There has been a recent media frenzy regarding the relationship between Vitamin D and melanoma, due to a new study published in The Journal of Clinical Oncology.  This has added heat to an already fiery debate: On one side are the proponents of sun abstinence, who advocate that sunlight should be avoided, as sun exposure has clearly been proven to increase the risk of skin cancers.  On the other side are the proponents of Vitamin D, who believe that, since Vitamin D deficiency is reaching staggering proportions, minimal sun exposure is necessary to avoid the consequences of Vitamin D deficiency (these include osteoporosis, fatigue, and many newly speculated associations to chronic disease).

Now, new research seems to have found an association between higher levels of Vitamin D and increased melanoma survival.  According to the article “Vitamin D May Improve Melanoma Survival”, posted on September 26th, 2009 at forbes.com:

“Higher levels of vitamin D are linked to less severe, less deadly melanoma lesions in people with skin cancer, new research suggests.

The findings provide more support for the idea that vitamin D is crucial to skin health. Many Americans, however, don’t get enough of it, perhaps because they limit sun exposure and drink less milk than in the past.

“Although avoiding sunburn is very important in order to prevent melanoma, it is also important to avoid becoming deficient in vitamin D,” said Dr. Julia A. Newton-Bishop, a dermatology professor at the University of Leeds in England and a study co-author. “This is especially important for melanoma patients in whom low vitamin D levels appear to be harmful.”

Newton-Bishop and her research colleagues looked at the medical records of 872 people with melanoma and tried to link their vitamin D levels to the severity of their lesions and their likelihood of surviving without a relapse.

Those with higher levels of vitamin D in their bodies had less severe lesions — the lesions were thinner — and a lower rate of relapse, the researchers found.

The results are reported in the Sept. 14 issue of the Journal of Clinical Oncology.

“The research suggests that low levels of vitamin D allow the melanoma tumors to grow better and, therefore, to be more of a threat to the patient,” Newton-Bishop said.

It’s not clear how food, sun exposure and supplements contributed to the higher levels of vitamin D in some people, although they did take more multivitamins and cod liver oil, she said.

Melanoma is the cause of most skin cancer deaths, even though it accounts for less than 5 percent of skin cancer cases. The best way to prevent melanoma is by avoiding excessive sun exposure.

To boosts levels of vitamin D, people with melanoma should take daily supplements, the authors concluded, and consume foods that contain vitamin D, such as fatty fish and some fortified cereals.

The study is provocative and “somewhat contrary to traditional thinking,” said Dr. Adit Ginde, an assistant professor of surgery at the University of Colorado Denver School of Medicine. More work needs to be done to prove that vitamin D levels directly affect skin cancer development and to determine if increasing the levels will help people with melanoma, he said.

Vitamin D appears to be more than a cancer fighter. Low levels of vitamin D have been linked to a variety of health problems, including heart disease, infections, and poor overall health. And adults with low levels may suffer from lower bone mineral density.

But researchers have noticed that vitamin D deficiency has been on the rise in recent decades. An earlier study led by Ginde found that more than 75 percent of Americans don’t have high enough vitamin D levels, with African-Americans and Latinos at especially high risk.

Vitamin D is naturally present in few foods, and some researchers recommend supplements containing as many as 2,000 International Units (IU) of vitamin D for many people, and even more for those who are obese.

The current recommendations, however, are 200 to 600 units a day, depending on age.”

After reading this, I went to the research article itself, in order to get to the bottom of these new findings.

The study title (“Serum 25-Hydroxyvitamin D3 Levels Are Associated With Breslow Thickness at Presentation and Survival from Melanoma”) immediately tells us that it includes only patients who already have a diagnosis of melanoma.  It does not compare patients with a history or diagnosis of melanoma to patients without a history or diagnosis of melanoma in terms of their Vitamin D levels.  In other words, it is not meant to imply that increased levels of Vitamin D will prevent the average person from acquiring melanoma.

The authors’ hypothesis was that vitamin D could protect against the recurrence of melanoma. This was based on a pilot retrospective study, which means that they looked backwards in time for factors associated with a particular known outcome.  In this case, they compared a group of melanoma relapsers to a group of melanoma nonrelapsers (people who had a treated primary melanoma but did not receive a secondary diagnosis years after the fact) in terms of their Vitamin D levels, which were assessed by self-report questionnaires and a blood draw.  Their results indicated that nonrelapsers had higher Vitamin D levels than relapsers, although the results were not statistically significant.  Statistical significance is the barometer that is utilized in scientific studies to state the strength of a research finding.

In order to test their hypothesis, they went on to do a prospective cohort study, which is a study that waits for a particular outcome to occur, and then relates this outcome to the suspected associated factors.  872 participants who had a primary melanoma with a tumor thickness greater than 0.75 mm were identified.  These participants were followed after treatment for the primary melanoma and monitored over time to assess their vitamin D intake and status (again via self-report questionnaires and blood draws).  Throughout the course of the study, which lasted eight years, there were 173 relapses and 141 deaths.  They had a number of interesting findings, but the two most pertinent to what has been reported in the general media were:

1. Increased Breslow thickness (a measure of how deeply tumor cells have invaded) was, in fact, associated with lower serum vitamin D levels.  The article in Forbes stated that the associated melanomas were “less severe” and “less deadly” because thin melanomas have been shown to have a better prognosis.
2. Increases of 20 nmol/L in serum vitamin D levels were associated with a reduced risk of melanoma relapse as well as overall survival rate.

In their synopsis, the authors identify the limitations of their study and address what lies at the heart of the controversy surrounding their results: Melanoma patients are advised to stay out of the sun after diagnosis, with the thought that this will prevent recurrence.  In doing so, are they also endangering themselves by limiting their Vitamin D intake?  The authors do not believe so.  They state that although Vitamin D sufficiency should be encouraged, this can be done with Vitamin D supplements and a proper diet.

The bottom line?  No one is advocating that people should stop their methods of sun protection in order to acquire Vitamin D and prevent melanoma.  You can be sure that much more research will be invested into the intricate relationship between sun exposure, skin cancer, and Vitamin D in the near future.  For the time being, keep yourself protected from skin cancer with our sun safety guidelines, and avoid Vitamin D deficiency by taking a supplement and eating foods rich in Vitamin D.

REFERENCES:

Newton-Bishop JA et al. Serum 25-Hydroxyvitamin D3 levels are associated with Breslow thickness at presentation and survival from melanoma. J Clin Oncol, in press. Epub ahead of print retrieved on September 27, 2009 from http://jco.ascopubs.org/cgi/content/abstract/JCO.2009.22.1135v1.