Background Hypercalcaemia of malignancy affects up to 30% of patients with cancer.¹ Treatment involves medications that inhibit bone resorption of calcium, such as bisphosphonates. Low vitamin D can cause refractory hypocalcaemia following these medications, therefore levels should be checked prior to their use and replaced if required. Vitamin D loading regimes often include a loading period of 6–8 weeks which is not always appropriate in palliative care patients, where median survival from onset of hypercalcaemia is 35 to 52 days.^{2 3}

Methods Two retrospective audits looked at palliative care unit in-patients prescribed medications for hypercalcaemia of malignancy in two NHS Foundation Trusts, both over a 12-month period. Data were collected on treatment given, whether vitamin D level were checked and vitamin D replacement.

Results There were 27 episodes of hypercalcaemia of malignancy treated with medication across the two palliative care units over a 12-month period. 23 episodes were treated with zolendronate, 3 with pamidronate and 1 with denosumab. Vitamin D level was checked prior to medication administration in 9 episodes (33%). Out of the 9 patients who had vitamin D levels checked, 6 had low vitamin D levels and 2 were treated with vitamin D replacement. One patient treated for vitamin D deficiency was given a one daily higher loading dose for 7 weeks followed by a maintenance dose and the other patient was started on a twice weekly regime.

Conclusions There was poor compliance with guidance to check vitamin D levels in patients with hypercalcaemia of malignancy. Where vitamin D levels were found to be low they were only replaced in 2 out of 9 episodes. A guideline has been produced to support more rapid Vitamin D replacement for patients with limited life-expectancy who are receiving treatment for hypercalcaemia of malignancy.

References

1. Stewart AF. Clinical practice. Hypercalcaemia Associated with Cancer. NEJM 2005;352(4):373–379.

2. Jin J, Chung JO, Chung MY, Cho DH, Chung DJ. Clinical characteristics, causes and survival in 115 cancer patients with parathyroid hormone related protein-mediated hypercalcaemia. J Bone Metab. 2017;24(4):249–255.

3. Donovan PJ, Achong N, Griffin K, Galligan J, Pretorius CJ, McLeod DD. PTHrP-mediated hypercalcaemia: causes and survival in 138 patients. J Clin Endocrinol Metab. 2015;100(5):2024–2029.