Screening for brain metastases in patients with stage III non-small-cell lung cancer, magnetic resonance imaging or computed tomography? A prospective study

Non-small-cell lung cancer (NSCLC) guidelines advise to screen stage III NSCLC patients for brain metastases (BMs), preferably by magnetic resonance imaging (MRI) or when contraindicated or not accessible a dedicated contrast enhanced-computed tomography (dCE-CT), which can be incorporated in the staging ¹⁸Fluodeoxoglucose-positron emission tomography (¹⁸FDG-PET-CE-CT). In daily practice, often a dCE-CT is performed instead of a MRI. The aim of the current study is to evaluate the additive value of MRI after dCE-CT, incorporated in the ¹⁸FDG-PET-CE-CT.

It is an observational prospective multicentre study (NTR3628). Inclusion criteria included stage III NSCLC patients with a dCE-CT of the brain incorporated in the ¹⁸FDG-PET and an additional MRI of the brain. Primary end-point is percentage of patients with BM on MRI without suspect lesions on dCE-CT. Secondary end-points are percentage of patients with BM on dCE-CT and percentage of patients with BM ≤ 1 year of a negative staging MRI.

Sixteen (7%) patients with extracranial stage III had BM on dCE-CT and were excluded. One hundred forty-nine patients were enrolled. 7/149 (4.7%) had BM on MRI without suspect lesions on dCE-CT. One hundred eighteen patients had a follow-up of at least 1 year (four with BM on baseline MRI); eight of the remaining 114 (7%) patients developed BM ≤ 1 year after a negative staging brain MRI.

Although in 7% of otherwise stage III NSCLC patients, BMs were detected on staging dCE-CT, MRI brain detected BMs in an additional 4.7%, which we consider clinically relevant. Within 1 year after a negative staging MRI, 7% developed BM.