FDG PET/CT imaging can monitor effectiveness of immunotherapy in melanoma patients

18F-FDG PET/CT imaging can help providers monitor the effectiveness of immunotherapy with ipilimumab in metastatic melanoma patients, according to new findings published in the Journal of the Nuclear Medicine.

“Checkpoint inhibitor therapy is now a standard therapy for metastatic melanoma,” co-author Wolfgang A. Weber, MD, of the Technical University of Munich in Munich, Germany, and formerly of New York City’s Memorial Sloan Kettering Cancer Center, said in a prepared statement. “However, there were concerns about whether FDG PET/CT could be used to monitor tumor response to this immunotherapy, because inflammatory reactions to the immunotherapy may cause false positive findings. The present study shows that tumor response to checkpoint inhibitor therapy with ipilimumab can be assessed accurately by FDG PET after completion of ipilimumab therapy.”

Compared to chemotherapy, ipilimumab therapy has been found to improve the survival of 15-20 percent of metastatic melanoma patients. Assessing when a patient is responding to ipilimumab, however, can be a challenge.

Weber and colleagues studied 60 metastatic melanoma patients before and after treatment, using FDG PET/CT scans to measure their response. The team found that assessing tumor response using Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST) was associated with the patient’s overall survival.

“FDG PET/CT is routinely used to stage melanoma,” Weber said in the same statement. “The present study suggests that it also can be used to monitor tumor response to ipilimumab therapy and predict outcome.”