Optimisation of the Size Variation Threshold for CT Evaluation of Response in Advanced Gastroenteropancreatic Neuroendocrine Tumors Treated with Octreotide LAR

#1721

Introduction: In advanced gastroenteropancreatic neuroendocrine tumors (GEP-NETs), somatostatin analogs treatment rarely achieve a reduction of -30% in the sum of longest diameters (SLD) of target lesions required by Response Evaluation Criteria in Solid Tumors (RECIST) for an ‘objective response’. The implication of Stable Disease (SD) as an additional indicator of therapeutic effect is often uncertain.

Aim(s): We sought to determine a threshold as the reliable early indicator which may derive PFS benefit from this therapy.

Materials and methods: Thirty-three patients with well differentiated advanced GEP-NETs (WDGEP-NETs) treated with octreotide LAR underwent thoracic, abdominal and pelvic computed tomography at baseline and at first follow-up after therapy were enrolled. Thresholds from -30% to +20% was defined by the best change in the sum of the longest diameters (ΔSLD) of target lesions, Kaplan–Meier and receiver operating characteristic (ROC) analysis were used to determine the optimal size threshold to distinguish ‘responders’ from ‘non-responders’ with respect to significant improvement in PFS.

Conference: 14th Annual ENETSConcerence (2017)

Presenting Author: Luo Y

Authors: Luo Y, Chen J,

Keywords: GEP-NETs, Octreotide LAR, Progression-free Survival,