Triple-negative Breast Cancers More Likely to Spread to Brain
Women with triple-negative breast cancer (estrogen receptor-, progesterone receptor-, and human epidermal receptor-negative) have a higher risk that cancer will spread to the brain. These results were recently published in the journal Breast Cancer Research.
The majority of breast cancers are hormone-positive breast cancers, meaning that the cancer cells are stimulated to grow from exposure to the female hormones estrogen and/or progesterone. Women with hormone-positive breast cancer are treated with hormone therapy, which prevents or reduces the formation of estrogen in the body or prevents estrogen from binding to the cell and stimulating growth. The stimulation of progesterone on hormone-positive cancer cells is affected by estrogen receptor activity; therefore, if estrogen exposure is reduced, progesterone sensitivity is often also affected.
The human epidermal growth factor receptor 2 (HER2) is a biologic pathway that is also involved in replication and growth of a cell. HER2-positive breast cancers, which account for approximately one-fourth of breast cancers, overexpress HER2 receptors. These cancers are treated with agents that target the receptor to slow growth and replication.
The brain is a common site to which breast cancer spreads (metastasizes). Because patients with brain metastases are considered incurable with standard treatment approaches, researchers are trying to identify risk factors for developing brain metastases and potential ways to prevent them.
Breast cancer that is estrogen receptor (ER) negative, progesterone receptor (PR) negative, and HER2-negative is referred to as triple negative. Patients with triple-negative breast cancer have fewer treatment options than patients with either hormone-positive or HER2-positive disease. Their options are mainly chemotherapy and/or radiation therapy.
Researchers from the National Cancer Center in Korea recently evaluated data involving women with breast cancer to explore possible relationships between triple-negative breast cancer and outcomes compared with other forms of breast cancer. The study included 805 patients with advanced breast cancer who were treated between 2001 and 2006. Data regarding survival, metastasis, and receptor status were compared between patients with different subtypes of breast cancer.
- Patients with triple-negative breast cancer had the highest rates of brain metastases (37%).
- Survival following a cancer recurrence to the brain was also lowest among patients with triple-negative cancer.
- Survival overall was lowest among women with triple-negative cancer.
The researchers concluded that women with triple-negative breast cancer have a greater risk of developing brain metastases and have a worse prognosis following brain metastases than other subgroups of breast cancer. Further research into treatment for triple-negative breast cancers is warranted.
Reference: Nam B-H, Kim S Y, Han H-S, et al. Breast cancer subtypes and survival in patients with brain metastases. Breast Cancer Research. 2008, 10:R20doi:10.1186/bcr1870.
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