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Updated: Apr 18, 2026
Treatment of Liver Metastases Using an Internal Target Volume Method for Stereotactic Body Radiotherapy
Published on: May 8, 2018
Associations between Patterns of Neuroendocrine Liver Metastatic Burden and Outcomes after Liver-Directed Therapy,
Cathal O Apos Leary1, David James Tischfield2, Rony Avritscher3
1Division of Vascular and Interventional Radiology, Joint Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada.
Introduction:
Treatment selection is a challenge for liver-dominant metastatic neuroendocrine tumors (NETs). Post hoc analysis of NETTER-1 suggested that tumor size but not tumor burden predicted progression-free survival (PFS), contrary to prior publications. Analysis of imaging datasets from capecitabine-temozolomide (CapTem), liver-directed therapy (LDT), and peptide receptor radionuclide therapy (PRRT) cohorts was performed to investigate whether imaging features of liver metastatic disease may guide treatment selection.
Methods:
Patients with measurable liver-dominant metastatic NET were identified from imaging datasets from two completed multicenter prospective clinical trials, the capecitabine-temozolomide (CapTem) arm of ECOG-ACRIN 2211 (EA2211) and Randomized Embolization Trial for NeuroEndocrine Tumors (RETNET). A retrospective institutional cohort of consecutive patients treated with PRRT was reviewed for comparison. Extent of liver metastases was categorized by number, maximum diameter, and tumor burden as a fraction of liver volume. These categories were correlated with response category, the primary endpoint, objective response rate (ORR), and PFS by RECIST criteria. Descriptive and graphical analyses were followed by multivariable modeling to test treatment-by-stratum interaction.
Results:
A total of 220 patients were included: CapTem (67), LDT (77), and PRRT (76). Pancreatic (62%, 137/220) and bowel primaries predominated (27%, 59/220). Imaging features were not associated with ORR or PFS in any cohort nor the overall population. The ORR for LDT, PRRT, and CapTem were 65%, 38%, and 25%, respectively (p < 0.001). The respective median PFS were LDT 18.9 months (95% CI: 16.3-24), PRRT 21.6 (95% CI: 14.3-26.9), and 16.6 (95% CI: 11.5-29) for CapTem (p = 0.99).
Conclusion:
In a review of three distinct cohorts of neuroendocrine tumor patients, no imaging features were identified that predicted treatment outcomes or could inform treatment selection. Further comparative analyses are required prior to using these imaging features to guide treatment selection.
