High serum 25-hydroxyvitamin D concentration in patients with a recent diagnosis of non-melanoma skin cancer: a case-control study.

Background: Sun exposure is critical for vitamin D synthesis and is a major risk factor for the development of non-melanoma skin cancer (NMSC). NMSC is the most common type of cancer in Brazil and coexists with a very high prevalence of vitamin D deficiency.

Objectives: The present study aimed to assess serum 25-hydroxyvitamin D (25[OH]D) concentration in patients with a recent diagnosis of NMSC.

Materials & Methods: The serum 25(OH)D concentration of patients with a histological diagnosis of NMSC, made between September 2016 and September 2017, was measured by chemiluminescence up to 60 days after diagnosis and compared to healthy individuals without NMSC matched by age, sex, BMI, and skin phototype.

Results: Forty-one patients with NMSC and 200 healthy controls were evaluated. Most of the patients were men (56.1%) and most had basal cell carcinoma (90.2%). Patients were 67 years old on average (21-87 years) with skin Phototype 2 or 3 (80.6%). Mean serum 25(OH)D concentration in NMSC patients was significantly higher than in healthy controls (p < 0.001). Most of the patients with NMSC (65.9%) had vitamin D deficiency (25[OH]D <30 ng/mL). No association was identified between histological type, time from diagnosis, or a previous history of skin neoplasm and 25(OH)D measurements.

Conclusion: Patients with recently diagnosed NMSC had significantly higher serum levels of 25(OH)D when compared to healthy controls. On the other hand, most of the NMSC patients were still considered to have vitamin D insufficiency.