QIMR Berghofer researchers have discovered why some triple negative breast cancer patients do not respond to a common chemotherapy drug and say a simple blood test could help determine the best treatment.
The study led by QIMR Berghofer Medical Research Institute’s Tumour Micro-environment group, which is headed by Associate Professor Andreas Möller, examined why the commonly used chemotherapy doxorubicin worked on some women with triple negative breast cancer, but not on others.
Triple negative breast cancer accounts for about 15 per cent of all breast cancer cases and is most commonly treated with chemotherapy.
Lead author, Associate Professor Adrian Wiegmans, said the study found that doxorubicin did not kill breast cancer cells in women with high levels of the protein prion in their blood and found the drug would bind onto the protein instead of the cancer cells.
“Doxorubicin is the front-line chemotherapy treatment given to the majority of women with triple negative breast cancer around the world, but up to 78 per cent of patients who undergo extended treatment develop resistance and relapse,” Associate Professor Wiegmans said.
“Based on this study, we believe early screening for prion levels in the blood would allow doctors to choose an alternative chemotherapy to doxorubicin and save patients from undergoing ineffective treatment and needlessly suffering side effects.”
Associate Professor Möller said the abundance of prion protein did not negate the effectiveness of another closely related chemotherapy, epirubicin, so doctors could instead choose that as the first treatment option.
“Drug resistance is a serious problem for cancer patients and the ability to know if a patient will respond to a treatment is a huge advantage in fighting the disease.” Associate Professor Möller said.
“We hope that in future, triple negative breast cancer patients will be screened for this protein when they are diagnosed to help guide what treatment should be offered, and to eliminate what won’t work.
Associate Professor Wiegmans said the study could have implications for several other cancers where doxorubicin was used, such as bladder, stomach, lung, ovarian, and thyroid cancers and some types of leukaemia and Hodgkin’s lymphoma.
Doxorubicin has been used in the United States since 1974 and is included on the World Health Organization’s List of Essential Medicines that are considered the most effective and safe medicines needed in a health system.
Associate Professor Wiegmans said the study findings would have implications for triple negative breast cancer patients around the world because chemotherapy resistance drove the recurrence and spread of cancer.
“Women who relapse with triple negative breast cancer have a terrible prognosis of less than six months survival, so the ability to predict which patients will gain from treatment is the goal for all doctors,” he said.
The study was funded by the National Health and Medical Research Council.
It has been published in the journal JCI Insight.