Vitamin D deficiency found in advanced cancer patients

People who have advanced cancer are more likely to have low levels of vitamin D, according to research presented today at the 53rd American Society for Radiation Oncology (ASTRO) Annual Meeting.

The researchers found that nearly three out of four cancer patients referred for radiotherapy treatment had less than the recommended level of vitamin D (30ng/mL) in their blood. Also, those with more advanced cancers (stage III) had the lowest levels of vitamin D. However, the same association was not found for stage IV cancers, the most advanced stage of cancer.

Dr Virginia Warren, Assistant Medical Director, Bupa, said: "We know that vitamin D is beneficial for good bone health. However, whether vitamin D is also beneficial in preventing cancer remains controversial. Evidence is growing that having insufficient or deficient levels of vitamin D may increase your risk of various cancers.

"In this relatively small study, a link has been made between low levels of vitamin D and more advanced stages of cancer. But what we don’t yet know is what comes first – does having advanced cancer cause a vitamin D deficiency, or is a vitamin D deficiency causally related to developing advanced cancer? Although this study makes a contribution to the overall vitamin D and cancer debate, it really only suggests a small part of the story, as we don't know whether giving the patients vitamin D supplement had any impact on their prognosis. Other researchers are addressing this question. An example is a study looking at the effect of vitamin D treatment over three years for patients with skin cancer (melonoma), which has been surgically removed. This is being done by a group of Italian researchers led by Dr Testori in Milan.

“Given the present state of knowledge about vitamin D and health, people in the UK should aim to spend some time in the sun in the middle of each day in summer in short sleeves and without sunscreen, being careful to avoid reddening of their skin. In the winter, and for those who for cultural or other reasons can't bare their skin, people should consider taking a vitamin D supplement – two high-strength (12.5 microgram) capsules is appropriate for adults. Those who spend lots of time indoors, always cover all their skin and/or have dark skin might want to discuss whether or not they have vitamin D deficiency with their GP. If so, this would need treatment rather than supplementation.”

This study included 160 male and female cancer patients who had been referred for radiotherapy treatment in the USA. The types of cancer they had included breast, prostate, lung, thyroid, bowel and other types of the disease. Most of the people had stage I or stage II cancer. Each person had a blood test to determine their vitamin D levels within 90 days of their initial consultation.

Of these people, 73.8 percent had low levels of vitamin D, less than 30ng/ml, and 31.9 percent of these people had less than 20ng/ml. The researchers considered the optimal level of vitamin D to be 30ng/ml. The people who had low levels of vitamin D were given a vitamin D supplement for eight weeks. These results are yet to be made public.

When analysing the results, the researchers took into account other factors such as age, sex and the time of year they checked vitamin D levels, but they didn't take into account previous cancer treatments (if any). This may have had an impact on vitamin D levels.