E1735. Breast Cryoablation Procedures, Imaging Follow-up and Rad-Path Correlation
  1. Nicholas Pigg; Warren Alpert Medical School of Brown University
Breast cryoablation is a viable option for the treatment of properly selected breast cancers with post-treatment follow-up imaging and pathology being of upmost importance. Using the combination of diagnostic mammography, ultrasound and MRI, physicians are able to detect residual or recurrent malignancy and differentiate it from expected post treatment findings, before biopsied. These imaging and pathological findings must also be in concordance to differentiate the expected postprocedural histological findings from those of malignancy and determine appropriate patient treatment .

Educational Goals / Teaching Points
Introduction to Cryoablation and Mechanism of Action Procedural Technique and Imaging Follow-up Rad-Path correlation of benign and malignant post ablation findings

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Imaging is often performed at six month intervals for at least two to three years following cryoablation and annually thereafter. Mammography demonstrates a well-defined ablation zone by 1 month with a radiodense rim with internal lucency. After 12 months, any residual mass has typically resolved, being replaced by fat-density. The ablation zone progressively decreases in size and becomes less conspicuous over time. Suspicious findings on mammography include a new asymmetry, mass, architectural distortion, or suspicious calcifications located within the region of the ablation and need further imaging. Ultrasound findings follow those seen on mammography. A sonographic ablation zone becomes well-defined approximately 1 month after cryoablation, appearing as a mass of mixed echogenicity. After 6-12 months, that residual mass is no longer seen, becoming indistinguishable from the increasingly heterogeneous ablation zone. A persistent or new mass within the region of the ablation would be considered suspicious and should prompt biopsy. MRI of the breast is an important complementary imaging modality for evaluating cryoablation success. Six months after cryoablation, MRI will demonstrate the ablation zone with resolution of tumoral enhancement seen prior to the ablation procedure. Suspicious findings for recurrence on MRI include an enhancing mass in the ablation zone, new areas of nonmass enhancement, or nodular enhancement along the periphery of the ablation zone and need biopsy.

Cryoablation is a minimally invasive office-based procedure that has become more commonplace in treating early-stage breast cancer. Because there is no tissue specimen to submit to pathology, as there would be after surgical management, treating breast cancer with cryoablation highlights the importance of multi-modality post-procedure imaging follow-up in order to identify suspicious findings that might represent residual or recurrent malignancy, and thus, warrant biopsy and histologic correlation. Regardless of the imaging modality utilized, any suspicious imaging finding should undergo biopsy to distinguish residual or recurrent tumor from benign post-ablation change, such as fat necrosis. Careful attention to radiologic-pathologic correlation and determination of concordance is required to ensure optimal long-term treatment and outcomes.