In 2008, breast cancer killed 458,503 women worldwide. The incidence of breast cancer varies greatly around the world; the further you live from the equator, the higher the risk. Rates have increased significantly since the 1970s.
In 2009, Professor Cedric Garland’s group at the University of California at San Diego estimated that maintaining a 25(OH)D level between 40-60 ng/ml would prevent 75% of new cases in the USA.
However, vitamin D deficiency among breast cancer patients remains rampant. Dr. William Jacot and colleagues from Montpellier, France, recently measured vitamin D levels in 77 breast cancer patients. They found that 80% of all patients at the time of diagnosis were vitamin D deficient (<30 ng/ml) with 40% having levels below 20 ng/ml and 10% had levels below 10 ng/ml.
Jacot W, Pouderoux S, Thezenas S, Chapelle A, Bleuse JP, Romieu G, Lamy PJ. Increased prevalence of vitamin D insufficiency in patients with breast cancer after neoadjuvant chemotherapy. Breast Cancer Res Treat. 2012 May 6.
Regrettably, after 18 months of standard chemotherapy, a period that included two summers, vitamin D levels were remarkably lower. After chemotherapy, 97% of all patients were deficient, with 50% below 20 ng/ml and almost one-fourth below 10 ng/ml. What happened to their vitamin D?
One explanation is that the women stopped going outside after diagnosis or that the chemotherapy drugs interacted with vitamin D. However, another explanation is that the breast cancer used up the vitamin D in fighting the breast cancer. Indeed, the authors state, “Many data support the hypothesis that vitamin D might have anti-cancer activity in breast cancer.”
To be sure, studies confirm that at diagnosis, patients with higher levels of vitamin D do better and live longer, and this includes breast, lung, colon, and prostate cancer This implies a treatment effect.
I do not understand why we must wait for randomized controlled trials while these women suffer and die. It appears from the above study by Jacot et al that some oncologists may not be giving any vitamin D at all. Instead, they are letting levels fall into the osteomalatic (adult rickets) range during chemotherapy. And osteomalacia is a painful disease.