https://orcid.org/0000-0002-9873-7507
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ABSTRACT
Objectives
Neuroendocrine tumors (NETs) are a heterogeneous group of cancers arising from neuroendocrine cells. The aim was to evaluate objective response rate (ORR) as a predictor of overall survival (OS) in patients with metastatic NETs (mNETs) treated with radioembolization (RE).
Methods
Randomized controlled trials and observational studies of RE treatment of mNETs were identified by systematic literature review (SLR). Pooled ORR and OS estimates were calculated and a weighted generalized linear model (GLM) of ORR as a predictor of OS was derived, stratified by ORR assessment criteria and RE type (Yttrium-90 resin or glass microspheres).
Results
The SLR identified 32 observational studies. Mean ORR was 41% (95% confidence interval 38–45%). The Yttrium-90 resin and glass microsphere GLMs accounted for 59% and 57% of OS deviance, respectively. ORR was a significant predictor of OS in the resin microspheres model (p < 0.001), but not the glass microspheres model (p = 0.11).
Conclusions
A weighted GLM showed a significant relationship between ORR and OS in patients with mNETs treated with Yttrium-90 resin microspheres. ORR could therefore potentially be an OS surrogate in future trials of Yttrium-90 resin microspheres. Further research is needed to confirm the relationship between ORR and OS and the difference between resin and glass microspheres.
Declaration of interest
R F Pollock is the sole Director of Covalence Research Ltd, which received consultancy fees from Sirtex Medical United Kingdom Ltd to conduct the systematic literature review, run the analyses, and prepare the manuscript. V K Brennan is a full-time employee of Sirtex Medical United Kingdom Ltd, a subsidiary of Sirtex Medical Pty. Ltd, the manufacturer of SIR-Spheres® Y-90 resin microspheres. R Peters is a full-time employee of Sirtex Medical Europe GmbH, a subsidiary of Sirtex Medical Pty. Ltd, the manufacturer of SIR-Spheres® Y-90 resin. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
Reviewer disclosures
Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.
Author contributions
RFP and VKB conceived of the analysis. RFP conducted the statistical analysis. RFP, VKB, RP, and PMP interpreted the data. RFP drafted the manuscript, and VKB, RP, and PMP subsequently revised the manuscript critically for intellectual content. All authors approve of the final version to be published and agree to be accountable for all aspects of the work.