Z. L. Gentry2, E. Pruitt3, J. K. Kirklin3,4, C. Contreras1, T. Wang1 1University Of Alabama at Birmingham,Division Of Surgical Oncology,Birmingham, Alabama, USA 2University Of Alabama at Birmingham,School Of Medicine,Birmingham, Alabama, USA 3University Of Alabama at Birmingham,Kirklin Institute For Research In Surgical Outcomes,Birmingham, Alabama, USA 4University Of Alabama at Birmingham,Division Of Cardiothoracic Surgery,Birmingham, Alabama, USA
Introduction: The cumulative effect of sun exposure on melanoma risk is highly complex and difficult to predict. Although intermittent sun exposure sufficient to cause burning is a major risk factor for the development of melanoma, regular sun exposure may be protective due to the consequent higher levels of vitamin D. Multiple studies have confirmed that vitamin D induces growth arrest, triggers cell death and promotes differentiation of cancer cells. Higher levels of vitamin D correlate with better survival of patients with breast, colon, and prostate cancer. We hypothesize that melanoma patients with lower vitamin D levels exhibit more advanced stage disease than patients with normal vitamin D levels.
Methods: A database of 497 patients from a single institution treated for melanoma from 2010-2017 was retrospectively reviewed. Serum 25-hydroxyvitamin D levels were measured in 129 patients at a time near their diagnosis. Patients were categorized as Low VD if their 25-hydroxyvitamin D levels were <30 ng/ml and Normal VD if their 25-hydroxyvitamin D levels were >30 ng/ml. Patient vitamin D assessment categories were then compared to their melanoma stage at diagnosis. Each patient’s melanoma was categorized as Early Stage or Late Stage based on their AJCC classification. Early Stage was defined as local disease (stages 0, I, II). Late Stage was defined as lymph node and distant metastatic disease (stages III and IV). Chi-squared analysis was used to determine the association between the categorical variables. Medians with interquartile ranges were calculated for vitamin D levels and compared by Wilcoxon rank sum test.
Results: There were 63 Low VD patients and 66 Normal VD patients. Low VD patients were more likely to present with Late Stage disease than Normal VD patients (27.0% vs. 10.6%, p=0.02). The median 25-hydroxyvitamin D level of Early Stage melanoma patients was significantly higher than Late Stage melanoma patients (30.1 and 25.4 ng/ml, respectively; p=0.02).
Conclusion: Melanoma patients deficient in vitamin D exhibit more advanced disease when compared to melanoma patients with normal vitamin D levels. Sun exposure may confer a protective advantage against melanoma by increasing levels of vitamin D necessary for inhibiting cancer progression. Further research to elucidate the inhibitory effects of vitamin D in carcinogenesis will provide more effective means of prevention and treatment of melanoma.