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Vitamin D deficiency is associated with greater tumor thickness in melanoma patients

Posted on: May 22, 2015   by  Missy Sturges & John Canell, MD


A recent study in Brisbane Australia found an association between vitamin D deficiency and tumor thickness in newly diagnosed melanoma patients.

Melanoma is the most lethal form of skin cancer, accounting for over 55,000 deaths annually. It is also the 10th most common form of cancer in highly developed regions.

The relationship between sun exposure and melanoma is complex. Ultraviolet radiation, especially sunburns, is widely understood to be a risk factor for the development of melanoma in fair skinned individuals. However, some research has shown vitamin D and sun exposure may have positive effects on the prognosis of melanoma.

Tumor thickness is associated with cancer prognosis, meaning patients with thicker tumors tend to have a poorer prognosis. Vitamin D has shown to minimize tumor growth through prevention of cellular proliferation, as well as promotion of programmed cell death of diseased cells.

In this study, researchers wanted to see if vitamin D status is linked to melanoma thickness at the time of cancer diagnosis.

The researchers enrolled 100 melanoma participants around the time of initial diagnosis. They provided a questionnaire and physical examination in order to determine previous melanoma risk and prognosis. They evaluated the participant’s history of sun exposure, childhood sunburns and solar elastosis, which is a condition that involves degeneration of the collagen in the skin due to excessive sun exposure.

Tumor thickness was measured via Breslow’s Thickness, a tool used to determine the distance between the upper layer of the epidermis and the deepest point of the tumor. They also obtained serum 25(OH)D levels at the time of excisional biopsy, which is a procedure that tries to remove all of the cancerous tissue at the time of the first surgery (biopsy).

Here is what the researchers found:

  • Over one-third of the participants had serum vitamin D levels less than 20 ng/ml.
  • Individuals with serum vitamin D levels less than 20 ng/mL were associated with almost 4 times the odds (OR = 3.82) of having a thicker tumor (p = 0.04).
  • Participants with vitamin D levels less than 18ng/mL had 5 times the chances (OR = 5.03) of having a thicker tumor (p = 0.02)
  • There was no significant relationship between vitamin D status and other histological indicators of prognosis
  • There was also no significant association between sun exposure, history of childhood sunburns or solar elastosis and markers of prognosis.

The researchers concluded,

“Vitamin D deficiency at the time of melanoma diagnosis is associated with thicker tumors that are likely to have a poorer prognosis.”

They went on to state,

“Maintaining a vitamin D level of at least 20ng/mL is advisable as our results indicate that vitamin D deficiency is associated with thicker melanomas, which have, separately, been shown to have poorer prognosis.”

There were a couple of strengths to note regarding this study. The sample size represents approximately 9% of the melanomas diagnosed annually in the Brisbane area, making the study more likely to be representative of the population. Also, since vitamin D levels were measured near the time of diagnosis, participants did not yet begin making lifestyle changes that could skew the findings. For example, previous studies have found an association between vitamin D levels and melanoma prognosis, but critics pointed out this may be due to melanoma patients avoiding the sun. This study disproved those critics.

The researchers also pointed out some limitations. Since the study was cross sectional, there is no data on the actual outcomes of these patients. Also, the study doesn’t prove causation.

Randomized controlled trials are needed to evaluate the effects of vitamin D supplementation on melanoma prognosis. This paper adds to the hundreds of reasons why individuals should not allow themselves to be vitamin D deficient.


Wyatt, C., et al. Vitamin D Deficiency at Melanoma Diagnosis is Associated with Higher Breslow Thickness. PloS one, 2015

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