Using percutaneous computed tomography-guided core needle biopsy of liver metastases from gastroenteropancreatic neuroendocrine tumors to identify inter-tumor grading classification heterogeneity

Abstract

Background We used percutaneous computed tomography-guided core needle biopsy (PCT-CNB) of liver metastases from (gastroenteropancreatic neuroendocrine tumors) GEP NETs to identify inter-tumor grading classification heterogeneity. Methods We retrospectively investigated 92 patients with liver metastases in GEP NETs using PCT-CNB; 76 patients had tissue from liver and primary sites while 16 had tissue from liver and secondary liver sites. For tissue sampling, Ki-67 immunohistochemistry was performed and grading classifications was determined. Inter-tumor grading classification heterogeneity and associated changes on patient survival were also evaluated. Results No procedure-related mortality was recorded during and after biopsy. In 37/92 patients (40.2%), grading classifications changed: 13 patients increased from G1 to G2, 2 increased from G1 to G3, 5 decreased from G2 to G1, 14 increased from G2 to G3, 1 decreased from G3 to G1, and 2 decreased from G3 to G2. Patients with NET G1 or NET G2 grades had better progression-free survival (PFS) and overall survival (OS) when compared with NET G3 grade patients (P=0.001 and P < 0.001, respectively). OS rates at 5 and 10 years were 67.5% and 26.0% for stable G2 patients, but decreased to 46.4% and 23.2% for increased G2 patients (P=0.016). Conclusion The PCT-CNB of liver metastases from GEP NETs showed grade differences between the liver tumor and primary site/secondary liver metastases. Also, when G2 increased, OS significantly decreased.

Tumour Heterogeneity and the Consequent Practical Challenges in the Management of Gastroenteropancreatic Neuroendocrine Neoplasms

“…For neuroendocrine liver metastases, FNA has been used to confirm diagnosis and to assess tumour grading [ 103 , 104 ]. In view of the increased intra- and inter-tumour heterogeneity in neuroendocrine liver metastases and the differences often seen in the primary tumour, however, biopsy is recommended, with a core needle or surgical biopsy still being the preferred modalities, as differentiation and grading have significant prognostic value in metastatic disease [ 26 , 105 , 106 ]. Nevertheless, it should be kept in mind that preoperative biopsies, both FNA and core, could wrongly assess grading in as many as a third of cases when compared with the grading seen on the surgical specimen of GEP neuroendocrine liver metastases.…”