Diagnostic radiologist, Dr Peter Schoub, educates us on the latest treatment option for small breast cancers: cryoablation.
What is cryoablation?
Ablation means destroying tissue and cryo means cold or freezing. Thus, cryoablation is the freezing of tumours to destroy them.
How does it work?
The freezing is achieved with liquid nitrogen which flows through a probe (needle). The needle is inserted into the tumour under ultrasound guidance. This allows us to position it very precisely, ensuring that the tumour is at the centre of the freezing zone.
The liquid nitrogen never leaves the needle, but it causes the tissue around the needle tip to freeze rapidly. This creates a large ball of ice that engulfs the tumour. By alternating freeze and thaw cycles, the cells in the tumour are destroyed.
By the end of the procedure, there should be no viable cancer cells left. The progress of ice ball development is closely monitored throughout the procedure to ensure safety.
The procedure is performed after the administration of local anaesthetic. The skin and deeper tissues are completely numbed prior to the introduction of the cryoablation needle. It’s therefore a painless procedure. Cryoablation of a breast tumour takes 30 to 40 minutes. Patients can go home soon thereafter.
What are the side effects?
Since cryoablation involves tissue destruction, patients can expect to develop bruising of the breast that lasts for one to two weeks. Post procedure pain is usually mild and can be controlled with anti-inflammatories and paracetamol.
A palpable lump remains at the tumour site after cryoablation. This is scar tissue that forms after tumour destruction. It will resolve within six to 12 months.
There have been few complications from this procedure. The most significant complication is frostbite of the skin overlying the ice ball. For this reason, particular care is given to maintaining good distance between skin and ice during procedure. Other complications, such as bleeding, are rare or minor.
Cryoablation in breast cancer treatment
The purpose of cryoablation is to offer an alternative to surgery for selected breast cancers. Cryoablation replaces lumpectomy but doesn’t remove the need for supplementary treatments prescribed by your oncologist. Most patients will still need to be on chronic endocrine treatment, such as tamoxifen, following procedure. The purpose is to prevent a recurrence.
Some patients may also need radiotherapy following cryoablation, as they would if they had undergone lumpectomy.
Follow-up studies with mammograms, ultrasound and MRI confirm the absence of any residual breast cancer.
Who can opt for cryoablation?
Cryoablation is an excellent option for patients who have contraindications to surgery.
It’s also being used for patients who have metastatic (Stage 4) breast cancer. Treating the tumour in the breast is thought to induce an immune response that may act on the metastatic lesions in other parts of the body.
The decision to perform cryoablation is taken by the patient in consultation with treating doctors. The patient must have a tumour that fits the criteria listed below.
Cryoablation will not be successful if used inappropriately.
A radiologist may perform the procedure as it’s an image-guided ablation. Radiologists, experienced in other ultrasound guided techniques, such as biopsies, are well-suited to perform image-guided cryoablation. However, all referrals must be from a surgeon or oncologist.
Tumours suitable for cryoablation
- Solitary tumours.
- <2cm maximum diameter.
- No lymph node spread.
- Tumour not too close to skin or chest wall.
- Hormone cancers (other cancer types may be considered in the metastatic setting).
Tumours not suitable for cryoablation
- Multiple tumours.
- >2cm maximum diameter.
- Tumours associated with lymph node metastases.
- Tumours abutting skin or chest wall.
- Non-hormone cancers i.e. HER-2 and triple negative cancers (exception may be for Stage 4 disease).
- Ductal carcinoma in situ (DCIS).
Advantages over surgery
- No hospital admission. This means reduced costs and infection exposure.
- No general anaesthesia.
- Quicker recovery.
- Usually minimal post procedure discomfort.
- Excellent cosmetic outcome.
International experience and clinical trials
Cryoablation was developed as a treatment for breast cancers around 15 years ago. There have been three large clinical trials (two of which are ongoing) and multiple smaller studies.
Internationally, there is considerable experience with cryoablation of fibroadenomas of the breast.
In the last 10 years, there is growing evidence for effective cryoablation of small malignant carcinomas of the breast. All the published results show >95% successful ablation in tumours smaller than 1,5cm. There is almost universal agreement that for smaller breast lesions (<1,5cm), cryoablation results in complete tumour destruction and negligible recurrence in the first three to five years.
In the USA, there is FDA approval for treatment of fibroadenomas and cancers (on and off trial).
For more info, please visit cryoablation.co.za
MEET THE EXPERT – Dr Peter Schoub
Dr Peter Schoub is a radiologist at Parklane Women’s Imaging Centre. He obtained the European Diploma of Breast Imaging in 2018 and is an honorary lecturer in the department of Radiology at the University of the Witwatersrand.