Defining disease status in gastroenteropancreatic neuroendocrine tumors: Choi-criteria or RECIST?

Purpose: Adequate monitoring of changes in tumor load is fundamental for the assessment of the course of disease and response to treatment. There is an ongoing debate on the utility of RECIST v1.1 in gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Methods: In this retrospective real-life cohort study, Choi-criteria were compared with RECIST v1.1. The agreement between both criteria and the association with survival endpoints were evaluated. Results: Seventy-five patients were included with a median follow-up of 35 months (range 8–53). Median progression-free survival (mPFS) according to RECIST v1.1 was 15 months (range 2–50) compared to 14 months (range 2–50) in Choi. According to RECIST, 33 (44%) patients were classified as having stable disease (SD), 40 (53%) as progressive disease (PD) and two (3%) patients as partial response (PR), compared to 9 (12%) patients classified as SD, 50 (67%) as PD and 16 (21%) as PR according to Choi-criteria. Overall concordance between the criteria was moderate (Cohen’s Kappa = 0.408, p < 0.001) and agreement varied between 57 and 69% at each consecutive scan (p < 0.001). Survival analysis showed significant differences in overall survival (OS) for RECIST v1.1 categories PD and non-PD (log-rank p = 0.02), however, in Choi no significant differences in OS were found (p = 0.27). Conclusion: RECIST v1.1 had a better clinical utility and prognostic value compared to Choi-criteria. Still, RECIST were also not sufficient to adequately predict OS. This outlines the need for new tools that provides accurate information on the disease course and treatment response to support precise prognostication in patients with GEP-NETs. Graphical abstract: [Figure not available: see fulltext.]