Relationships between serum levels of vitamins and papillary thyroid cancer: a single center case-control study

Vitamins are involved in various human physiological and biochemical mechanisms due to their antioxidant properties and their ability to enhance the immune response. Deficiency of some serum vitamins has been reported to be associated with an increased risk of developing cancer, including thyroid cancer. However, medical literature dealing with cholecalciferol supplementation was not able to show the potential of this intervention in cancer prevention. The aim of this paper is to highlight the association between lower serum vitamins levels and papillary thyroid cancer occurrence.

This case-control study was conducted between September 2018 and October 2019. Cases were defined as patients with histologically diagnosed papillary thyroid cancer who underwent thyroidectomy were retrospectively recruited and serum levels of various vitamins were assessed by examining their relationships with clinical, pathological and molecular data (n=51). Controls matched on sex and thyroid surgery were randomly selected from the same population (n=49).

In this study, serum concentrations of vitamins A and E in neoplastic patients were significantly lower than in controls (1.40 vs. 1.78, P<0.003 and 23.9 vs. 29.1, P<0.003, respectively). Serum concentrations of vitamin D and methylmalonic acid were borderline significantly low (15.6 vs. 17.9, P=0.06 and 100.3 vs. 110.4, P=0.055, respectively), while homocysteine was statistically similar in the two groups. Furthermore, serum vitamin levels were compared with the pathological characteristics of cancer patients, and vitamin D concentrations were significantly lower in BRAF-positive than in BRAF-negative neoplastic patients (8.2 vs. 16.0, P=0.021). On the other hand, no significant differences were observed in the correlation between serum levels of vitamins and other pathological characteristics, in particular with regard to lymph node metastases.

In conclusion, albeit with the analysis of a limited sample, this study highlighted the phenomenon that deficiencies in vitamins A and E can be associated with a higher frequency of occurrence of papillary thyroid cancer.