Vitamin D status in adult patients with nonmelanoma skin cancer in Cape Town, South Africa: a cross-sectional study

Vitamin D and Skin Cancer: A Controversial Society. Literature Update and Review

Vitamin D (VD) deficiency has been associated with various tumors. However, the association between VD and skin cancer is controversial. Although in non-melanoma skin cancer, adequate or even high levels of VD can be associated with a higher risk of developing tumors, this could be biased by the direct association between sun exposure and VD levels. Regarding melanoma, results are contradictory. Most studies analyzed state that higher levels of VD could reduce the risk of melanoma, be associated with melanomas with better prognosis and with an enhanced antitumor response, and also with fewer adverse events associated with melanoma immunotherapy. However, prospective studies of adequate methodological quality are still needed to assess the association between VD levels and its supplementation and development/prognosis in skin cancer.

[Translated article] Vitamin D and Skin Cancer: A Controversial Society. Literature Update and Review

Vitamin D (VD) deficiency has been associated with various tumors. However, the association between VD and skin cancer is controversial. Although in non-melanoma skin cancer, adequate or even high levels of VD can be associated with a higher risk of developing tumors, this could be biased by the direct association between sun exposure and VD levels. Regarding melanoma, results are contradictory. Most studies analyzed state that higher levels of VD could reduce the risk of melanoma, be associated with melanomas with better prognosis and with an enhanced antitumor response, and also with fewer adverse events associated with melanoma immunotherapy. However, prospective studies of adequate methodological quality are still needed to assess the association between VD levels and its supplementation and development/prognosis in skin cancer.

Exposome and Skin. Part 2. The Influential Role of the Exposome, Beyond UVR, in Actinic Keratosis, Bowen's Disease and Squamous Cell Carcinoma: A Proposal

Actinic keratosis (AK) is the main risk factor for the development of cutaneous invasive squamous cell carcinoma (SCC). It represents the first sign of severe chronic ultraviolet radiation exposure, which has a clear significant effect. Nevertheless, the skin is exposed to many other exposome factors which should be thoroughly considered. Our aim was to assess the impact of exposome factors other than ultraviolet radiation (UVR) on the etiopathology of AK and Bowen's disease (BD) and progression of AK to SCC and to design tailored prevention strategies. We performed an exhaustive literature search in September 2021 through PubMed on the impact of exposome factors other than UVR on AK, BD and SCC. We conducted several parallel searches combining terms of the following topics: AK, BD, SCC and microbiome, hormones, nutrition, alcohol, tobacco, viral infections, chemical contaminants and air pollution. Notably, skin microbiome studies have shown how Staphylococcus aureus infections are associated with AK and AK-to-SCC progression by the production of chronic inflammation. Nutritional studies have demonstrated how a caloric restriction in fat intake, oral nicotinamide and moderate consumption of wine significantly reduce the number of premalignant keratoses and SCC. Regarding lifestyle factors, both alcohol and smoking are associated with the development of SCC in a dose-dependent manner. Relevant environmental factors are viral infections and chemical contaminants. Human papillomavirus infections induce deregulation of cellular proliferation and are associated with AK, BD and SCC. In addition to outdoor jobs, occupations such as industrial processing and farming also increase the risk of developing keratoses and SCC. The exposome of AK will undoubtedly help the understanding of its etiopathology and possible progression to SCC and will serve as a basis to design tailored prevention strategies.

Erythemal and vitamin D weighted solar UV dose-rates and doses estimated from measurements in mainland France and on Réunion Island

