1,25-Dihydroxyvitamin D-related hypercalcemia in lymphoma: two case reports

Treatment of Hypercalcemia of Malignancy in Adults: An Endocrine Society Clinical Practice Guideline

BACKGROUND

Hypercalcemia of malignancy (HCM) is the most common metabolic complication of malignancies, but its incidence may be declining due to potent chemotherapeutic agents. The high mortality associated with HCM has declined markedly due to the introduction of increasingly effective chemotherapeutic drugs. Despite the widespread availability of efficacious medications to treat HCM, evidence-based recommendations to manage this debilitating condition are lacking.

OBJECTIVE

To develop guidelines for the treatment of adults with HCM.

METHODS

A multidisciplinary panel of clinical experts, together with experts in systematic literature review, identified and prioritized 8 clinical questions related to the treatment of HCM in adult patients. The systematic reviews (SRs) queried electronic databases for studies relevant to the selected questions. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make recommendations. An independent SR was conducted in parallel to assess patients' and physicians' values and preferences, costs, resources needed, acceptability, feasibility, equity, and other domains relevant to the Evidence-to-Decision framework as well as to enable judgements and recommendations.

RESULTS

The panel recommends (strong recommendation) in adults with HCM treatment with denosumab (Dmab) or an intravenous (IV) bisphosphonate (BP). The following recommendations were based on low certainty of the evidence. The panel suggests (conditional recommendation) (1) in adults with HCM, the use of Dmab rather than an IV BP; (2) in adults with severe HCM, a combination of calcitonin and an IV BP or Dmab therapy as initial treatment; and (3) in adults with refractory/recurrent HCM despite treatment with BP, the use of Dmab. The panel suggests (conditional recommendation) the addition of an IV BP or Dmab in adult patients with hypercalcemia due to tumors associated with high calcitriol levels who are already receiving glucocorticoid therapy but continue to have severe or symptomatic HCM. The panel suggests (conditional recommendation) in adult patients with hypercalcemia due to parathyroid carcinoma, treatment with either a calcimimetic or an antiresorptive (IV BP or Dmab). The panel judges the treatments as probably accessible and feasible for most recommendations but noted variability in costs, resources required, and their impact on equity.

CONCLUSIONS

The panel's recommendations are based on currently available evidence considering the most important outcomes in HCM to patients and key stakeholders. Treatment of the primary malignancy is instrumental for controlling hypercalcemia and preventing its recurrence. The recommendations provide a framework for the medical management of adults with HCM and incorporate important decisional and contextual factors. The guidelines underscore current knowledge gaps that can be used to establish future research agendas.

[Humoral hypercalcemia revealing a malignant non hodgkin lymphoma]

INTRODUCTION

Hypercalcemia is a rare complication of non-Hodgkin lymphoma. Usually, hypercalcemia occurs late in the disease course, except for high-grade lymphoma. Most often hypercalcemia is related to excessive level of circulating PTH-rP or sometimes, 1,25(OH)2D3. Concomitant high plasmatic concentration of PTH-rP and 1,25(OH)2D3 is uncommon.

EXEGESIS

We report the case of a 82-year-old man who presented with abdominal pain and weight loss, leading to the diagnosis of diffuse large-B-cell lymphoma (high-grade lymphoma) associated with symptomatic hypercalcemia (3.21mmol/l). PTH-rP and 1,25(OH)2D3 plasmatic levels were high. Calcium concentration was normalized with glucocorticoids and sequential chemotherapy.

CONCLUSION

This case report confirms that hypercalcemia, as consequence of excessive plasmatic level of PTH-rP secreted by tumoral cells, can occur early in the course of high-grade lymphoma. Glucocorticoids and chemotherapy are the best treatment options.