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Page 6 of 16 Enrique et al. J Cancer Metastasis Treat 2019;5:54 I http://dx.doi.org/10.20517/2394-4722.2019.20

Spectroscopy may increase the accuracy of MRI in differentiating tumors from necrosis in patients with
metastases who have been irradiated, using choline/NAA and choline/creatine ratios . According to a
[26]
meta-analysis of 261 patients, it can also guide a clinician’s therapeutic approach by adding information that
could contribute to a differential diagnosis of primary malignant tumors such as high-grade gliomas; the
study concluded that the most useful spectroscopy parameter is the choline-NAA ratio, preferably using a
multi-voxel technique in the peritumoral region . However, in contrast, a meta-analysis of advanced MRI
[27]
metrics that included 24 spectroscopy studies found no reliability of this technology in distinguishing high-
grade gliomas from metastases using the choline-creatine ratio; the authors had excluded cases in which the
choline-NAA ratio was used due to insufficient data .
[28]

Hence, there is a lack of robust data supporting the routine use of MRI spectroscopy for differentiating
metastases from high-grade gliomas, but it remains an important tool supporting the differential diagnosis
of brain metastases from benign and low-grade gliomas and necrosis in irradiated patients .
[29]

TREATMENT
The therapeutic approach to patients with brain metastasis is intended to relieve symptoms, such as
headache, vomiting, and neurological focalization; the success of this largely depends on the presence of
cerebral hypertension syndrome secondary to perilesional cerebral edema. Surgical management continues
to be the standard of treatment, accompanied by radiotherapy using two different techniques: stereotactic
radiosurgery (SRS) or whole-brain radiation therapy (WBRT) (or a combination of these) .
[30]
Management of brain edema
The treatment of cerebral edema with systemic steroids such as dexamethasone has been practiced for more
than five decades . Its efficacy is well known in terms of the clinical improvement of symptoms associated
[31]
with vasogenic edema through its reduction of capillary permeability and regulation of the elevation of tight
endothelial junctions involved in the physiology of the blood–brain barrier by binding to glucocorticoid
receptors [32-34] .

In actuality, the pharmacological measures previously adopted for the management of edema, including
osmotic diuretics such as mannitol and glycerol and loop diuretics such as furosemide, are no longer
considered standard for the treatment of cerebral edema secondary to metastasis. Because osmotic diuretics
cause a redistribution of fluid from the intracellular space to the extracellular space, they reach a plateau
within a few hours, reducing their effectiveness .
[35]
Even though there is not a defined dexamethasone scheme, the most utilized dose in patients with clinical
cerebral edema is 4 to 8 mg/day .
[33]
According to a recent joint update of the American Society of Clinical Oncology and the Society for Neuro-
Oncology, they endorse a practice guideline regarding the role of steroids in brain tumors. The recommended
dose depends on symptom severity with an initial dose of 8 mg in mildly symptomatic patients and 16 mg
in severely symptomatic patients .
[36]

Management of seizures
In patients who have not presented with seizures, the use of an antiepileptic agent in a prophylactic manner
is currently not recommended, following a systematic review by Perry et al . In that study, no significant
[37]
differences were found in reduction of risk of convulsive episodes in patients who were recently diagnosed
with brain metastases and had never presented with seizures, between administration of the drug and only
observation.