CT evaluation of response in advanced gastroenteropancreatic neuroendocrine tumors treated with long-acting-repeatable octreotide: what is the optimal size variation threshold?

摘要

ObjectiveTo identify a reliable early indicator of deriving progression-free survival (PFS) benefit in patients with advanced gastroenteropancreatic neuroendocrine tumors (GEP-NETs) treated with octreotide long-acting repeatable (LAR).MethodsWe investigated the images of 50 patients with well-differentiated advanced GEP-NETs treated with LAR octreotide and underwent baseline and follow-up thoracic, abdominal, and pelvic computed tomography. Receiver-operating characteristic (ROC) analysis and the Kaplan-Meier method were used to identify the optimal threshold to distinguish between those with and without significant improvement of PFS.ResultsThe optimal threshold for determining a response to octreotide LAR was -10% SLD, with a sensitivity and specificity of 85.7% and 80%, respectively. At this threshold, 19 patients were responders and 31 were non-responders; the median PFS was 20.2 and 7.6 months in responders and non-responders (hazard ratio, 2.66; 95% confidence interval, 1.32-5.36).ConclusionA 10% shrinkage in tumor size is an optimal early predictor of response to octreotide LAR in advanced GEP-NETs.Key points center dot Octreotide LAR can significantly prolong PFS among patients with well-differentiated advanced GEP-NETs.center dot No optimal tumor size-based response criteria are reported in GEP-NETs with octreotide.center dot Ten percent tumor shrinkage is a reliable indicator of the response to octreotide for advanced GEP-NETs.