Sometimes hormone-receptor-positive breast cancer comes back or grows during treatment with hormonal therapy. Abnormal genes give breast cancer cells the ability to grow, divide, and spread uncontrollably. The abnormal genes that make cells cancerous also make them more likely to have still more abnormal genetic changes. This partly explains why breast cancer treatments stop working and why everyone doesn't get the same benefits from a treatment. In this study, the cancer cells changed so they weren't affected by hormones, so that reducing the amount of hormones or blocking their effects with hormonal therapy wouldn't work anymore.
A small study suggests that the targeted therapy medicine Nexavar (chemical name: sorafenib) may be able to make hormone-receptor-positive breast cancers that have stopped responding to hormonal therapy start responding again.
Nexavar was given to 27 women diagnosed with hormone-receptor-positive breast cancer that came back or grew during treatment with Arimidex (chemical name: anastrazole), an aromatase inhibitor that is one type of hormonal therapy. After Nexavar treatment, about 25% of the cancers seemed to respond again to Arimidex. The findings were reported during the 2008 American Society of Clinical Oncology (ASCO) Breast Cancer Symposium.
Nexavar is a targeted therapy approved to treat liver cancer. Nexavar is not approved to treat breast cancer.
Nexavar is a kinase inhibitor; kinases are certain proteins inside a cell that can stimulate the cells to grow uncontrollably. Nexavar works by interfering with kinases inside the cancer cell, which limits the amount of energy the cells have to grow and multiply. Other research suggests that changes in kinase proteins may be why hormone-receptor-positive breast cancers stop responding to hormonal therapy. Nexavar may reduce the effect of the altered kinases and make the cancer respond again to hormonal therapy.
While this study is promising, it is very small. More research is needed to figure out how targeted therapies like Nexavar might be used with other breast cancer treatments to offer more benefits.
Stay tuned to Breastcancer.org for the latest news on research to prevent, diagnose, and treat breast cancer.