Every two minutes, a woman will be diagnosed with breast cancer in the United States. This means that over 250,000 new cases of breast cancer will be diagnosed each year. As this disease is the second leading cause of death in women, steps need to be taken in order to help prevent breast cancer and improve treatment outcome. According to research, vitamin D could be part of the solution.
Overall, numerous studies have pointed out vitamin D’s role in reducing breast cancer risk, improving treatment outcomes and survival. Vitamin D is thought to mediate some forms of cancer by controlling cell functions, including cell proliferation. Additionally, vitamin D has also been associated with both inflammatory and estrogen-related pathways that have been linked to incidence of cancer.
In a recent study, researchers evaluated the effect of vitamin D status during neoadjuvant chemotherapy on responsiveness to treatment. Researchers included a group of 144 women with stage I, II or III breast cancer. In order to be included in the study, the women had to have had their vitamin D levels tested at diagnosis of their cancer and undergone surgery between October of 2009 and December of 2015 at the University of Iowa Holden Comprehensive Cancer Center or between March 2007 and August 2008 at the Institut Régional du Cancer in Montpellier, France.
The participants had undergone neoadjuvant chemotherapy (NAC), which is a treatment designated to shrink tumors prior to surgical removal. Additionally, all participants had available pathological complete response status (pCR) available. This is the measurable response of tumors to chemotherapy treatment, and is a common predictor for long-term survival.
This is what the researchers found:
- Average vitamin D status was 23 ng/ml (57.5 nmol/l).
- Approximately ⅓ of the women achieved complete response to NAC, meaning the treatment was effective in reducing tumor size.
- Vitamin D deficiency (<20 ng/ml; 50 nmol/l) was associated with a nearly threefold increased odds of poor treatment response compared to those with sufficient status (95% CI: 1.34 – 6.62).
- Higher stage of cancer, presence of cancer in lymph nodes and older age were associated with a 2.63, 2.86 and 1.5 increased odds of not attaining response to treatment, respectively.
The researchers concluded,
“In this retrospective cohort analysis of women with operable breast cancer, vitamin D deficiency at initiation or early in the course of NAC was associated with not attaining a pCR.”
“Vitamin D supplementation during NAC may benefit patients receiving NAC by increasing its therapeutic efficacy.”
Approximately one in eight women will develop breast cancer within their lifetime. This study, and many before it, have supported a beneficial role of maintaining higher levels of vitamin D in women with breast cancer. Though this relationship has yet to be proven as causal, the many associations between breast cancer and vitamin D warrant public action.
Of course, all individuals should maintain a healthy vitamin D status between 40 – 80 ng/ml (100 – 200 nmol/l), but it may be especially important for postmenopausal women, women with a family history of breast cancer or women currently battling breast cancer to supplement with vitamin D. The Vitamin D Council recommends supplementing with between 5,000 – 10,000 IU (125 – 250 mcg) per day in order to maintain optimal health.
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Peterson, R. & Cannell, JJ. Higher vitamin D levels were associated with improved treatment response in breast cancer patients. The Vitamin D Council Blog & Newsletter, 1/2018.