A group from the University of Toronto reported the first human trials of a deltanoid (vitamin D compound) that appear to both help fight prostate cancer and to fight that cancer without causing any side effects.
This year, about 400,000 American men will learn they have prostate cancer, making it the leading cancer among men. Early diagnosis is important as surgery or radiation can be curative. Early diagnosis is helped by measuring PSA, a blood marker for possible prostate cancer. If a biopsy is positive, then surgery or radiation leads to falling PSA levels and hope for a cure. After such treatment, urologists then use PSA as a marker for tumor reoccurrence and progressive disease. If the treatment is not curative and the cancer continues to grow, the PSA often goes up again leading to castration, either surgical or chemical. Then the PSA often falls again indicating a remission. Castration can delay the cancer from spreading for several years, but then, if the cancer grows again, the PSA again marches steadily upwards and treatment options become quite limited, leading to hopelessness. Throughout the battle with prostate cancer, PSA is the standard clinical marker for progressive disease. This year, thousands of American men go down the hopeless road marked by progressive rises in PSA. About 40,000 will die, making prostate cancer the second leading cancer killer of American men.
Dr. Woo and his colleagues in Toronto have finally given these men and their families reason to hope. The senior investigator of the study, Dr. Reinhold Vieth, presented the first human trial of cholecalciferol ever reported in any cancer, as well as the best clinical results of any vitamin D compound ever tested in any human cancer. Woo, Vieth and colleagues studied 15 men with biopsy proven prostate cancer who had undergone surgery or radiation but who had started down that hopeless road marked by three progressive increases in PSA levels. The researchers gave all the patients 2,000 units of cholecalciferol (the plain, cheap, simple, natural, available at any health food store, form of vitamin D) every day for up to 21 months. In the majority of men, their PSA either went down or stopped going up, suggesting their prostate cancer either started to regress or remained quiescent!
The Toronto researchers found evidence of a clinical response in 14 of the 15 men as confirmed by a prolongation of their PSA doubling time. What's more, none of the men had any side effects, of any kind. Again, this is the best result yet obtained for any vitamin D compound in any human cancer trial. For example, let's compare Vieth's result to any earlier trial of a vitamin D compound reported by a Stanford University Group in 1998. The Stanford group gave a very different form of vitamin D [activated vitamin D (calcitriol), a dangerous form of vitamin D known to cause high blood and urine calcium] to seven men in the same stage of prostate cancer. They also used PSA as a marker of tumor responsiveness. After getting the calcitriol, the PSA of the men continued to increase, although more slowly. One of the patients showed a transient decrease in PSA but he had to be withdrawn from the study due to side effects from calcitriol. Unlike the Toronto study, none of the Stanford patients showed a prolonged flattening or a prolonged decrease in their PSA. All of the Stanford patients developed side effects such as high urine calcium, and one developed a kidney stone.
Therefore, the University of Toronto beat Stanford University, hands-down. Moreover, they did so with much lower comparable doses of deltanoids (deltanoids are a generic term for vitamin D compounds). The Stanford group gave increasing doses of the most potent and most dangerous deltanoid (the steroid hormone, calcitriol). They gave as much as the patients could tolerate until their urine calcium got too high. The Toronto group gave a fixed low dose (2,000 units) of the prehormone, cholecalciferol, a very safe compound that never causes high calcium in the doses used. In fact, the lowest dose of cholecalciferol known to cause high blood calcium is more than 20,000 units. Therefore, the Toronto group got better results with one-tenth the comparable dose of deltanoids! Vieth wanted to use more cholecalciferol but widespread ignorance about the physiology and pharmacology of vitamin D remains and he could not get adequate dosing past the various review committees.
In fact, 2,000 units of cholecalciferol a day will raise the "average" calcidiol [25(OH)D] level to about 40 ng/mls, now considered by most authorities to be the lower limit of adequate vitamin D nutrition. "Average" means half above and half below, which also means 50 % of the Toronto men were still below 40 ng/mls; that is, one-half of the Toronto men with prostate cancer may still have been vitamin D deficient after treatment. Robert Heaney proved that adequate treatment of vitamin D deficiency requires about 4,000 units of vitamin D every day. Said another way, it takes 4,000 units of cholecalciferol to assure that 97.5 % of healthy subjects will become vitamin D replete.
Given these results, what would evidence based medicine have us do? (Evidence based medicine is a new mantra which decries doctors from any treatment that is not rigorously scientifically proven). The evidence based medicine folks say one open study of 15 patients is hardly rigorous proof (the Vitamin D Council agrees); more trials are needed (the Vitamin D Council agrees); falling PSA does not prove the tumor is regressing (the Vitamin D Council agrees) and Vieth's study has only been presented, not published and should be viewed with skepticism (the Vitamin D Council agrees). Finally, the evidence based medicine folks say that doctors should not give cholecalciferol to prostate cancer patient until rigorously conducted scientific trials prove vitamin D helps cure prostate cancer. That is, the evidence based medicine folks say urologists should allow prostate cancer patients to die before treating them with cholecalciferol. The Vitamin D Council disagrees and we know some plaintiff attorneys who disagree as well.
You see, the question is not "Should men with prostate cancer be treated with vitamin D?" The question is, "Should men with prostate cancer be allowed to die vitamin D deficient?" The evidence based medicine folks say they should. We say they shouldn't. All patients with prostate cancer should have their vitamin D deficiency aggressively and immediately corrected and that requires up to 4,000 units of cholecalciferol every day. Physicians, researchers, or scientists who say 4,000 units may be toxic are simply admitting their ignorance of current scientific literature.
Physicians who have read the recent scientific literature and who understand the physiology and pharmacology of cholecalciferol would be comfortable using up to 10,000 units of cholecalciferol a day while following the patient's PSA, urine and serum calcium, and 25(OH)D. Thanks to the Toronto group, scientific evidence now exists that suggests such an approach may help prostate cancer patients; only time will tell.
Many patients with prostate cancer are on the long hopeless road towards death. Not only may plain old vitamin D help men with prostate cancer, it is likely to give them back their hope. Physicians have many rights, but the right to take away hope is not among them.
Article written by The Vitamin D Council