Perfusion Changes in Liver Metastases (LM) from Pancreatic Neuroendocrine Tumors (PanNETs) during Everolimus (E) Treatment: Update of Perfusion CT (P-CT) Study

Introduction: P-CT can evaluate inner perfusional features of primary and metastatic PanNETs; preliminary evidences suggest its potential role in predicting early response to anti-angiogenic thera- pies. Perfusional modifications induced by E in LM are not com- pletely understood. Aim(s): To evaluate modifications detected by P-CT in LM from PanNETs during E treatment. Materials and Methods: Seven patients with LM from G1-2 PanNETs were pro- spectively evaluated. P-CT was performed at baseline (T0), after 2 (T1) and 4 (T2) months of E. Lesion size, blood flow (BF), blood volume (BV), peak enhancement intensity (PEI) and time to peak (TTP) were calculated. Comparison between P-CT features at dif- ferent time points was performed with 2-tailed unpaired Student’s T test. Results: Eighteen LM were evaluated; 72.2% LM showed size stability during E treatment. Twelve LM (66.6%) had a significant overall decrease in BF (p = 0.002), while the remaining 6 (33.4%) had a significant increase (p = 0.007). BV significantly increased from T0 to T2 in 10 (55.5%) LM (p = 0.002); the remaining 8 LM showed a significant BV decrease (p = 0.007). 83.3% LM showed a signifi- cant PEI decrease (from T0 to T2, p = 0.001), even at an early stage (from T0 to T1, p = 0.02). TTP was not significantly modified by E. Conclusion: E treatment seems to decrease BF and PEI and increase BV in PanNETs LM. Size and TTP are not modified by E. Longer fol- low up is needed to study the correlation between perfusional modi- fications and clinical outcomes.