Response Criteria and PRRT Treatment

Through her 2021 NETRF Investigator Award, Lisa Bodei, MD, PhD, professor of radiology at Weill Cornell Medical College, attending physician and director of targeted radionuclide therapy, molecular imaging and therapy service at Memorial Sloan Kettering Cancer Center, is defining how to use PET scans to evaluate a patient’s response to treatment such as peptide receptor radionuclide therapy (PRRT). PET is an incredibly accurate technology to stage neuroendocrine tumors and select patients for PRRT, but it’s not yet clear how to use PET to monitor treatment response.

To establish clear PET criteria that can be used worldwide by clinicians and researchers, Dr. Bodei and her team, in collaboration with Dr. Wolfgang Weber, director of the nuclear medicine department at the Technical University of Munich, Germany, are analyzing imaging data from a 90-patient cohort from the US and Germany to compare different approaches to quantify tumor response to therapy. Possible approaches via PET include assessing tumor radioactive uptake and/or measuring tumor volumes.

The response criteria under development are termed “PRESCIENT” (Pet REsponSe CrItEria for Neuroendocrine Tumors), and so far, Dr. Bodei and her team have found that the best way to identify PRRT responders vs. non-responders is to monitor tumor volume and check for the appearance of new lesions. They found that after PRRT, responding tumors are more prone to decrease in volume than in radioactive uptake (so called SUVmax). These preliminary results were just featured as a “top rated oral presentation” at the annual meeting of the European Association of Nuclear Medicine (EANM), the largest nuclear medicine conference world-wide.

Dr. Bodei and her team will next test these criteria prospectively in a small group of patients to ensure that these criteria hold when evaluating new patients undergoing PRRT. Dr. Bodei and Dr. Weber believe that the evidence-based PRESCIENT criteria will address an unmet need in NET management by helping clinicians make the right treatment decisions for patients and allow the inclusion of PET in clinical trials to better assess the effectiveness of new drugs.