Department of Medical Oncology, Princess Margaret Hospital, Toronto, Ontario, Canada.
Cancer. 2010 Jan 15;116(2):284-91. doi: 10.1002/cncr.24749.
Vitamin D deficiency has potential roles in breast cancer etiology and progression. Vitamin D deficiency has also been associated with increased toxicity from bisphosphonate therapy. The optimal dose of vitamin D supplementation is unknown, but daily sunlight exposure can generate the equivalent of a 10,000-IU oral dose of vitamin D(3). This study therefore aimed to assess the effect of this dose of vitamin D(3) in patients with bone metastases from breast cancer.
Patients with bone metastases treated with bisphosphonates were enrolled into this single-arm phase 2 study. Patients received 10,000 IU of vitamin D(3) and 1000 mg of calcium supplementation each day for 4 months. The effect of this treatment on palliation, bone resorption markers, calcium metabolism, and toxicity were evaluated at baseline and monthly thereafter.
Forty patients were enrolled. No significant changes in bone resorption markers were seen. Despite no change in global pain scales, there was a significant reduction in the number of sites of pain. A small but statistically significant increase in serum calcium was seen, as was a significant decrease in serum parathyroid hormone. Treatment unmasked 2 cases of primary hyperparathyroidism, but was not associated with direct toxicity.
Daily doses of 10,000 IU vitamin D(3) for 4 months appear safe in patients without comorbid conditions causing hypersensitivity to vitamin D. Treatment reduced inappropriately elevated parathyroid hormone levels, presumably caused by long-term bisphosphonate use. There did not appear to be a significant palliative benefit nor any significant change in bone resorption.
维生素 D 缺乏症可能在乳腺癌的病因和发展中起作用。维生素 D 缺乏症也与双膦酸盐治疗的毒性增加有关。维生素 D 补充的最佳剂量尚不清楚，但每天晒太阳可以产生相当于口服 10000IU 维生素 D(3)的效果。因此，本研究旨在评估该剂量的维生素 D(3)对乳腺癌骨转移患者的影响。
本单臂 2 期研究纳入了接受双膦酸盐治疗的骨转移患者。患者每天接受 10000IU 维生素 D(3)和 1000mg 钙补充剂，持续 4 个月。在基线和此后每月评估该治疗对缓解、骨吸收标志物、钙代谢和毒性的影响。
共有 40 名患者入组。骨吸收标志物未见明显变化。尽管全球疼痛量表无明显变化，但疼痛部位的数量显著减少。血清钙略有但统计学上显著增加，甲状旁腺激素水平显著降低。治疗揭示了 2 例原发性甲状旁腺功能亢进症，但与直接毒性无关。
在没有引起维生素 D 过敏的合并症的患者中，每天服用 10000IU 维生素 D(3)持续 4 个月似乎是安全的。治疗降低了长期使用双膦酸盐引起的不适当升高的甲状旁腺激素水平。似乎没有明显的缓解作用，也没有明显的骨吸收变化。
