Liver Metastases in the Era of Molecular Targeted Therapy: New Faces of Treatment Response

Abstract

In the era of molecular targeted therapy, every radiologist who interprets oncologic studies needs to be aware of the unusual patterns of treatment response and should be able to differentiate pseudoprogression of liver metastases from true progression because this distinction has an important impact on clinical management.

Anti-VEGF Molecular Targeted Therapies in Common Solid Malignancies: Comprehensive Update for Radiologists

“…Both bevacizumab and conventional chemotherapeutic regimens alter the morphologic characteristics of tumors, affecting overall heterogeneity, enhancement, and distinctness of margins, in addition to size (16,39,40) (Fig 4). These morphologic changes correlate with replacement of tumor tissue by fibroconnective tissue (16).…”

“…These patterns are being increasingly recognized and are a potential source of confusion and challenge for the radiologist (40). Treatment with antiangiogenic MTTs can unmask previously isoattenuating liver lesions that become apparent after treatment due to the decrease in attenuation (Fig 7).…”

“…Discussion with the treating oncologist and correlation with the clinical status of the patient and tumor markers, together with follow-up imaging, can help differentiate pseudoprogression from true progression (40). Commonly used tumor markers include carcinoembryonic antigen (CEA) in colorectal cancer, a-fetoprotein (AFP) in HCC, serum prostate-specific antigen (PSA) in prostate cancer, chromogranin A in neuroendocrine tumors, cancer antigen (CA) 19-9 in pancreatic cancer, CA-125 in ovarian cancer, and CA 27-29 in breast cancer.…”

Esophageal Carcinoma: Current Concepts in the Role of Imaging in Staging and Management

“…Axial contrast-enhanced computed tomography image demonstrates heterogeneous metastatic deposit in a right lower rib as well as ascites consistent with peritoneal carcinomatosis. and development of sharp tumour-liver interface with or without concurrent changes in size [38]. These atypical changes of treatment response may be expected to increase in the future due to the anticipated increase in the molecular targeted therapies in the future.…”

Update on the Role of Imaging in Management of Metastatic Colorectal Cancer

“…In our experience, three such patterns of "pseudoprogression" can occur (50). First, lesions that were isoattenuating on pretreatment scans tend to become apparent on posttreatment scans because they become hypoattenuating and can therefore be misinterpreted as new lesions.…”