Usefulness of Semiautomated 3D Volumetric Assessment of Liver Tumor Burden for Patients With Unresectable Pancreatic Neuroendocrine Tumor: A Pilot Study

Objectives In patients with metastatic pancreatic neuroendocrine tumors (PanNETs), the Ki-67 index is objectively assessed by pathologists; however, liver tumor burden (LTB) depends on the subjective judgment of physicians. This study aimed to elucidate the usefulness of the semi-automated 3D volumetric assessment of LTB in patients with PanNET. Materials and Methods We retrospectively reviewed 29 patients (40 computed tomographies [CTs]) with metastatic PanNETs. LTB was measured using a semiautomated 3D volumetric software program (volumetric assessment) or evaluated independently by 6 clinicians using CT imaging (visual assessment). The treatment map was classified into 3 groups based on LTB and Ki-67 index. Results Visual and volumetric assessments of the LTB were well correlated. The LTB was significantly higher on visual assessment than volumetric assessment (P < 0.01). Categorization on the map was consistent between the visual and volumetric evaluations in 23 patients (equal group). The remaining 6 patients were overestimated by visual assessment (overestimated group). Progression-free survival was significantly longer in patients in the 'equal group' than the 'overestimated group' (981 vs 366 days, P < 0.01). Conclusions This pilot study revealed a good correlation between visual and volumetric assessments, and visual assessment overestimated LTB, compared to volumetric assessment.