False-Negative MRI Findings for Leptomeningeal Metastases with Use of Bevacizumab.

Abstract

The phenomenon of mutation-associated site-specific metastasis, such as the metastases of erb-b2 receptor tyrosine kinase 2 gene (HER2)-amplified breast and gastroesophageal cancers to involve the brain has been reported earlier.1Feilchenfeldt J. Vargas Z. Siano M. et al.Brain metastases in gastro-oesophageal adenocarcinoma: insights into the role of human epidermal growth factor receptor 2 (HER2).Br J Cancer. 2015; 113: 716-721Crossref PubMed Scopus (15) Google Scholar The article by Li et al.2Li Y.-S. Jiang B.-Y. Yang J.-J. et al.Leptomeningeal metastases in patients with NSCLC with EGFR mutations.J Thorac Oncol. 2016; 11: 1962-1969Abstract Full Text Full Text PDF PubMed Scopus (160) Google Scholar on the tendency of EGFR-mutant adenocarcinomas to seed the leptomeninges adds to the literature on this interesting phenomenon. Li et al. do provide an extensive discussion on the etiopathology, but this pertains to metastases to brain parenchyma and does not explain the tendency toward leptomeningeal metastasis (LM), a less common phenomenon. It would also have been interesting to know whether the metastatic cells seeding the leptomeninges also carried the same mutation. The apparent lower incidence of LM in the adenocarcinoma with wild-type EGFR could have another explanation. The basis of diagnosis of 76 cases of LM in mutant cases was “by magnetic resonance imaging only,” whereas 34 cases were diagnosed by magnetic resonance imaging in the wild-type cancers (see Table 1 in Li et al.2Li Y.-S. Jiang B.-Y. Yang J.-J. et al.Leptomeningeal metastases in patients with NSCLC with EGFR mutations.J Thorac Oncol. 2016; 11: 1962-1969Abstract Full Text Full Text PDF PubMed Scopus (160) Google Scholar). Adenocarcinomas with wild-type EGFR are more likely to be treated with bevacizumab, an antiangiogenic agent. It has been reported that bevacizumab could lead to false-negative results of imaging of LM3Kleinschmidt-DeMasters B.K. Damek D.M. The imaging and neuropathological effects of bevacizumab (Avastin) in patients with leptomeningeal carcinomatosis.J Neurooncol. 2010; 96: 375-384Crossref PubMed Scopus (25) Google Scholar and a lower detection rate. It is possible that the lower rate of LM in wild-type tumors is a reflection of higher use of bevacizumab in this group. Perhaps the authors could reanalyze the data to take into account bevacizumab-treated patients to confirm their findings. Leptomeningeal Metastases in Patients with NSCLC with EGFR MutationsJournal of Thoracic OncologyVol. 11Issue 11PreviewLeptomeningeal metastases (LM) have increased in patients with NSCLC, and prognostic factors and outcomes for LM with EGFR gene mutations have not been well studied. Full-Text PDF Open ArchiveLittle Influence of Bevacizumab in Diagnosis of Leptomeningeal Metastases in Current StudyJournal of Thoracic OncologyVol. 12Issue 1PreviewIt is very interesting to find out about the phenomenon that bevacizumab might lead to false-negative imaging of leptomeningeal metastases (LM).1 However, the conclusion was drawn from only two patients,2 and the influence of bevacizumab in diagnosis of LM needed further exploration. Brain magnetic resonance imaging (MRI) plays an important role in diagnosis of LM, but with low sensitivity and specificity. In the current study,3 we would have performed lumbar puncture for those patients complaining of neurological symptoms, and there were a total of eight patients in whom carcinoma cells were found in the cerebrospinal fluid, but with no positive presentation on brain MRI, and all eight patients had not received bevacizumab therapy before LM, indicating that the false-negative results of imaging of LM may be related more to the complex complication and the inferiority of brain MRI in identifying LM in their early stage. Full-Text PDF Open Archive