Blood measurement of neuroendocrine gene transcripts defines the effectiveness of operative resection and ablation strategies

Background Surgery is the only curative treatment for gastroenteropancreatic neuroendocrine tumors (GEP-NETs), but the prediction of residual disease/recurrence is limited in the absence of optimal biomarkers. We examined whether a blood-based multianalyte neuroendocrine gene transcript assay (NETest) would define tumor cytoreduction and therapeutic efficacy. Methods The NETest is a polymerase chain reaction-based analysis of 51 genes. Disease activity is scaled 0-100%; minimal 47%. A total of 35 GEP-NETs in 2 groups were evaluated. I: after surgery (R0, n = 15; residual, n = 12); II: nonsurgery (n = 8: embolization with gel-foam alone [bland: n = 3]), transarterial chemoembolization (n = 2), and radiofrequency embolization (n = 3). Measurement (quantitative real-time-polymerase chain reaction) and chromogranin A (CgA; enzyme-linked immunosorbent assay) were undertaken preoperatively and 1 month after treatment. Results NETest score was increased in 35 (100%) preoperatively; 14 (40%) had increased CgA (χ² = 30, P <2 × 10^-8). Resection reduced NETest from 80 ± 5% to 29% ± 5, (P 2 = 0.29, P =.03). Cytoreduction significantly reduced NETest from 82 ± 3% to 41% ± 6, P