What is cryosurgery?
Cryosurgery (also known as cryotherapy) involves the use of extreme cold produced by liquid nitrogen (or argon gas) to destroy abnormal tissue. Cryosurgery is used to treat external tumors on the skin. For external tumors, liquid nitrogen is applied directly to the cancer cells with a cotton swab or spray device.
The most common uses for cryosurgery are to treat acne, seborrheic keratosis, and actinic keratosis. It is also used for pimples, scars, small benign growths, and some skin cancers. Older dermatologists still use cleansers to apply it, but the result is the same.
Why cryosurgery is done?
Cryosurgery is mainly used to treat:
- Actinic keratosis (a precancerous situation of the skin)
- Skin cancer
- Precancerous diseases of the cervix such as cervical intraepithelial neoplasia (CIN) and carcinoma in situ of the cervix
- Hepatocellular carcinoma (a sign of liver cancer) – when surgery is not feasible
- Cancer that has grown to the liver from different part of the body (called liver metastases)
- Retinoblastoma (a type of childhood eye cancer)
Types of cryotherapy
There are two types of cryotherapy.
- Whole-prostate cryotherapy: Treats the entire prostate with a combination of cancer cells and healthy prostate tissue.
- Focal cryotherapy: It only treats a part of the prostate that has cancer. It uses fewer needles, which means less freezing of healthy tissue than full prostate cryotherapy.
Focal cryotherapy is not suitable for all men. It depends on the size of your cancer and its location in the prostate.
Risks of surgery are rare, but can include:
- Cervical stenosis (less than 1% risk), which makes it difficult to get pregnant or causes more numbness over time.
Cryosurgery is performed intraoperatively, endoscopically, or percutaneously, depending on the location and size of the tumor. This is done using an argon-helium system. Two to three freeze/thaw cycles are performed. The “ice ball” formed at the tip of the cryoprobe continues to clot until the tumor is large enough. A margin of normal tissue of 5 to 10 mm is added during the coagulation process.
For larger tumors, multiple cryoprobes were used. In some cases, it may be necessary to perform at least 2-3 sessions of the cryoablation procedure. This is possible because the procedure is minimally invasive and does not require frequent cuts. The probes are simply inserted through the skin and guided by ultrasound or CT in real-time.
In cryosurgery, the tissue is frozen with a cryosurgical probe, which produces better thermal contact with undesirable tissue. Several minutes after the start of cooling, the temperature phase of the tissue associated with the probe reaches the transition temperature and the tissue begins to freeze. As more heat builds up, the probe temperature drops, and the freezing interface begins to extend from the probe into the tissue. Variable temperature distribution occurs in frozen and unfrozen regions of tissue.
In general cryosurgical protocols, the cooling system freezes the tissue at the desired time after freezing, followed by heating and thawing. Cells close to the surface of the cryosurgical probe are cooled at a higher cooling rate and lower temperatures than those far from the probe. Cells located in different places in the frozen lesion are at different temperatures at different times, their distance from the probe surface, the working coolant, the shape of the cryosurgical probes, the number of cryosurgical probes used, the type of tissue frozen.
Cell damage while cooling and coagulation occur on certain length scales: nanoscale (Armstrong) – molecular, mesoscale (micron) – cellular, and macroscale (millimetre) – entire tissue. There are two types of damage during cryosurgery, severe, immediate during cryosurgery, and chronic.
Advantages of cryosurgery
- Cryotherapy bleeds less or less than some other treatments.
- You will only be in the hospital for a day or overnight.
- Recovery is usually quick and most men will return to normal activities within a few weeks.
- If your cancer comes back after radiation therapy or brachytherapy, you may receive cryotherapy.
- If your cancer comes back after your first cryotherapy treatment, you can go back to cryotherapy. This is not the case for all treatments.
The main disadvantage of cryosurgery is the uncertainty surrounding its long-term impact. Cryosurgery can be effective in treating tumors that a doctor can see using imaging tests (tests that produce images of areas inside the body), but this eliminates the spread of microscopic cancer. Also, as the impact of the technology is still being evaluated, insurance coverage issues may arise.
Side effects of cryosurgery
- Swelling and redness
- Hypertrophic/keloid scarring
- Pigmentation changes
Complications of cryosurgery
- Loss of sensation in the treatment area for 12 to 18 months
- Loss of pigmentation
- Loss of hair in the treatment area
- Bleeding and blisters
- Healing problems
Departments to consult for this condition
- Department of dermatology