Background: Vitamin D deficiency has been known to be associated with the aggressiveness and prognosis of several cancers. This study evaluated the effect of preoperative serum vitamin D levels on the aggressiveness and prognosis of papillary thyroid cancer (PTC).
Methods: In total, 820 patients with PTC were enrolled. 25-hydroxyvitamin D levels were measured in blood samples before surgery. Clinical, pathologic, and recurrence data were accessed to examine the prognostic effects of vitamin D. Patients were categorized into four quartiles by preoperative serum vitamin D levels.
Results: Of the enrolled patients, 795 (97%) had insufficient vitamin D levels (<30 ng/mL). Vitamin D levels showed positive correlations with age and body mass index (BMI), and negative correlations with serum thyrotropin levels and antithyroid peroxidase antibody titers. The association between vitamin D quartile and the risks of extrathyroidal invasion, lymph node metastasis, advanced cancer stages (III or IV), and risk of recurrence were not significant after adjusting for age, sex, BMI, preoperative ionized calcium, and parathyroid hormone. Additionally, serum vitamin D was not associated with recurrent or persistent PTC.
Conclusion: Serum vitamin D levels are not associated with either disease aggressiveness or poor outcomes among patients with PTC and vitamin D insufficiency.