A new study suggests that the location of brain metastasis is not random; cancer cells may have the ability to adapt to regional microenvironments in the brain that allow the cancer to progress.
“We discovered that different types of cancer are more likely to show up in specific parts of the brain once they metastasize, indicating the location of tumors follow a distinct pattern,” said Gabriel Zada, MD, Brain and Tumor Neurosurgeon with Keck Medicine of University of Southern California (USC) and senior author of the study.
Zada and colleagues analyzed the location of brain tumors caused by five common types of cancer: melanoma (a type of skin cancer), lung, breast, renal (kidney) and colorectal. They discovered that lung cancer and melanoma showed a higher likelihood for the metastasis to be at the frontal and temporal lobes (which sit behind the ears). Breast, renal and colon cancers had a higher propensity to spread to the back of the brain, such as the cerebellum and brainstem.
The findings are important not only because they may predict where a specific cancer may spread in the brain, but because they also have implications for how brain tumors grow.
To reach their conclusions, the researchers collected data from patients with metastatic brain cancer treated using stereotactic radiosurgery (SRS), a minimally invasive, targeted form of radiosurgery used to treat brain tumors and other lesions. The SRS allows surgeons to define the coordinates of a tumor in the brain with precise accuracy.
The researchers used the SRS coordinates from 970 patients with approximately 3,200 brain metastatic tumors arising from skin, lung, breast, kidney or colon cancers treated at Keck Medical Center of USC from 1994-2015. They created two predictive mathematical models to analyze the exact locations of brain metastases based on the primary cancer origins.
One model showed that distinct regions of the brain were relatively susceptible to certain types of cancer; another provided the probability of each cancer metastasizing in certain brain regions. Both models resulted in the approximate same results as to which areas of the brain were most likely to develop cancer-specific tumors.
The researchers believe the results of the study could be useful in the eventual prevention and treatment of brain tumors.
Zada and Neman are currently using the data from this study to participate in an international trial involving multiple sites to further study the patterns of brain metastasis based on primary cancer type.