The effect of FDG-PET imaging on patients with melanoma treated with immunotherapy.

The study looked at the use of FDG-PET imaging to assess long-term outcomes of treatment in patients with melanoma. Researchers found that FDG-PET imaging may be useful in predicting long-term outcomes of treatment in these patients.

Treatment for melanoma has vastly improved in recent years. Immunotherapies have improved the outcomes for patients with advanced melanoma. Immunotherapy boosts the immune system to attack cancer cells. However, long-term outcomes can be difficult to predict. 

CT imaging can be used during and after treatment to see how much cancer is remaining. FDG-PET is another imaging technique that uses a small amount of a radioactive drug to show the difference between healthy and diseased tissues. It is important to research if FDG-PET scanning is a more effective way to predict long-term outcomes of treatment in patients with melanoma.

104 patients with melanoma treated with immunotherapy were included in this study. Patients were followed up for an average of 30.1 months. Response to treatment was evaluated with both CT and FDG-PET imaging.

At 1 year, CT evaluation showed a complete response (CR – no sign of cancer after treatment) in 28% of patients. 66% had a partial response (PR; a decrease in the size of the tumor) and 6% had stable disease (SD – no cancer spread) on CT. On FDG-PET, 75% of patients had a CR, 16% had PR and 9% had SD.

68% of patients with a PR on CT had a CR on FDG-PET. There was no difference in the 1-year progression-free survival (PFS; time from treatment to disease progression) between patients with a CR and a PR or SD on CT imaging. The 1-year PFS based on FDG-PET was 100% in patients with a CR and 57% in patients with a PR or SD. 

The study concluded that FDG-PET may be a useful tool to monitor long-term outcomes of treatment in patients with melanoma.

The study population was quite small. Larger studies are needed to confirm results.