According to the American Cancer Society, estimates for 2011 predicts the diagnosis of 230,480 new cases of invasive breast cancer and 57,650 cases of non-invasive breast cancer. Many postmenopausal women diagnosed with breast cancer are treated with Femara, an aromatase inhibitor drug. This drug has been linked to an increased risk of bone loss and vitamin D deficiency in patients and requires regular monitoring of blood levels. Vitamin D deficiency in these patients causes musculoskeletal symptoms such as joint pain and stiffness, bone and muscle pain and muscle weakness. It is unclear as to whether Femara causes the vitamin D deficiency or if it is caused by the breast cancer.
Femara
Femara is a drug classified as an aromatase inhibitor. According to the National Cancer Institute, aromatase inhibitors block the production of estrogen made in the body's tissues. They are unable to block estrogen made in the ovaries, which is why they are only used in postmenopausal women. Many breast tumors are sensitive to estrogen, and it is estrogen that helps them grow. By blocking the estrogen, the growth of these tumors is essentially blocked. Possible side effects of Femara are hot flashes, bone pain, back pain, joint pain, nausea, fatigue, shortness of breath and coughing.
Vitamin D
Vitamin D is a fat-soluble nutrient that can be made by the body through the exposure of skin to ultraviolet B rays from the sun. It is also found in fortified milk and oily fish such as salmon. Vitamin D is essential for bone health and aids in the body's absorption of calcium. A deficiency in vitamin D can lead to symptoms such as bone pain and muscle weakness. Severe vitamin D deficiency can lead to osteomalacia, which is softening of the bones. Vitamin D deficiency has been linked to breast cancer risk. A 2011 study published in the "American Journal of Epidemiology" showed a link between vitamin D production through sun exposure and a reduced breast cancer risk. They concluded that increased cutaneous production of vitamin D throughout adolescence and adulthood reduced the risk of breast cancer.
Medical Research
Many studies have looked at the connections between vitamin D deficiency, breast cancer and aromatase inhibitors such as Femara. A 2010 study published in "Maturitas" examined vitamin D deficiency and bone mineral density in postmenopausal women taking aromatase inhibitors. The study evaluated 232 women with early breast cancer who were currently receiving treatment with an aromatase inhibitor. At the baseline, 88.1 percent of the women had low vitamin D levels, and 21.2 percent were severely deficient. The study concluded that vitamin D deficiency is commonly undiagnosed in patients with early breast cancer who are receiving treatment with an aromatase inhibitor such as Femara and that there is a need for routine vitamin D monitoring and supplementation to reduce the risk of bone loss.
Considerations
While it is unclear if Femara is the actual cause of vitamin D deficiency in breast cancer patients, the two have a definite association between them. If you are taking Femara to treat your breast cancer, consult with your physician and have your serum vitamin D levels tested. If the results show you are vitamin D deficient, your physician will be able to treat the deficiency with high doses of vitamin D supplementation. Once your levels are within the optimal range, your physician will design a supplemental treatment plan to maintain healthy levels of vitamin D and reduce your risk of bone loss, muscle and bone pain and muscle weakness.
References
- American Cancer Society; How Many Women Get Breast Cancer; June 2011
- National Cancer Institute: Aromatase Inhibitors
- Chemo Care: Femara
- Office of Dietary Supplements: Vitamin D
- "American Journal of Epidemiology"; Ultraviolet Sunlight Exposure During Adolescence and Adulthood and Breast Cancer Risk: A Population-based Case-Control Study Among Ontario Women; LN Anderson, et al.; June 2011
- "Maturitas"; Vitamin D Deficiency and Bone Mineral Density in Postmenopausal Women Receiving Aromatase Inhibitors for Early Breast Cancer; X. Noques, et al.; July 2010
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