A new way to treat lethal metastatic breast cancer which has spread to the brain, by using an already existing anti-cancer drug, has been discovered by researchers at the Royal College of Surgeons in Ireland (RCSI).
here are 690 deaths from breast cancer in Ireland each year, say Breast Cancer Ireland, which funded the research along with Breast Cancer Now and Science Foundation Ireland. The research was carried out in collaboration with the Mayo Clinic and the University of Pittsburgh.
Most deaths from the disease result from the spread of tumours to organs around the body such as the liver, lungs or bones. When breast cancer spreads to the brain, it can be particularly aggressive.
“With a confirmed diagnosis of breast cancer we would expect to have a life expectancy between 12 and 24 months,” said Prof Leonie Young, lead investigator for the project at Beaumont RCSI Cancer Centre, with Dr Nicola Cosgrove, Dr Damir Varešlija and Prof Arnold Hill.
“It’s absolutely devastating,” said Prof Young. “And the terrible thing is that there’s currently really no targeted therapy for women with this disease. The main treatment is surgery or radiation. That’s where they just focus on the actual tumour mass.”
Prof Young added: “The success of surgery depends on where in the brain the tumour is. The tumour can go to various regions of the brain.”
The risk of breast cancer spreading to the brain is highest for aggressive cancer types such as HER2-positive, or triple-negative breast cancer, and new treatment options here are sorely 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,” Prof Young said.
About 10 to 15pc of women with Stage 4 breast cancer develop brain metastases. In most of these women, cancer has already spread to other organs such as the liver, lung or bones, but for about 17pc of these women, the brain is the only place cancer has spread to.
An MRI scan can usually determine whether cancer has spread to the brain. The symptoms of breast cancer include headache, slurred speech, blurred vision, balance problems, memory difficulties, mood changes, seizures, or stroke.
The RCSI study tracked changes in breast cancer as it moved into the brain. Researchers found that, when the tumours reached the brain, they changed in a way that made them vulnerable to a known drug.
This drug, called a PARP inhibitor, which is approved for use in cancer treatment, works by preventing cancers from being able to repair their DNA, which results in the death of cancer cells.
The research has provided a new option for women with breast cancer which has spread to the brain. Prof Young said that clinical trials to test PARP inhibitors are planned, and she is hopeful that this can lead to “significant improvements in patient survival outcomes”.
Dr Varešlija added: “By uncovering these new vulnerabilities in DNA pathways in brain metastasis, our research opens up the possibility of novel treatment strategies for patients who previously had limited targeted therapy options.”