A study from France presented at the European Congress of Radiology (ECR, 4–8 March, Vienna, Austria) has found that percutaneous thermal ablation is safe and effective for local control of metastatic breast cancer.
Investigators Matthias Barral, Department of Interventional Radiology, Institut Gustave Roussy, Villejuif, France, told delegates that in the researchers’ opinion, ablation was likely to play a major role in future treatment strategies in association with other therapies for patients with few metastatic lesions.
The researchers set out to describe the prognostic factors for the local control rate and the one- and two-year disease-free survival after percutaneous thermal ablation in patients with oligometastatic breast cancer>
Barral told Interventional News: “Treatment of oligometastatic breast cancer (less than five metastases) is currently highly challenging. Although this condition concerns just a small proportion of metastatic patients, due to refinements in new systemic chemotherapy along with specific hormonal therapy, a wider range of patients are prone to becoming oligometastatic after completion of their medical treatment. Surgery and stereotactic body radiation therapy have demonstrated their efficicacy for local ablation of breast cancer metastases and each has their own advantages and drawbacks. Regarding interventional radiology, researchers have already demonstrated that radiofrequency ablation of breast cancer liver metastases is safe and efficient for tumours smaller than 3cm with a success rate of about 90%. Recently, interventional radiology has developed a therapeutic armamentarium including microwave ablation and cryotherapy that allows increasing the possibilities of ablation to lung, bone or even to soft tissue metastases.
“The primary goal of our study was to demonstrate that interventional radiology along with systemic chemotherapy is able to manage oligometastatic breast cancer regardless of the location of the metastases. In addition, breast cancer is a very heterogeneous disease considering its histological subtype, immunological profile, progression rate, etc. Consequently, there is a need for interventional radiologists to be aware of the potential factors that might be associated with a poorer outcome in terms of local relapse or disease-free survival. As a matter of fact, the role of the interventional radiologist in the management of oligometastatic patients should not be limited to the assessment of the technical feasibility of an image-guided percutaneous ablation, it should also include the knowledge of breast cancer variety and natural history that might influence the treatment decision. With this knowledge in hand, interventional radiologist could therefore become a major player in the multidisciplinary management of oligometastatic breast cancer patients.”
The Villjeuf researchers treated nearly 80 patients with 114 breast cancer metastases involving bones, liver and lung, with a mean diameter of 28.9±16.1 mm [5–86mm] using thermal ablation only with a curative intent for all metastases.
Barral and colleagues evaluated the following prognostic factors: histological subtype, interval between diagnosis of breast cancer and ablation, diameter of each metastases at the time of treatment, sum of maximal diameter of all metastases, number of metastases, context of occurrence (synchronous, relapse after complete remission or incomplete response to systemic chemotherapy), progression despite systemic therapy and targeted organ.
“We evaluated local relapse and the one- and two-year disease-free survival on cross-sectional imaging according to the increasing in the diameter of the ablation scars, the onset of enhancement on the ablation scars and to the onset of a new metastases, respectively,” he explained.
The median follow-up was 18.4 months.
Results from the study showed that the local control rate at one and two years was 84.1% and 77.1%. Larger diameters of the metastases treated were associated with an incomplete local treatment (p=0.034). The one- and two-year disease-free survival rates were 55.4% and 31.1%. Triple negative breast cancer metastases, ie those that do not express the genes for oestrogen receptor, progesterone receptor or Her2/neu making chemotherapy more difficult, were associated with a poorer outcome. “There was no post-treatment mortality and the morbidity rate was 15% with none of the complications requiring surgical intervention,” said Barral.