detailed pathological and genetic analysis or assessment of whether cancer cells remain at the treatment margins. When planning cryoablation, each patient's situation should be assessed individually to select the most suitable treatment. Factors such as general health, tumor location, size and extent of spread must be considered.

An Example of Cryoablation: Treating Lung Tumors

Over the past twenty years, cryoablation has been used successfully for primary lung tumors and tumors that have metastasized to the lungs. Two-year local progression-free survival rates range from 60.7% to 100% in early-stage non-small cell lung cancer, and from 45.6% to 80.4% in secondary tumors with a small number of lung metastases.

How Is Cryoablation Performed?

Cryoablation procedures vary according to the condition, the area of the body being treated and the type of anesthesia used.

External Cryoablation

To treat a skin tumor or abnormal growth, the area is numbed with local anesthesia. A cryoprobe—a thin metal tube containing an extremely cold liquid or gas—can then be applied directly to the area to freeze and kill the cells. In some cases, the liquid or gas is applied with a swab or sprayed onto the area. After the area thaws, the specialist freezes it again, repeating this process several times.

Cryoablation Inside the Body

Internal cryoablation can be performed through a natural opening, such as accessing the cervix through the vagina, or through a small surgical incision. Whether local or general anesthesia is used depends on the individual's condition.

The procedure can be monitored using imaging equipment such as ultrasound or computed tomography (CT). The cryoprobe tip is inserted through the opening, and a thin camera-equipped tube called a laparoscope may also be introduced. More than one cryoprobe can be used for a large tumor. As with external treatment, the specialist freezes the area again after it thaws, repeating the process several times.

How Should You Prepare for Cryoablation?

Imaging scans may be needed before the procedure. Depending on the area being scanned, specific instructions may need to be followed, such as having a full bladder or not eating beforehand.

You must also tell your doctor about any medicines or supplements you take before the procedure. If you take a blood thinner, you may be asked to stop it.

Recovery After Cryoablation

People undergoing external cryoablation can usually go home after treatment. Depending on the procedure, if a surgical incision and general anesthesia were used, a hospital stay of at least 4 hours after waking may be needed until the person feels well. Painkillers can be given if necessary. Discharge is usually on the same day or the following day.

How Successful Is Cryoablation?

Success rates vary when cryoablation is used to treat specific cancers and precancerous conditions. It can be combined with other treatments such as chemotherapy and radiotherapy. It may not be suitable for every stage or tumor type.

More research is needed to determine the long-term effects of cryoablation in various cancerous and precancerous conditions.

Current research reports a success rate above 90% at the site treated with cryoablation :

• A 96% to 98% success rate in a 2018 study of people with kidney cancer
• A 90% success rate in a 2022 study of liver tumors
• A 75.9% success rate for early-stage breast cancer tumors smaller than 2 cm in an older study from 2016
• A 69% to 83% success rate for actinic keratosis, depending on freezing duration
• An 85% to 90% success rate in destroying abnormal cervical cells

What Are the Risks of Cryoablation?

The risks of cryoablation vary with the treatment site and the type and severity of the condition being treated. Possible risks include:

• Infection
• Pain
• Bleeding from the treatment site
• Swelling
• Ulcers
• Blisters
• Scarring
• Hypothermia
• Nerve damage

Other risks include side effects in particular areas of the body:

• Bones: Cryoablation can damage and weaken bone tissue.
• Cervix: Treating abnormal cervical cells with cryoablation can cause bleeding, cramps and pain.
• Liver: Cryoablation of the liver can damage its blood vessels and bile ducts.
• Skin: Treating skin tumors with cryoablation can cause nerve damage, hypopigmentation, swelling and scarring.
• Prostate: Cryoablation of the prostate can cause urinary incontinence, impotence, rectal injury and urinary obstruction.

Frequently Asked Questions About Cryoablation

1. How long does cryoablation take?
   • Procedure duration varies with the condition being treated, the size of the tumor or treatment area and the part of the body involved. Treatment may take a few minutes or several hours.
2. When does the effect of cryoablation wear off?
   • Cryoablation kills cells, so those cells cannot grow back. However, some abnormal cells may remain and spread. Researchers have found pain relief lasting 5 to 8 weeks after cryoablation in certain types of painful tumors.

Cryoablation at a Glance

Cryoablation is a procedure that uses an extremely cold gas or liquid to freeze and kill cancerous or abnormal cells.

It can be used to treat various cancers, including skin, kidney and prostate cancer. It can also treat noncancerous skin growths such as warts, skin tags or skin nodules.

Cryoablation can cause side effects such as bleeding, infection and hypothermia.

Cryoablation is highly effective for certain conditions, but it is important to remember that it is not suitable for every cancer situation.