Prevalence of hypercalcemia of malignancy among pediatric cancer patients in the UK Clinical Practice Research Datalink database

BACKGROUND The reported proportion of cancer patients who experience hypercalcemia of malignancy (HCM) is low, particularly in the pediatric population, ranging between <1% and 5%. HCM can be observed with any type of tumor in children and occurs most commonly with leukemia. While HCM is a potentially fatal condition, the prevalence of HCM is not well understood in pediatric cancer patients. METHODS Using the UK Clinical Practice Research Datalink, we identified pediatric cancer patients with recorded corrected serum calcium (CSC) from 2003 through 2014. Hypercalcemic patients (CSC ≥10.8 mg/dL) were classified into 4 CSC levels. We estimated the annual prevalence of HCM using Byar's method. RESULTS Among 517 pediatric cancer patients, leukemia, lymphoma, and brain tumors were the most frequent cancer types. The prevalence of HCM overall (grade 1 or higher) ranged from 0.24% to 0.81% between 2003 and 2014. There were too few cases to compare prevalence by type of cancer. CONCLUSION We provide the first systematic analysis using a UK population-based data source to estimate the number of pediatric cancer patients affected with HCM by grade. Our findings showed that the prevalence of pediatric HCM was very low (0.24%-0.81%) over the 12-year study period, which is consistent with previous study of adult cancer patients in the UK (0.20%-0.67%).