Percutaneous cryoablation could potentially be used as a last line of defense to halt individual spots of remaining metastatic breast cancer by freezing and destroying tumours, according to study presented at the Society of Interventional Radiology’s 37th Annual Scientific Meeting in San Francisco, USA.
“If you envision cancer treatment as a three-legged stool: you have radiation therapy, surgery and chemotherapy. When you get to the point of metastatic disease, you end up managing people whose treatments have failed. We are introducing the fourth leg on the stool of cancer care: tumour ablation,”said Peter J Littrup, director of Imaging core and radiology research, Karmanos Cancer Institute, Detroit, Michigan, USA.
“Stage IV metastatic breast cancer means tumours have spread widely from the primary tumours in the breasts to other tissues of the body. This stage of disease is currently viewed as incurable and associated with a low rate of survival. While less than 5% of those are initially diagnosed with metastases, an estimated 25 to 40% will develop these additional tumours, which are notoriously difficult to wipe out, even with multiple forms and repeated rounds of treatment,” said Littrup.
“At this point, treatments are considered palliative—with the intent to keep metastases at bay while hopefully providing individuals more time and improved quality of life, rather than a complete cure. But after mastectomy, radiation and chemotherapy, it is time to try something new,” he added.
“Why should people have to keep changing from one expensive chemo drug to another when there are just a few remaining spots?” said Littrup. “Cryoablation could offer these individuals a new treatment option.”
“Cryoablation as a targeted therapy is beneficial because it can significantly reduce discomfort and incidence of disease,” said Littrup. “It is a much better option, we think, than surgery, especially since many metastatic patients are not candidates for surgery, and it may potentially lead to longer survival if it coincides with more data concerning primary metastases in other regions of the body,” he said.
The study set out to assess complications, local tumour recurrences, and overall survival after percutaneous cryoablation of metastatic breast cancer. For the study, a total of eight people with nine tumours received percutaneous cryoablation procedures guided with CT, ultrasound or a combination of both methods. Six of the eight subjects had formerly undergone at least a single mastectomy prior to treatment with percutaneous cryoablation. The secondary tumours of these people were found in the liver, lung and kidney. Complications were assessed according to Common Toxicity Criteria for Adverse Events Version 3.0 (CTCAE). Median survival was given from the time of stage IV diagnosis until percutaneous cryoablation in addition to survival time afterward in order to assess the adjunctive role of percutaneous cryoablation.
A mean of 1.1 percutaneous cryoablations per patient were performed. There were no major complications and zero local recurrences occurring in this study. The median overall survival from time of stage IV diagnosis was 3.8 years (46 months) with an observed 5-year survival rate of 25%. Average time from stage IV diagnosis until percutaneous cryoablation was 16 months and average survival after treatment was 30 months.
“This is a preliminary study, and at this point we are hoping that the evidence could be a stepping stone for a bigger study to look at more patients. If we can get more data that supports percutaneous cryoablation for metastatic breast cancer, it could be a huge finding,” Littrup added.