Initial experience with contrast-enhanced ultrasonography in follow up assessment of small breast cancer treated by cryoablation

摘要

Background Cryoablation (CA) is a nonsurgical focal therapy for small tumours. To detect residual or relapsed tumour after CA of renal cancer, contrast-enhanced imaging is generally used to identify tumour blood flow, but no definitive criteria are established for such follow-up after CA of breast cancer. Aims The aim of this study was to compare the usefulness of contrast-enhanced ultrasonography (CEUS) and magnetic resonance (MR) imaging for assessing residual tumours and local relapse following CA of small breast cancers. Methods We enrolled 4 patients treated by CA at our institution between January 2015 and December 2016 for luminal A breast cancer with maximum tumour size of 1.5cm and neither distant metastasis nor metastatic findings in sentinel lymph node biopsy, who underwent CEUS and MR imaging before CA. In addition to our standard postoperative follow-up for breast cancer, these patients underwent CEUS every 3 months and MR imaging every 6 months after CA. Results Six months after CA, no patient showed enhancement at the lesion site on MR imaging, but there were two with continued enhancement on CEUS. They underwent vacuum-assisted breast biopsy under US guidance followed by histopathological examination of tissue that identified no malignancy. Conclusion Our findings of focal enhancement within ablated breast tissue in CEUS after CA is likely attributable to the much higher sensitivity of CEUS to that of other modalities to even slight vascularization. Further investigation in more patients is needed to clarify the utility of CEUS to detect residual or relapsed tumour after CA of small breast cancer.