Diffusion tensor imaging (DTI) may indicate prognosis among patients with brain metastases and the likelihood of their response to immunotherapy, according to a study published in Cancer Research.
Researchers from the United Kingdom sought to identify which patients with brain metastases would respond better to treatment. Twenty-six patients participated in the study. The researchers matched preoperative DTI with image-guided sampling of the brain-tumor interface in the 26 patients during resection of a brain metastasis and assessed mean diffusivity (MD) and fractional anisotropy (FA). They analyzed the tissue samples for vascularity, inflammatory cell infiltration, growth pattern, and tumor expression of proteins associated with growth or local invasion such as Ki67, S100A4, and MMP2, 9, and 13.
The results showed that a lower FA in the peritumoral region indicated more white matter tract disruption and this independently predicted longer overall survival times. “Of all the biological markers studied, only increased density of CD3+ lymphocytes in the same region correlated with decreased FA as well as confounding completely the effect of FA in multivariate survival analyses,” the authors wrote.
"This result suggests that the immune system is holding in check some metastatic cancers and that monitoring just one metastasis in the brain is a reflection of the body's overall control of the disease," lead author Philip Rudland, PhD, a professor of biochemistry at the University of Liverpool, said in a release.
Co-author Rasheed Zakaria, PhD, MA, Neurosurgical Registrar and Research Fellow also at the University of Liverpool, added: "There is huge excitement about immune therapy in brain tumours but without the time and risk of a neurosurgical operation it is impossible to know which patients should have treatment. Since most patients with a brain tumour undergo MRI scanning we asked the simple question, are there any changes on the MRI scans that correlate with the brain's immunological reaction to the cancer?"
The researchers plan to continue studies in a larger group of patients.