This study aims at assessing the vitamin Dstatus in breast cancer patients who receive letrozole for more than two months and to evaluate effects of vitamin D3 and calcium supplementation on arthalgia caused by letrozole on these patients.

Background: Vitamin D deficiency (< 10 ng/mL) and insufficiency (10-30 ng/mL) may contribute to musculoskeletal symptoms observed in patients taking letrozole. This study was undertaken to assess the vitamin D status in breast cancer patients who received letrozole for > 6 months and to evaluate the effects of vitamin D3 and calcium supplementation on them.

Methods: Forty breast cancer patients were included. They were divided into 2 equal groups: Control group received Letrozole only, and VitD/Ca group received Letrozole in addition to 2000 IU vitamin D3 and 1000 mg of calcium per day for 12 weeks. Baseline serum 25-hydroxy vitamin D concentrations were assayed and standard health assessment questionnaire was completed to assess the disability caused by musculoskeletal symptoms.

Inclusion Criteria:

• Newly diagnosed breast cancer patients.
• Postmenopausal hormone receptor positive.
• Patients receiving letrozole for more than two months
• Gender: Female.
• Age: ≥ 50 years old.

Exclusion Criteria:

• Patients with bone metastasis.
• History of renal stones.
• Serum calcium >11mg/L.
• Patients with renal insufficiency.
• Patients taking steroid hormone replacement therapy.
• Second Malignancy.