Spanish researchers found a brief stage when early brain metastases may respond to treatment. Three drugs cleared microscopic lesions in mice and human tissue, but clinical trials are still needed.
After cancer cells reach the brain, many of them die. The CNIO team has now identified a short stage when some of the survivors become unusually vulnerable to treatment.
Researchers used three drugs to eliminate microscopic metastatic lesions in mice. They also confirmed the findings in human tumour samples. The work does not yet show that doctors can prevent brain metastases in patients. It gives researchers a defined target before the disease becomes detectable.
The window is brief.
Исследование в Nature, опубликованное в 2016 году, показало, что связь клеток опухоли с астроцитами через gap junctions помогает мозговым метастазам выживать и расти. Этот механизм стал одним из важных ориентиров для последующих работ группы CNIO.
The discovery focuses on what happens after cells travel from a primary tumour such as lung cancer, breast cancer or melanoma. The new environment is hostile. Many invading cells die.
The cells that survive enter what the researchers call a "proliferative pause." They temporarily stop acting like aggressive tumour cells while they adjust to their new surroundings.
That pause creates an opening. The treatment blocked molecular mechanisms that help the cells adapt. Early metastatic seeds then failed to develop into detectable brain metastases in animal models.
Two of the three drugs already have approval for other medical uses. Their use to prevent brain metastasis has not been established.
The study appeared in Cancer Cell after six years of work led by Manuel Valiente, who heads the CNIO Brain Metastasis Group. More than 70 co-authors from around 20 institutions in Spain, the United Kingdom, Germany, France and the United States took part.
Крупный анализ более 150 000 опухолевых образцов из шести типов рака, опубликованный в Neuro-Oncology 26 сентября 2026 года, показал, что мозговые метастазы часто связаны с высокой мутационной нагрузкой и изменениями в TP53 и пути MAPK. Это поддерживает идею о том, что метастазы в мозг могут иметь отдельные молекулярные особенности и требовать самостоятельного терапевтического подхода.
A major obstacle remains. Doctors cannot currently find these microscopic deposits through routine diagnostic tests. No biomarkers reliably show that they are present or that they are likely to develop.
Without that warning system, researchers cannot treat every patient who might harbour an invisible metastasis. A 2026 review in Neuro-Oncology also describes brain colonisation as a multistep process. After tumour cells cross the blood-brain barrier, they must adapt metabolically and epigenetically to the local environment before sustained growth can begin.
The reason is simple.
This work is better viewed as the start of a prevention strategy than as a ready-made therapy. Researchers have shown the vulnerability before symptoms appear in experimental models. Clinical trials must still establish whether the approach is safe and effective in patients.
Other studies are examining how neuronal activity and contact between tumour cells and brain cells may promote invasion. Those mechanisms remain research targets. They are not established preventive treatments.
The findings may also address relapse after surgery. During a later phase of the project, the molecular activity seen in the vulnerable pause resembled the behaviour of invasive fronts in established human metastases.
The same drugs restrained those advancing fronts in experiments. That result suggests a possible way to test preventive treatment in patients at risk of recurrence after an operation.
Validation went beyond mice. Researchers treated living samples through RENACER, the Spanish National Brain Metastasis Network created by Manuel Valiente in 2021. The results supported the therapeutic effect.
The wider issue of moving existing medicines into new clinical settings has also appeared in earlier health reporting. That report concerned different diseases and treatments.
A review in Medical Oncology published on 29 August 2026 also identifies neuro-immune and neuronal interactions as promising areas for brain-metastasis research, particularly in lung cancer.
External experts called the evidence for the pause-control mechanism and its possible drug and genetic modulators robust. They also said some elements need more research.
The experiments reduced metastatic burden. They did not prove complete and lasting eradication.
The CNIO group plans to pursue clinical trials aimed at preventing brain metastasis. The study identifies a biological weakness and drugs that can exploit it, which gives researchers a basis for the next step.
It is not proof that recurrence can be stopped in people. The more precise point is this: oncology may now be able to test prevention while metastatic cells are adapting, before the disease becomes visible and aggressive.
