PET-CT vs brain MRI for the detection of cerebral metastases of melanoma, a 5-year retrospective study.

BACKGROUND: Melanoma patients present a high risk of developing extra cutaneous metastases. PET-CT is one of the preferred examinations for the staging of oncological patients. It is not the method of choice to detect brain metastases, but this technique has shown significant improvement and allows the detection of some of them, although it is unclear how it performs compared to the MRI, the current gold standard for diagnosing brain metastases.

OBJECTIVE: To compare the accuracy of PET-CT and cerebral MRI to detect brain metastases in melanoma patients.

METHODS: We retrospectively included all patients diagnosed with melanoma stage IIC-IV (AJCC 8th Edition-2017) presented at the skin tumor board of the University Hospital of Bern between 01/2018 and 12/2022. All radiological reports extracted from the patient management system were analyzed to assess a discrepancy between the visibility of brain metastases on PET-CT and brain MRI.

RESULTS: In this study including 393 patients, brain MRI demonstrated significantly higher performance than PET-CT in detecting brain metastases. Cerebral metastases were detected completely, partially or were not detected by PET-CT in respectively 2 patients (4%), 15 patients (32%) and 30 patients (64%) out of 47.

CONCLUSION: Despite the increasing performance of PET-CT, this study highlights the crucial role of brain MRI, which remains the gold standard to detect cerebral metastases. Brain MRI should be performed on patients with high-risk melanoma from stage IIC to exclude brain metastases.