Prevalence and clinical significance of hypercalcemia at diagnosis in diffuse large B-cell lymphoma

The reported prevalence of hypercalcemia at diagnosis in non-Hodgkin-lymphoma ranges between 1.3% and 7.4%. These studies included all patients, regardless of lymphoma subtype. We performed a retrospective case-control study to determine the prevalence of hypercalcemia at time of diagnosis in patients with diffuse large B-cell lymphoma (DLBCL). Among 250 newly diagnosed patients, 46 (18%) had hypercalcemia. When compared with age-sex matched patients and normal calcium levels, those with hypercalcemia had higher levels of LDH, lower levels of albumin and more advanced stage. These differences were translated to shorter progression-free-survival and overall survival, but only in patients with hypercalcemia and low levels of parathyroid hormone (PTH). These findings suggest that in newly diagnosed patients with DLBCL, hypercalcemia is more frequent than previously appreciated. Furthermore, lymphoma-related but not primary hyperparathyroidism-related hypercalcemia is associated with adverse prognostic factors and adverse clinical outcomes in DLBCL. Hence, PTH should be obtained in patients with DLBCL and hypercalcemia at diagnosis.