A 58-year-old woman undergoing systemic chemotherapy for advanced breast cancer with metastases to bone comes to the office for routine follow-up. She has mild, vague bone pain that is relieved by the occasional use of acetaminophen. Physical examination shows a well-healed mastectomy scar on the right and a palpable right supraclavicular lymph node. Mucous membranes are moist. Laboratory results are as follows:
Serum chemistry Sodium 144 mEq/L Potassium 3.8 mEq/L Chloride 102 mEq/L Bicarbonate 24 mEq/L Blood urea nitrogen 14 mg/dL Creatinine 0.8 mg/dL Calcium 11.4 mg/dL Glucose 146 mg/dL Liver function studies Albumin 3.4 g/dL
Which of the following is the best next step in management of this patient?
This patient presents with mild hypercalcemia in the setting of metastatic breast cancer to bone. Asymptomatic or mild hypercalcemia (calcium <12 mg/dL) does not require urgent therapy, but hypercalcemia of malignancy may worsen over time. Bisphosphonates (eg, zoledronic acid) inhibit the osteoclastic activity of bone, stabilizing destructive bony tumors and reducing the risk of skeletal-related events such as pathologic fracture and malignant hypercalcemia.
(Choice B) Corticosteroids are useful for hypercalcemia related to granulomatous disease as they reduce calcitriol release from activated mononuclear cells. However, they are not effective in hypercalcemia of malignancy, which operates via different mechanisms.
(Choice C) Loop diuretics can be used in patients who have moderate or severe hypercalcemia with volume overload from heart failure or renal insufficiency, but these drugs are not recommended for routine use otherwise.
(Choice D) Opioids are the first-line treatment for metastatic bone pain that is not adequately controlled by acetaminophen or nonsteroidal anti-inflammatory drugs. This patient is currently achieving adequate pain relief with acetaminophen; therefore, additional pain control is unnecessary.
(Choice E) Radiation therapy can treat moderate to severe pain caused by bone metastases. However, it would not be indicated at this time because this patient only has mild pain.
Educational objective:
Bisphosphonates (eg, zoledronic acid, pamidronate) are the drugs of choice for stabilizing bony metastatic lesions to prevent hypercalcemia of malignancy and pathologic fractures.