Solar UV radiation causes beneficial and detrimental changes in human health. International and national Health agencies recommend avoiding sun exposure when the solar rays are strongest (typically 2 h before and after solar noon). In this study we detail and refine such recommendations. We estimated biologically-effective radiation (inductive of erythema and pre-vitamin D) using spectral solar UV radiation measurements on a horizontal plane at three French sites equipped with spectroradiometers: Villeneuve d'Ascq (VDA) (North of France); Observatoire de Haute-Provence (OHP) (French Southern Alps); and Saint-Denis de La Réunion (SDR) on Réunion Island, in the Indian Ocean. These sites are very different: VDA is a semi-urban site in a flat region, OHP a rural mountainous site and SDR a coastal urban site on a small mountainous island. Biologically active radiation was analyzed by studying erythema induction and measuring pre-vitamin D synthesis. Dose-rates, doses and times for sunburn induction and vitamin D production were derived. Regarding the level of vitamin D dose considered here (1000 IU), we found that at mainland sites time required for vitamin D synthesis was relatively long, even around solar noon, in winter months this could be 2-3 h for phototype II individuals exposing their face and hands. In the tropics vitamin D could always be synthesized in a reasonable time (e.g. 20 min in winter). By contrast, in summer, the required duration times (exposing face, hands, arms and legs) are very short, approximately 2-4 min on the mainland and 1 min in the tropics for phototype II individuals. In all skin phototypes the duration of sun exposure required to induce erythema was generally longer than that to produce vitamin D. These quantitative results, obtained using an instrument measuring on a horizontal plane and with an unobstructed view, do not represent realistic values for human exposure. To account for realistic human body exposure, received doses and times of exposure were adjusted. Our study shows that, mostly in summer, the time periods where limited solar exposure is recommended should be extended, especially at low latitude locations.

Vitamin D serum levels and non-melanoma skin cancer risk

Background

Skin cancer is one of the common malignancies. There is sufficient evidence that sunlight (ultraviolet radiation) contributes to the development of skin cancer, but there is also evidence that relates adequate serum levels of vitamin D produced on the skin by the action of ultraviolet radiation with the decreased risk of various types of cancers, including skin cancer. The aim of this study was to investigate the association of vitamin D serum levels among patients with non-melanoma skin cancers (basal cell carcinoma and squamous cell carcinoma) and controls.

Methods

A prospective observational case-control study was conducted in a sample of 84 subjects in Extremadura (Spain). Forty-one patients with histologically diagnosed basal cell carcinomas and squamous cell carcinomas and 43 healthy controls were randomly chosen to assess whether vitamin D (25(OH)D₃) serum level, age and sex were related to non-melanoma skin cancer and to determine the possible risk of this type of skin cancer for these variables.

Results

When analysing serum vitamin D levels, we ensured that all our subjects, both cases and controls, had normal or low serum vitamin D levels, even though the samples were taken during months with the highest solar irradiance in our region. It is striking in our results that there was a higher percentage of subjects with deficits of vitamin D who did not have skin cancer (66%) than patients with deficits with these types of skin cancers (34%). When adjusting the model for age and sex, vitamin D values above 18 ng/ml increased the risk of suffering from non-melanoma skin cancer by nearly 7-fold (aOR: 6.94, 95% CI [1.55-31.11], p = 0.01).

Conclusions

Despite the controversial data obtained in the literature, our results suggest that lower levels of vitamin D may be related to a reduced incidence of non-melanoma skin cancer.

Assessment of sun-related behavior and serum vitamin D in basal cell carcinoma: Preliminary results

Ultraviolet radiation (UV), mainly from sunlight, is the main risk factor of the most common human skin cancer, basal cell carcinoma (BCC). A positive effect of UV on the skin is its contribution to the synthesis of vitamin D, which is important in sustaining general health, but having high levels of vitamin D is considered a risk factor for BCC. However, vitamin D receptor has antagonistic effects to UV radiation in regulating Sonic Hedgehog pathway. This is a pilot study aimed at characterizing the sun-related behavior and vitamin D status of 52 BCC patients and 59 controls from our geographical area. Patients were included in 4 subgroups: Single, multiple, recurrent, and both multiple and recurrent BCCs. Patients, more than controls, had at least one sunburn in childhood and lentigines (P<0.001). Also, they spent daily, on average, more time in the sun than controls (P<0.001) (3.00-8.00 and 1.50-4.00 h respectively). Outdoor work was similar in both groups. Participants had lower vitamin D serum levels than expected. Due to the small number of cases, no statistically significant differences were found between the subgroups but some tendencies were noted. Patients with only one recurrent BCC had less sunburns than the ones who also developed tumors at multiple sites (P=0.2). Patients with multiple and recurrent tumors had slightly lower vitamin D levels compared with single BCC patients (P=0.1) although they used more vitamin D supplements after the BCC diagnosis (P=0.2). Having a diagnosis of BCC, made patients more compliant to the use of sunscreen cream, but even so, half of them still did not use it. In conclusion, more effort should be invested in sun-related education and public health actions should focus on vitamin D deficiencies.