Adequate levels of vitamin D are important for optimal bone health. Australian woman with early breast cancer are frequently vitamin D deficient and are exposed to additional risk factors for osteoporosis.
To gauge the burden of vitamin D deficiency, this study was designed to assess serum 25(OH)-D levels at two time-points: at commencement and completion of adjuvant systemic chemotherapy.
Serum 25(OH)-D levels were measured in patients over 2 time periods: 2009-2011 (cohort 1) and 2012-2016 (cohort 2).
Cohort 1 included 253 women and assessed 25(OH)-D levels at chemotherapy completion. Changes in serum 25(OH)-D levels were followed in a subgroup of patients (N= 63, subgroup A) at three and at twelve months.
Cohort 2 included 267 patients and assessed 25(OH)-D levels during chemotherapy. Baseline 25(OH)-D levels were measured within weeks of surgery, and a subgroup (N=102, subgroup B) agreed to check levels at chemotherapy completion and three months later.
In cohort 1, 53% (of 253 women) were vitamin D deficient (< 50 nmol/L) after systemic chemotherapy, and in cohort 2, 44% (of 267) had deficient serum 25OH-D levels prior to chemotherapy. In the majority, the deficiency was mild.
In subgroup A, there was a considerable improvement in serum 25(OH)-D levels, from 63% deficient (
In subgroup B, all 102 women had normal vitamin D levels prior to chemotherapy (>50 nmol/L). After chemotherapy, 51% had become deficient, but following replacement, only 6% were deficient 3 months later.
Vitamin D deficiency is common in Australian women with early breast cancer. Assessment and replacement of vitamin D should become part of routine management in this population.