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.