Changes in Normal Liver and Spleen Volume after Radioembolization with 90Y-Resin Microspheres in Metastatic Breast Cancer Patients: Findings and Clinical Significance

Abstract

In clinical trials with yttrium-90-resin-microspheres for the management of colorectal cancer liver metastases, it was observed that radioembolization might result in splenomegaly and an increase in portal vein size. Subclinical hepatitis in normal liver tissue as well as the effects of radioembolization and prior chemotherapy are suspected to be responsible for this phenomenon. The purpose of this study was to quantify the changes in liver and spleen volume and portal vein diameter after radioembolization. Twenty-seven patients with liver-dominant metastatic disease from breast cancer who had not responded to chemotherapy or had to abandon chemotherapy because of its toxic effects were evaluated. Changes in liver and spleen volume and portal vein diameter as well as liver tumor volume and diameter were quantified using computed tomography scans. Radioembolization was associated with a significant mean decrease in the whole liver volume of 10.2% (median 16.7%; P=0.0024), mainly caused by a reduction in the right lobe volume (mean 16.0%; P<0.0001). These changes were accompanied by a significant increase in the diameter of the main portal vein (mean 6.8%; P<0.0001) as well as splenic volume (mean 50.4%; P<0.0001). Liver-tumor volume and diameter decreased by a median of 24 and 39.7%. Radioembolization is an effective treatment for tumor size reduction in patients with breast cancer liver metastases. Treatment is associated with changes of hepatic parenchymal volume, splenic volume, and portal vein size that appear not to represent clinically important sequelae in this patient cohort.