A Systematic Review Supporting the Endocrine Society Clinical Practice Guideline on the Treatment of Hypercalcemia of Malignancy in Adults

Context: Hypercalcemia is a common complication of malignancy that is associated with high morbidity and mortality. Objective: To support development of the Endocrine Society Clinical Practice Guideline for the treatment of hypercalcemia of malignancy in adults. Methods: We searched multiple databases for studies that addressed 8 clinical questions prioritized by a guideline panel from the Endocrine Society. Quantitative and qualitative synthesis was performed. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess certainty of evidence. Results: We reviewed 1949 citations, from which we included 21 studies. The risk of bias for most of the included studies was moderate. A higher proportion of patients who received bisphosphonate achieved resolution of hypercalcemia when compared to placebo. The incidence rate of adverse events was significantly higher in the bisphosphonate group. Comparing denosumab to bisphosphonate, there was no significant difference in the rate of patients who achieved resolution of hypercalcemia. Two-thirds of patients with refractory/recurrent hypercalcemia of malignancy who received denosumab following bisphosphonate therapy achieved resolution of hypercalcemia. Addition of calcitonin to bisphosphonate therapy did not affect the resolution of hypercalcemia, time to normocalcemia, or hypocalcemia. Only indirect evidence was available to address questions on the management of hypercalcemia in tumors associated with high calcitriol levels, refractory/recurrent hypercalcemia of malignancy following the use of bisphosphonates, and the use of calcimimetics in the treatment of hypercalcemia associated with parathyroid carcinoma. The certainty of the evidence to address all 8 clinical questions was low to very low. Conclusion: The evidence summarized in this systematic review addresses the benefits and harms of treatments of hypercalcemia of malignancy. Additional information about patients' values and preferences, and other important decisional and contextual factors is needed to facilitate the development of clinical recommendations.