Staging and Management Updates for Neuroendocrine Tumors (NET)

Slide of a neuroendocrine tumor
Article Summary
  • An updated set of guidelines describes the state of the clinical field of neuroendocrine tumors.
  • Neuroendocrine tumors form from specialized cells that receive and send messages from and to neurons and release hormones.
  • Dr. Aman Chahaun notes the growing role for endoscopic management of many of these tumors, decreasing the need for surgery.

A newly released, updated set of guidelines gives a snapshot of the state of the clinical field of neuroendocrine tumors, a rare kind of cancer that arises from neuroendocrine cells in a variety of organs.

The updated staging guidelines for the American Joint Committee on Cancer are summarized in a manuscript published April 29 in CA: A Cancer Journal for Clinicians. The guidelines highlight several recent changes and recommendations for neuroendocrine tumors in the digestive system or the pancreas.

“There’s a lot that goes into cancer staging,” said Aman Chauhan, M.D., who leads the newly established Neuroendocrine Tumor Program at Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine, and who is first author on the staging publication. “Survival and outcomes and key changes in how we diagnose these tumors – all that feeds into staging.”

Neuroendocrine tumors form from specialized cells throughout the body that receive and send messages from and to neurons and release hormones in response. In some cases, the cancers are first spotted due to the tumors’ overproduction of a given hormone and the unusual symptoms that result. For example, overproduction of serotonin leads to a condition known as carcinoid syndrome, which can cause skin flushing, gastrointestinal upset and wheezing.

Dr. Aman Chauhan
Dr. Aman Chauhan leads Sylvester’s Neuroendocrine Tumor Program.

Although neuroendocrine tumors are relatively rare, their incidence is rising, from one in 100,000 in the U.S. in the 1970s to around eight in 100,000 today. That rapid increase might be due to improved diagnostics in the past few decades, Dr. Chauhan said, although it’s not clear whether the cancer itself is also becoming more common.

For example, researchers have recently come to appreciate that a common class of medications for chronic reflux or heartburn, proton-pump inhibitors, is linked to increased rates of gastric neuroendocrine tumors, which are now among the most prevalent gastrointestinal neoplasms.

Dr. Chauhan called out several key points in the guidelines that are new since the previous, 2018 version:

  • A growing role for endoscopic management of many of these tumors, decreasing the need for surgery. Many neuroendocrine tumors of the gastrointestinal system are picked up during endoscopies or colonoscopies. They can often be removed during the course of the scoping procedures, if they are small enough.
  • A recommendation to move away from using levels of chromogranin A (CgA) in the blood to screen for neuroendocrine cancer. These blood tests have not been shown to have much utility for diagnosis.
  • Advocating for increased use of a newer PET scan, DOTATATE imaging, to stage for these cancers. This form of molecular imaging uses radio-labeled peptides that bind to a protein often found on the surface of neuroendocrine cancer cells (a somatostatin receptor). This imaging technique lights up all tumors in the body that bear this marker and can pinpoint small amounts of cancer often missed by other methods.
  • A highlight on current outcomes data for neuroendocrine tumors. This data can be taken from the National Cancer Database, or NCDB, a nationwide clinical oncology database from the American College of Surgeons.

The guidelines also call out future directions for the field Dr. Chauhan is helping drive through his leadership of Sylvester’s Neuroendocrine Tumor Program. It’s one of the few U.S. programs for neuroendocrine cancers that treats and studies all types of these tumors and merges care and research from multiple disciplines.

Although these cancers are rare, the new Sylvester clinic is already busy with patients, Dr. Chauhan said, pointing to an unmet need in South Florida and the surrounding region for expertise in these tumors.

Dr. Chauhan is particularly excited about an emerging area of neuroendocrine cancer treatment related to the molecular imaging techniques called out in the updated guidelines. This method, known as theranostics, brings the cancer-killing power of radiation to bear on tumor cells in a targeted manner.

The radio-labeled peptides are first used with a low level of radiation to ensure that the drug’s target is present on that patient’s cancer. Then, a similar molecule bearing a high level of radiation is given as a therapy, bringing radiation directly to the diseased cells. This method avoids much of the collateral damage of traditional radiation, which irradiates both cancer cells and surrounding healthy cells.

“Many cancer treatments, including most chemotherapies, are really a shot in the dark,” Dr. Chauhan said. “We don’t know if they will help a patient before the patient starts on the treatment. That’s the beauty of this approach. It merges precision diagnosis and therapy together.”

Tags: Dr. Aman Chauhan, neuroendocrine cancer, Neuroendocrine Tumor Program, Sylvester Comprehensive Cancer Center