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Hypercalcemia Is of Uncertain Significance in Patients With Advanced Adenocarcinoma of the Prostate

Hypercalcemia in the setting of prostate cancer is rare with an uncertain pathophysiology and more research is needed into the role of parathyroid hormone-related peptide as a growth factor and possibly target-directed monoclonal antibody therapies.
Federal Practitioner. 2020 July;37(7)a:320-324
July 9, 2020|Federal Practitioner
Ghaith Alhatemi, MD;Rafal Alhatemi, MD;Haider Aldiwani, MD;Marwah Hussein, MD;Edi Levi, MD;Pallavi Jasti, MD
Author and Disclosure Information

Ghaith Alhatemi and Marwah Hussein are Internists and Rafal Alhatemi is a Research Assistant, all at the Detroit Medical Center, Wayne State University in Michigan. Haider Aldiwani is an Internist at Scripps Mercy Hospital Chula Vista in San Diego, California. Edi Levi is a Pathologist and Pallavi Jasti is a Medical Oncologist, both at John Dingell VA Medical Center in Detroit. Correspondence: Ghaith Alhatemi (galhatem@med.wayne.edu

Author Disclosures
The authors report no actual or potential conflicts of interest with regard to this article.

Disclaimer
The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the US Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review the complete prescribing information for specific drugs or drug combinations— including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.

Hypercalcemia is found when the corrected serum calcium level is > 10.5 mg/dL.1 Its symptoms are not specific and may include polyuria, dehydration, polydipsia, anorexia, nausea and/or vomiting, constipation, and other central nervous system manifestations, including confusion, delirium, cognitive impairment, muscle weakness, psychotic symptoms, and even coma.1,2

Hypercalcemia has varied etiologies; however, malignancy-induced hypercalcemia is one of the most common causes. In the US, the most common causes of malignancy-induced hypercalcemia are primary tumors of the lung or breast, multiple myeloma (MM), squamous cell carcinoma of the head or neck, renal cancer, and ovarian cancer.1

Men with prostate cancer and bone metastasis have relatively worse prognosis than do patient with no metastasis.3 In a recent meta-analysis of patients with bone-involved castration-resistant prostate cancer, the median survival was 21 months.3

Hypercalcemia is a rare manifestation of prostate cancer. In a retrospective study conducted between 2009 and 2013 using the Oncology Services Comprehensive Electronic Records (OSCER) warehouse of electronic health records (EHR), the rates of malignancy-induced hypercalcemia were the lowest among patients with prostate cancer, ranging from 1.4 to 2.1%.1

We present this case to discuss different pathophysiologic mechanisms leading to hypercalcemia in a patient with prostate cancer with bone metastasis and to study the role of humoral and growth factors in the pathogenesis of the disease.

Case Presentation

An African American man aged 69 years presented to the emergency department (ED) with generalized weakness, fatigue, and lower extremities muscle weakness. He reported a 40-lb weight loss over the past 3 months, intermittent lower back pain, and a 50 pack-year smoking history. A physical examination suggested clinical signs of dehydration.

Laboratory test results indicated hypercalcemia, macrocytic anemia, and thrombocytopenia: calcium 15.8 mg/dL, serum albumin 4.1 mg/dL, alkaline phosphatase 139 μ/L, blood urea nitrogen 55 mg/dL, creatinine 3.4 mg/dL (baseline 1.4-1.5 mg/dL), hemoglobin 8 g/dL, mean corpuscular volume 99.6 fL, and platelets 100,000/μL. The patient was admitted for hypercalcemia. His intact parathyroid hormone (iPTH) was suppressed at 16 pg/mL, phosphorous was 3.8 mg/dL, parathyroid hormone-related peptide (PTHrP) was < 0.74 pmol/L, vitamin D (25 hydroxy cholecalciferol) was mildly decreased at 17.2 ng/mL, and 1,25 dihydroxy cholecalciferol (calcitriol) was < 5.0 (normal range 20-79.3 pg/mL).

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