RESUMO
ABSTRACT Objective: This study was conducted to assess the serum 25-hydroxy (OH) vitamin D levels in patients with breast cancer compared to healthy controls and to identify its association with aggressive breast cancer phenotypes. Materials and methods: Serum 25-OH vitamin D levels of 78 breast cancer patients and 78 matched healthy controls were estimated using ELISA. The cases and controls were matched with respect to age, menopausal status, parity, weight, height and co-morbidities. Prognostic factors like grade of tumour, hormone receptor status, HER2 neu status and lymphovascular invasion were compared with 25-OH vitamin D levels. Results: The mean serum 25-OH vitamin D levels of cases were significantly lower compared to the controls (22.33 ± 8.19 vs. 37.41 ± 12.9 ng/mL; p = 0.0001). Patients with higher grades of tumour, non-luminal types of breast cancer and breast cancers with estrogen receptor negativity had significantly lower serum 25-OH vitamin D levels than their opposing groups. Patients with excellent and good Nottingham's prognostic Index (NPI) had significantly higher serum 25-OH vitamin D levels than the moderate and poor NPI groups. Conclusion: Newly diagnosed breast cancer patients have significantly lower serum 25-OH vitamin D levels than healthy controls. Lower level of serum 25-OH vitamin D correlates with aggressive breast cancer phenotypes.