Marker (+) CNS germ cell tumors in remission: are surveillance MRI scans necessary?

BACKGROUND: Patients with marker (+) CNS germ cell tumors are usually followed with both surveillance MRI scans and serum tumor markers. We hypothesized that patients with elevated serum tumor markers at diagnosis who achieve a complete biochemical and radiological remission may not need surveillance MRI scans. PROCEDURE: We retrospectively identified 31 patients with CNS germ cell tumors who presented with an elevated serum tumor marker at the time of diagnosis. We reviewed the records of those patients who (1) achieved a complete biochemical and radiological remission and (2) later suffered tumor recurrence to determine whether the recurrence was detectable biochemically, radiologically, or via both modalities.
RESULTS: Nine patients suffered tumor recurrence following initial remission. All 9 had elevated serum tumor markers at recurrence and 8 had MRI evidence of recurrence. The 1 patient with isolated biochemical evidence of recurrence developed MRI evidence of recurrence 15 months later without intervening treatment. One other patient (not one of the 9) had a secondary malignancy (anaplastic astrocytoma) identified by brain MRI scan.
CONCLUSIONS: Patients with CNS germ cell tumors who present with elevated serum tumor markers at diagnosis and achieve a complete biochemical and radiological remission may not need surveillance MRI scans to monitor for recurrence, but MRI scans may be considered to monitor for secondary malignancy. If other series replicate these findings, surveillance via monitoring of serum tumor markers only could be done and omission or reduction of the frequency of surveillance MRI scans could save a significant amount of money.