Because neuroendocrine tumors (NETs) tumors can be very small and may develop anywhere in the body, such as the stomach, intestines, pancreas and lungs, finding them at early stages is difficult.
Typical positron emission tomography (PET) scans are not effective in detecting carcinoid tumors, because unlike other cancers, NETs do not consume glucose rapidly. (PET scans normally detect cancer by infusing patients with a glucose preparation and then identifying the body areas where glucose is being consumed or metabolized rapidly.)
A new agent, gallium-68 dotatate (Netspot®), recently FDA-approved and available at Roswell Park, can be used as a PET tracer instead of radiolabeled glucose to identify carcinoid tumors even very small lesions significantly better than any currently available imaging.
How does it work?
While NETs don’t consume glucose like other cancers, their cells do have plenty of receptors for the hormone somatostatin, which regulates the endocrine system. Ga-68 dotatate is a radioactive lookalike of the hormone that binds to the somatostatin receptors, highlighting the tumor on PET imaging.
How is it better than current testing methods?
This imaging approach significantly improves detection of NETs in three important ways:
- Faster process. Completed in a couple hours, this test is much quicker than the onerous three-day octreoscan (which uses a radioactive drug and a gamma camera to measure the radio material over time.
- Better images. Because PET can be used, the physician gets a very clear, high-resolution image that can identify very small lesions that would otherwise be missed.
- Determines treatment. The improved image can help the oncologist choose optimal therapy, such as choosing surgery or systemic therapy. In addition, finding NETs in this manner means the patient would likely be eligible for a new treatment, called Peptide Receptor Radionuclide Therapy (PRRT), that uses hormone-tagged radiation to find and attack the cancer cells.
Who should have this scan?
Physicians plan to use Netspot PET in order to diagnose neuroendocrine tumors, determine treatment options, plan surgery, and monitor for recurrence.
Are there any concerns about this test?
Patients who take long-acting somatostatin analogues (Sandostatin) should delay this test for 3-4 weeks after their last dose.