Liver Metastases in High-grade Neuroendocrine Neoplasms: A Comparative Study of Hepatic Tumor Volume and Biochemical Findings in NET G3 Versus NEC

Abnormal liver blood tests and liver tumor burden are known prognostic factors in neuroendocrine neoplasms (NEN). However, the relationship between biochemical liver parameters and hepatic tumor load is largely unknown in NEN and in high-grade NEN (G3) specifically. The primary objective of this study was to correlate the biochemical parameters and liver tumor volume of patients with neuroendocrine tumors grade 3 (NET G3) or neuroendocrine carcinomas (NEC). We wanted to investigate whether patients with NET G3 with extensive liver involvement had less severely elevated laboratory liver parameters than NEC patients. In total, 46 patients with NEN were included, 31 had NEC and 15 NET G3. All patients had distant metastatic disease, with liver metastases being the most common (n = 39). Both laboratory results and semiautomatic volumetric measurements of liver tumor burden were obtainable for 34 patients at baseline and 26 patients at follow-up. Alkaline phosphatase (AP), gamma-GT (gGT), and lactate dehydrogenase (LDH) increased significantly between the two time periods (p < .01). In a regression model, liver tumor burden significantly affected several blood parameters, for example, increasing AP, gGT, LDH, and aspartate aminotransferase (ASAT) by a factor of 1.02-1.04 per unit increase (1% tumor burden; all p < .001). AP, gGT, and LDH were significantly lower in NET G3 (factor of 0.43-0.68) than in NEC. Here, we found that liver chemistries changed over the NEN disease course, correlated with hepatic tumor burden, and differed by histologic subtype. The current data can potentially guide treatment decisions, for example, with regard to integration of liver-directed therapies.