According to an early online publication in the Journal of Clinical Oncology, expression of certain genes may be able to identify individuals with early breast cancer who are at an increased risk of their cancer spreading to the bone. Although further study is necessary to confirm these findings, patients at a high risk of developing spread to the bone may benefit from early treatment with bisphosphonates.
Breast cancer is diagnosed in approximately 200,000 women annually in the U.S. alone. Fortunately, if cancer is detected and treated early, cure rates are high following standard therapy.
Node-negative breast cancer refers to the earliest stages of breast cancer in which the cancer has not spread to the axillary (under the arm) lymph nodes. Although women with node-negative breast cancer typically have an excellent prognosis, some women will experience a recurrence of their cancer and succumb to their disease. One site that cancer may spread is to the bone, referred to as bone metastasis. There are no curative standard therapies in the treatment of bone metastasis; treatment is aimed at improving the duration of survival and maintaining quality of life.
Bisphosphonates are agents that can reduce the rate at which bone fractures occur and delay the onset of immobility caused by bone metastasis. Researchers continue to evaluate using bisphosphonates earlier in the course of certain cancers in an attempt to reduce the risk of bone metastasis or ultimately prevent bone metastasis from occurring in some patients.
Researchers from the Netherlands recently conducted a clinical trial to evaluate the expression of specific genes that may be associated with the risk of bone metastasis among women with node-negative breast cancer.
This study included 107 samples of breast cancers among patients diagnosed with node-negative breast cancer who subsequently developed metastasis to different sites in the body. The expression of genes was compared among those who developed bone metastasis and those who developed metastasis elsewhere.
- A classifier of 30 genes was correctly associated with all individuals whose cancer recurred to the bone (100% sensitivity).
- These genes had a specificity of 50% (they identified 100% of individuals whose cancer spread to bone, but 50% of cancers with this gene set had spread elsewhere in the body).
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The researchers concluded that gene expression may ultimately be able to determine the risk of women with node-negative breast cancer developing bone metastasis. These women may ultimately benefit from early use of bisphosphonates. However, the researchers caution that further studies to confirm these findings are necessary.
Women with breast cancer may wish to speak with their physician regarding their individual risks and benefits of participating in a clinical trial further evaluating gene expression and possible associations with outcomes. Two sources of ongoing clinical trials include the National Cancer Institute (www.cancer.gov) and www.cancerconsultants.com.
Reference: Smid M, Wang V, Klijn J, et al. Genes Associated With Breast Cancer Metastatic to Bone. Journal of Clinical Oncology. Early online publication April 24, 2006. DOI: 10.1200/JCO.2005.03.8802.
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