An Irish-led study has discovered a potential new way to treat secondary breast cancer that has spread to the brain using existing drugs.

The study was led by researchers at RCSI University of Medicine and Health Sciences and the Beaumont RCSI Cancer Center (BRCC), who collaborated with the Mayo Clinic and University of Pittsburgh in the US.

Most breast cancer-related deaths are due to treatment relapse, which leads to a spread of tumours to many organs around the body. When secondary (metastatic) breast cancer spreads to the brain, it can be particularly aggressive. Some patients will have just months to live.

This new study focused on genetically tracking tumour evolution in cancer patients - from diagnosis of the primary tumour in the breast to the metastatic spread in the brain. The researchers found that almost half of the tumours had changes in the way they repair their DNA, making these tumours vulnerable to an existing type of drug known as a PARP inhibitor.

PARP inhibitor drugs work by preventing cancer cells from repairing their DNA, which results in the cancer cells dying.

According to the study’s principal investigator, Prof Leonie Young, current treatment options for people with breast cancer that has spread to the brain are “inadequate”. As a result, research that focuses on expanding options for these patients is “urgently needed”.

“Our study represents an important development in getting one step closer to a potential treatment for patients with this devastating complication of breast cancer,” she said.

The study was funded by Breast Cancer Ireland, with support from Breast Cancer Now and Science Foundation Ireland. According to Breast Cancer Ireland CEO, Aisling Hurley, the results “show evidence of the real value and impact our funds are having”.

“It also points to the ongoing importance of scientists and clinicians working closely together with a view to developing newer, targeted therapies for the many different subtypes of breast cancer experienced, so that we can transform this disease into a treatable illness that can be maintained long term. This is exactly the type of research that will help us to truly change the landscape of this disease into the future,” she commented.

The study is published in the journal, Nature Communications, and can be viewed here.