2009-06-15

Researchers concluded that cancer patients should undergo vitamin D screening after a recent study found high prevalence of deficiency among subjects regardless of nutritional status.

Conducted at the Cancer Treatment Centers of America (CTCA) researchers assessed 737 cancer patients (302 male and 435 female) between January and June of 2008.

Subjects were evaluated and assigned to one of three classes of nutritional status: well nourished, moderately malnourished and severely malnourished. The mean age at presentation was about 56 years (SD = 10.2) and the most common cancer types were lung (133, 18%), breast (131, 18%), colorectal (97, 13%), pancreatic (86, 12%), prostate (44, 6%) and ovarian (38, 5%).

“While emerging evidence suggests the protective role of vitamin D in cancer, vitamin D status is not routinely assessed in cancer patients despite the high prevalence of malnutrition in this population,” said Carolyn Lammersfeld, national director of nutrition for CTCA and a principal investigator in the study.

Before the study, researchers hypothesized that malnutrition could contribute to vitamin D deficiency and therefore expected mean serum 25-hydroxy-vitamin D [25(OH)D] levels to be significantly lower in malnourished oncology patients. However, contrary to what they expected, vitamin D deficiency was found to be prevalent in cancer regardless of nutritional status.

This study was presented at the American Society of Clinical Oncology (ASCO) annual meeting and publicly released on ASCO’s website.

By Stephen Daniells, 03-Jun-2009

Related topics: Antioxidants, carotenoids, Vitamins & premixes, Cancer risk reduction

Increased intakes of vitamins C and E and beta-carotene may reduce the risk of cancer of the uterus, according to a new review and meta-analysis of the science to date.

Writing in Cancer Causes and Control, US scientists report that for every 1,000 microgram increase per 1,000 kcal of diet of beta-carotene was associated with a 12 per cent reduction in the risk of endometrial cancer.

Similarly, for every 50 milligram increase per 1,000 kcal of vitamin C the risk of endometrial cancer was reduced by 15 per cent, and for every 5 milligram increase per 1,000 kcal of vitamin E the risk of endometrial cancer was reduced by 9 per cent.

Endometrial cancer is the fifth most common cancer among women worldwide – around 7,000 American women die from the disease annually – but incidence of the cancer varies more than 10-fold worldwide.

The results are based on data from 12 case-control studies, and intakes from supplements were not considered by the researchers, led by Elisa Bandera from the Cancer Institute of New Jersey.

“Although the current case-control data suggest an inverse relationship of endometrial cancer risk with dietary intakes of beta-carotene, vitamin C, and vitamin E from food sources, additional studies are needed, particularly cohort studies, to confirm an association,” cautioned the researchers.
Indeed, data from one prospective cohort study “provided little indication of an association”, said Bandera and her co-workers.

Commenting on the potential mechanism, the US-based researchers noted that antioxidant vitamins may reduce the risk of cancer by limiting oxidative damage to DNA.
Antioxidant controversy

A vast body of epidemiological studies has linked increased dietary intake of antioxidants from fruits and vegetables to reduced risks of a range of diseases including cancer, cardiovascular disease and diabetes.

However, when such antioxidants have been extracted and put into supplements the results, according to the randomized clinical trials (RCTs), do not always produce the same benefits, and may even be harmful.

These observations have led to much negative publicity about antioxidant supplements, particularly the more well-known vitamin E and beta-carotene.

The design of randomised clinical trials, following the drug- or evidence-based model has received much criticism.

In an editorial comment in the Journal of the American Medical Association, Peter Gann, MD, ScD, from the University of Illinois at Chicago, said: “…single-agent interventions, even in combinations, may be an ineffective approach to primary prevention in average-risk populations.”

Bandera worked in collaboration with scientists from the University of Medicine and Dentistry of New Jersey, the American Cancer Society, and Kaiser Permanente

Source: Cancer Causes and Control
July 2009, Volume 20, Number 5, Pages 699-711doi: 10.1007/s10552-008-9283-x
“Antioxidant vitamins and the risk of endometrial cancer: a dose-response meta-analysis”
Authors: E.V. Bandera, D.M. Gifkins, D.F. Moore, M.L. McCullough, L.H. Kushi

Cancer Institute, Chinese Academy of Medical Sciences, Beijing, Peoples Republic of China.
BACKGROUND: The General Population Nutrition Intervention Trial was a randomized primary esophageal and gastric cancer prevention trial conducted from 1985 to 1991, in which 29,584 adult participants in Linxian, China, were given daily vitamin and mineral supplements. Treatment with “factor D,” a combination of 50 microg selenium, 30 mg vitamin E, and 15 mg beta-carotene, led to decreased mortality from all causes, cancer overall, and gastric cancer. Here, we present 10-year follow-up after the end of active intervention. METHODS: Participants were assessed by periodic data collection, monthly visits by village health workers, and quarterly review of the Linxian Cancer Registry. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the cumulative effects of four vitamin and mineral supplementation regimens were calculated using adjusted proportional hazards models. RESULTS: Through May 31, 2001, 276 participants were lost to follow-up; 9727 died, including 3242 from cancer (1515 from esophageal cancer and 1199 from gastric cancer). Participants who received factor D had lower overall mortality (HR = 0.95, 95% CI = 0.91 to 0.99; P = .009; reduction in cumulative mortality from 33.62% to 32.19%) and gastric cancer mortality (HR = 0.89, 95% CI = 0.79 to 1.00; P = .043; reduction in cumulative gastric cancer mortality from 4.28% to 3.84%) than subjects who did not receive factor D. Reductions were mostly attributable to benefits to subjects younger than 55 years. Esophageal cancer deaths between those who did and did not receive factor D were not different overall; however, decreased 17% among participants younger than 55 (HR = 0.83, 95% CI = 0.71 to 0.98; P = .025) but increased 14% among those aged 55 years or older (HR = 1.14, 95% CI = 1.00 to 1.30; P = .47). Vitamin A and zinc supplementation was associated with increased total and stroke mortality; vitamin C and molybdenum supplementation, with decreased stroke mortality. CONCLUSION: The beneficial effects of selenium, vitamin E, and beta-carotene on mortality were still evident up to 10 years after the cessation of supplementation and were consistently greater in younger participants. Late effects of other supplementation regimens were also observed.

J Natl Cancer Inst. 2009 Apr 1;101(7):507-18. Epub 2009 Mar 24

Departments of Urology, Institute for Human Genetics, University of California at San Francisco, San Francisco, California 94143-0794, USA.

PURPOSE: Dietary intake of long-chain omega-3 (LC n-3) polyunsaturated fatty acids may reduce inflammation and in turn decrease risk of prostate cancer development and progression. This potential effect may be modified by genetic variation in cyclooxygenase-2 (COX-2), a key enzyme in fatty acid metabolism and inflammation. EXPERIMENTAL DESIGN: We used a case-control study of 466 men diagnosed with aggressive prostate cancer and 478 age- and ethnicity-matched controls. Diet was assessed with a semiquantitative food frequency questionnaire, and nine COX-2 tag single nucleotide polymorphisms (SNP) were genotyped. We used logistic regression models to estimate odds ratios (OR) for association and interaction. RESULTS: Increasing intake of LC n-3 was strongly associated with a decreased risk of aggressive prostate cancer (P(trend)

Clin Cancer Res. 2009 Apr 1;15(7):2559-66. Epub 2009 Mar 24