The complexity of the clinical management of neuroendocrine neoplasia (NEN) is
exacerbated by limitations in imaging modalities and a paucity of clinically
useful biomarkers. Limitations in currently available imaging modalities
reflect difficulties in measuring an intrinsically indolent disease,
resolution inadequacies and inter-/intra-facility device variability and that
RECIST (Response Evaluation Criteria in Solid Tumors) criteria are not optimal
for NEN. Limitations of currently used biomarkers are that they are secretory
biomarkers (chromogranin A, serotonin, neuron-specific enolase and
pancreastatin); monoanalyte measurements; and lack sensitivity, specificity
and predictive capacity. None of them meet the NIH metrics for clinical usage.
A multinational, multidisciplinary Delphi consensus meeting of NEN experts (n
= 33) assessed current imaging strategies and biomarkers in NEN management.
Consensus (>75%) was achieved for 78% of the 142 questions. The panel
concluded that morphological imaging has a diagnostic value. However, both
imaging and current single-analyte biomarkers exhibit substantial limitations
in measuring the disease status and predicting the therapeutic efficacy.
RECIST remains suboptimal as a metric. A critical unmet need is the
development of a clinico-biological tool to provide enhanced information
regarding precise disease status and treatment response. The group considered
that circulating RNA was better than current general NEN biomarkers and
preliminary clinical data were considered promising. It was resolved that
circulating multianalyte mRNA (NETest) had clinical utility in both diagnosis
and monitoring disease status and therapeutic efficacy. Overall, it was
concluded that a combination of tumor spatial and functional imaging with
circulating transcripts (mRNA) would represent the future strategy for real-
time monitoring of disease progress and therapeutic efficacy
