They find a way to slow down metastasis in the brain before there are symptoms

BarcelonaNew step in the fight against cancer. An international team of researchers led by the Brain Metastasis Group of the National Cancer Research Center (CNIO) of Spain has discovered a previously unknown phase of metastasis development that could be key to fighting brain cancer even before the first symptoms appear. According to the research, published in the journal Cancer Cell, before reaching the brain, these cells go through a stage in which they are especially vulnerable and could be effectively eliminated if attacked with the appropriate drugs.

In addition to the value of describing a previously unknown phase of metastasis development, the study has clinical implications, as it highlights a weak point of cancer cells that opens up possible ways to prevent metastasis from recurring after having been removed by surgery. It also allows for progress towards a long-awaited goal in oncology: stopping metastasis at such an early stage that it has not even shown symptoms, which de facto would be equivalent to preventing it.

Until now, it was known that colonizing cancer cells that reach another organ must adapt to an environment different from the tumor they come from, but it is such a hostile environment that many metastatic cells die during this adaptation. Now this study argues that the cells that manage to survive enter a period in which they perform a kind of hibernation that the authors have called "proliferative pause". A stage in which these cancer cells seek strategies to survive in the new environment, and temporarily abandon their aggressive nature.

According to the team of researchers –led by the head of the CNIO Brain Metastasis Group, Manuel Valiente, and involving more than seventy researchers from twenty institutions in Spain, the United Kingdom, Germany, France, and the United States–, this "pause" provides an opportunity to eliminate the seeds of brain metastasis when it is in a very incipient phase, before showing the first symptoms.

During the research, which has lasted six years, scientists have verified, first in mice and then in human brain metastasis samples, that these micrometastases –the seeds– can be eliminated with three drugs, two of which have already been approved for other indications.

The start of the race to prevent metastasis

This approach is not yet possible, because there are no diagnostic tests that reveal the presence of micrometastases, nor even biomarkers that alert to this risk. For this reason, Valiente has argued that discovering a phase in which incipient metastases are vulnerable "opens a window of opportunity to attack the disease before symptoms appear". The researcher is convinced that it is "the start of the race for the prevention of metastasis".

The study has focused on brain metastasis, but the researchers have pointed out, and will try to demonstrate in future studies, that this discovered stage of vulnerability could be common to the metastatic process in general.