Dr Thorvardur Halfdanarson Discusses Lack of Risk Factors, Biomarkers in NETs

There is a lot of disagreement, even within the neuroendocrine tumor (NET) circles, that there are biomarkers that predict outcomes and some that may even predict responses to therapy, explained Thorvardur Halfdanarson, MD, associate professor of medicine and consultant in medical oncology, Mayo Clinic.

Transcript

Are there any identified risk factors for developing neuroendocrine tumors?

Interesting question. So, we have studied that in pancreatic neuroendocrine tumors. We used a large dataset at the Mayo Clinic to look at that. We were not able to find anything that predicted NETs. For small bowel NETs, we know from large population studies in Sweden there may be a low famial risk. So, I would say all patients who have a first degree relative—a parent, or a child, or a sibling—with NETs should seek out one of these medical centers that are actually studying familial NETs, including the NIH [National Institutes of Health] and the University of Iowa.

As for other risk factors, we don’t know. They are becoming more common, partly because we’re better at diagnosing them, but also I think because they are becoming more common. We have essentially failed to identify risk factors.

Are there any identified biomarkers that guide treatment protocol?

It’s a hot topic. I would say for most NET patients, biomarkers add little. There is a lot of disagreement, even within the NET circles, that there are biomarkers that predict outcomes and some that may even predict responses to therapy, and there are some that may have diagnostic value. The most commonly used one is chromogranin. It has such severe limitations for most parts that we can’t rely on it for diagnosis and we can’t really rely on it for treatment decisions.

There are other markers, including the marker called pancreostatin, which was discussed at a couple of posters here, that may have some better, more reliable characteristics than chromogranin A. And then there are some novel genomic markers that have been studied and look promising. But, essentially, larger studies are needed. What we need to know is really, we need to do studies that confirm or refute that these markers actually change treatment decisions and eventually change outcomes. If the marker is not going to change the outcomes, I don’t think we should do it.