Decreased overall survival in melanoma patients with low vitamin D

A Spanish study found an independent association of vitamin D deficiency and worse overall survival in patients who were diagnosed with melanoma. This relationship remained when possible confounders like age, gender, season of vitamin measurement, and Breslow index were included in the analysis.

Is there a relationship between vitamin D levels and the prognosis of melanoma patients? This was the question that Dr Inés Gracia-Darder (Son Espases University Hospital, Spain) and her colleagues strove to answer in a retrospective cohort study [1,2]. The 264 investigated patients were treated between 1998 and 2021 for invasive melanoma in the Hospital Clinic in Barcelona and had their 25-hydroxyvitamin D3 levels determined after diagnosis. The study participants were assigned to 1 of 2 groups: those with a vitamin D level <10 ng/mL deemed ‘vitamin D deficient’ and those with levels ≥10 ng/mL, who were referred to as ‘normal/insufficient’. Not only the potential association of overall survival but also the melanoma-specific survival with the plasma levels of vitamin D were analysed.

The baseline characteristics were not significantly different between the study groups. The median age was 57.5 years, 54.2% of participants were women, and the majority had a skin phototype 2 or 3‒4. Regarding the melanoma specifics, 63.8% had a superficial spreading subtype, median Breslow index was 1.50 mm, and most tumours were situated on trunk and extremities (45.7% and 34.5%). In more than half of the participants, vitamin D had been measured between October and March.

The results established a reduced overall survival for participants who were vitamin D deficient in the univariate data assessment with an HR of 2.34 (P=0.007). This finding was corroborated in the following multivariate regression that adjusted for possible confounders like age, gender, season of vitamin measurement, and Breslow index (HR 2.45; P=0.007). Interestingly, having a deficiency in vitamin D did not lead to a decreased melanoma-specific survival in both the univariate and the multivariate analysis (P=0.511 and P=0.629). “Previous research has identified that normal levels of vitamin D play a protective role in melanoma survival, and this study aimed to further understand this relationship. Our findings suggest that vitamin D has a significant impact on people with melanoma, showing in particular that vitamin D deficient patients have a lower overall survival, independent of several confounders” Dr Gracia-Darder commented.

Considering these results, more insights are desirable to establish the definite role of vitamin D deficiency in melanoma. The currently active, Belgian, phase 3 ViDMe trial (NCT01748448) that investigates the influence of vitamin D supplementation on malignant melanoma after surgical removal of the primary tumour could shed more light on this matter.

1. Garcia-Darder I, et al. Worse overall survival associated with vitamin D deficiency in melanoma patients. P0762, EADV Congress 2022, Milan, Italy, 7–10 September.
2. Garcia-Darder I, et al. Melanoma Res. 2022;32(5):384‒387.

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Posted on 5 November, 20228 February, 2024