Early and precise delineation of therapeutic responses are key issues in NEN/tumor management. Imaging is currently used but exhibits limitations in sensitivity and specificity. NETest values (80 –100%) were more accurate and occurred at a significantly earlier
time point than CgA and predicted SSA treatment response.

We evalutated the NETest prior to PRRT, during therapy and at 3 and 6 months after therapy in 54 177Lu-treated GEP-NET. The NETest accurately correlated with standard morphologic and functional imaging and therefore with treatment response and outcome of therapy.

Time prior to disease progression identified by imaging. A rise in NETest >70% occurred a median 1.62 years before imaging confirmation of tumor progression (failure of therapy). A rise in NETest >80% occurred a median 0.76 years before imaging confirmation of tumor progression (failure of therapy).

Relationship between NETest score and clinical management; Blood NETest is an accurate diagnostic and can
be of use in monitoring disease status and facilitating management change in both watch-and-wait and treatment
cohorts.