PET/CT May Yield False Positive Findings in Early Stage Melanoma Interview with:
Benjamin Y. Scheier, MD
Division of Hematology/Oncology
Department of Internal Medicine
University of Michigan, Ann Arbor

Medical Research: What is the background for this study? What are the main findings?

Dr. Scheier: Existing data suggests that PET/CT has use in the detection of metastases from multiple primary tumor types. However, PET/CT lacks data supporting its use in staging asymptomatic patients with early-stage melanoma, may inconsistently impact treatment decisions, and carries a false-positive finding risk that may detract from its use. To evaluate an evolving practice, this study aims to assess the use of PET/CT in detecting occult metastases in SLN-positive melanoma prior to resection. In this retrospective evaluation of patients with melanoma and clinically silent regional lymph nodes treated at the University of Michigan, only 7% had PET/CT findings that ultimately identified metastatic melanoma and precluded LND. Of the 46 patients who underwent a preoperative PET/CT, 15 (33%) had intense uptake distant from the primary tumor and local lymph node basin. Nine of those 15 patients (60%) had abnormalities biopsied prior to LND. Three of the 9 biopsies yielded metastatic melanoma, a false-positive rate of 67% for PET/CT in identifying distant metastases in asymptomatic patients.

Medical Research: What should clinicians and patients take away from your report?

Dr. Scheier: In our retrospective review, we found that PET/CT has a high false-positive rate and a minimal effect on patient management in this setting, and is best reserved in its established role evaluating treatment response and recurrence. These data also suggest that a significant majority of asymptomatic patients with newly discovered microscopic SLN-positive melanoma do not have synchronous metastases detectable by PET/CT. Our review also identified the potential for treatment delays, increased exposure to risk from additional procedures, and increased health care resource usage that patients incur following detection of asymptomatic abnormalities by preoperative PET/CT.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Scheier: We recommend that PET/CT staging be reevaluated as a category 2B recommendation by the NCCN and its use further evaluated prospectively in a clinical trial.


Scheier BY, Lao CD, Kidwell KM, Redman BG. Use of Preoperative PET/CT Staging in Sentinel Lymph Node–Positive Melanoma.JAMA Oncol. Published online September 24, 2015. doi:10.1001/jamaoncol.2015.3664.

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Benjamin Y. Scheier, MD (2015). PET/CT May Yield False Positive Findings in Early Stage Melanoma 

Last Updated on September 25, 2015 by Marie Benz MD FAAD