Health x Wellness

What is cryoablation?

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Breast cancer used to be a hidden disease—where women affected with it seek treatment when cancer is at a more advanced stage. This is partly due to the lack of awareness about the disease, the painless nature of (early) breast cancer lumps, the embarrassment or other social-psychological reasons.

Today, the world—survivors, family members and friends of those affected by breast cancer, as well as several organizations—comes together to actively increase breast cancer awareness in the month of October with the main theme: early detection is the best protection.

Not only is early detection of breast cancer at its early stages linked to better survival outcome, it also presents the affected women with several options of treatment. Previously, mastectomy without reconstruction was the norm. Presently, in many cases, we can conserve parts of the breast not affected by the cancer by performing lumpectomy followed by radiation therapy.

More recently, non-surgical cryoablation has been shown to be an effective alternative to lumpectomy in certain selected individuals with early breast cancer.

What is cryoablation and what is the evidence behind it?

Cryoablation is a relatively new treatment modality for early breast cancer where the cancerous cells are literally frozen to death. There is no actual surgery performed to remove that diseased breast tissue. Cryoablation uses extreme cold temperature that flows through a specialised needle, called the cryoprobe, to cause deep-freezing and destruction of the tumour by way of ice formation. No living tissue, normal or diseased, can survive such extreme temperature (–140 to -170 degree Celsius).

Evidence? A single institution study in Japan has been doing this for a selected group of early breast cancer patients for over 10 years and has shown effectiveness in achieving local control comparable to that of lumpectomy.

A multicentre trial in the USA called the ICE3 trial is ongoing and has finished their recruitment process. Last December, they reported their short-term data of 3 year follow-up with similar and promising results. At present, we are lacking long-term data of its effectiveness and hence, this treatment modality for breast cancer is still largely considered experimental or non-standard therapy.

Other uses? More studies are ongoing in Europe and Hong Kong, exploring the use of cryoablation on other more aggressive types of breast cancer or in combination with chemotherapy/immunotherapy. The idea behind this is that cryoablation is used to break up the cancer cells, making them more exposed to the effects of drugs. Cryoablation is also being investigated for use in other areas relating to breast cancer treatment, such as the use to freeze tumour metastasis to the bone. It has been reported by a European group that patients with bone metastases treated with cryoablation reported immediate relief of pain and in some cases do not require pain medications subsequently. This greatly improves patient’s quality of life.

How is it performed?

This procedure can be performed as day surgery procedure, with patients either fully awake or with moderate sedation. After local anesthesia is given to the skin, a 5 mm skin incision is made, similar to when a person undergoes breast biopsy. This incision allows the placement of the specialised needle called the cryoprobe into the tumour within the breast. The actual cryoablation procedure used in the treatment of early breast cancer involves the “freeze-thaw-freeze” cycle and the treatment time lasts about 30 minutes. At the end of the procedure, the cryoprobe is removed and the wound is closed. If the patient needs sentinel lymph node biopsy as well, that is done at the same sitting.

What can a patient expect?

If the patient is fully awake during the procedure, they will experience coolness during the procedure. The end result of the “freeze-thaw-freeze” treatment cycle is an area of dead tissue left within the treated breast—this can feel like a hard ball for the patient. Also, at the end of the procedure, the treated breast will be slightly swollen but not painful. So far, there has been no reported serious adverse effects of cryoablation for the treatment of early breast cancer. In my experience with cryoablation, patient satisfaction is high and recovery is quick. They reported feeling back to normal the next day. Your body will remove the dead tissue over time.

The bonus? Researchers believe that our immune system can become ‘activated’ because the body scavenges the remains of the dead cancer cells, including its antigen that are present on them. This may act as an ‘auto-vaccine’ against recurrence of that cancer because the immune system would be able to recognize the very same antigen now as foreign and will launch an attack when they spot them during recurrence. However, further data awaits on the confirmation of this effect.

How does cryoablation kills the tumour?
The cancer cells in immediate contact with the cryoprobe are mechanically disrupted by the formation of ice crystals that form rapidly when the probe cools during the ‘freeze’ cycle. The cells not in contact with the cryoprobe become dehydrated during the process. In the Thaw cycle, fluids rushes back into the cell that became dehydrated during the freeze cycle. This rapid expansion of the cells causes it to burst and the cell membrane is further disrupted. During the freeze cycle, the nearby blood vessels are also affected by the extreme cold temperature. The blood vessels become clotted, thereby depriving the cancer cells of blood flow and oxygen.

What happens after cryoablation?

After the procedure, the patient is discharged home on the same day. The wound heals and the swelling of the breast subsides within 1-2 weeks. The sensation of hardened tissue may continue on for months as the body removes them. There is hardly any scarring in the treated breast over time.

Cryoablation is viewed as a potential replacement for surgical lumpectomy. In terms of completeness of cancer treatment, the person deemed suitable for cryoablation must be able to undergo radiation therapy, just as a person undergoing lumpectomy would, for effective local control. Hormone therapy and chemotherapy are systemic treatments and its indication will be determined by the tumour biology and final staging.

This article is contributed by Dr Jendana Chanyaputhipoing, Breast Surgeon, PanAsia Surgery Group



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