New Biomarkers for Diagnosis and Prognosis

Pamela Kunz, MD: Biomarkers for NETs [neuroendocrine tumors] are still in development. We don’t have many great biomarkers to date. One that has been around for a long time and is still used is the presence or absence of a somatostatin receptor. This is a unique characteristic for neuroendocrine tumors. It is identified through the use of the gallium-68-DOTATATE PET [positron emission tomography]. That is usually done as a PET/CT [computed tomographpy] but can also be done as a PET/MRI [magnetic resonance imaging]. This has almost completely replaced the use of the older-generation Octreoscan.

The reason the gallium-68-DOTATATE PET is preferred is that the resolution is much better. It shows the extent of disease, so in a sense, that helps us with prognosis. It tends to be positive for patients with grades 1 and 2 NETs and sometimes also the well-differentiated grade 3 neuroendocrine tumors. In addition, it also has implications on treatment selection because we know that patients who are somatostatin receptor avid can potentially be candidates for peptide receptor radionuclide therapy, such as the lutetium 177Lu-DOTATATE.

In addition to somatostatin receptors serving as a biomarker, we’re in search of other biomarkers through imaging, tissue, and genomics. We don’t have additional biomarkers in these realms yet, but there are ongoing investigations. I’ll add that the new WHO [World Health Organization] classification of well-differentiated grade 3 pancreatic neuroendocrine tumors has also opened up this question of how that has implications on both prognosis and treatment. That question is unanswered right now, but that’s a tissue-based biomarker of using both a grade and degree of differentiation that we’ve used for years. This new category has raised this question again of what implications that might have for patients, and that’s still unknown.

Transcript Edited for Clarity