Year: 2026 | Month: July | Volume: 13 | Issue: 7 | Pages: 175-182
DOI: https://doi.org/10.52403/ijrr.20260721
Low Vitamin D Receptor Expression and Low Vitamin D Levels as Risk Factors for Bone Metastasis in Stage III-IV Breast Cancer Patients
Hendra Aryudi Hamzah1, I Gede Eka Wiratnaya1, Lanang N. A. Artha Wiguna1, I Wayan Juli Sumadi1
1Department of Orthopaedic and Traumatology, Faculty of Medicine, Udayana University/Ngoerah Hospital, Denpasar, Indonesia
Corresponding Author: Hendra Aryudi Hamzah
ABSTRACT
Bone metastasis is one of the most frequent complications in advanced breast cancer and contributes substantially to morbidity. Vitamin D and the Vitamin D Receptor (VDR) are thought to play a role in bone metastasis by regulating tumor cell proliferation, differentiation, apoptosis, and bone homeostasis. This study aimed to analyze the association of VDR expression and low vitamin D levels with bone metastasis in patients with stage III-IV breast cancer. A case-control study was conducted involving 38 breast cancer patients at Prof. Dr. I.G.N.G. Ngoerah General Hospital, Denpasar, consisting of 19 patients with bone metastasis and 19 without bone metastasis. VDR expression was assessed in tumor tissue by immunohistochemistry using the Immunoreactive Score, while ELISA measured serum vitamin D levels. Statistical analysis included bivariate tests and multivariable logistic regression. Low VDR expression was found in 10.5% of cases and 5.3% of controls, with no significant association with bone metastasis (OR 2.118; p=1.000). In contrast, vitamin D levels <20 ng/mL were more common in the case group than in the control group, 57.9% versus 21.1%, and were significantly associated with bone metastasis (OR 5.156; 95%CI 1.234-21.554; p=0.045). In multivariable analysis, vitamin D levels <20 ng/mL remained independently associated with bone metastasis (aOR 13.629; 95%CI 1.826-101.729; p=0.011). In conclusion, low vitamin D levels were associated with bone metastasis, whereas VDR expression was not significantly associated.
Keywords: breast cancer, bone metastasis, vitamin D, Vitamin D Receptor, VDR
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