Prostaglandin synthesis inhibitors
Prostaglandin synthesis inhibitors such as the nonsteroidal anti-inflammatory drugs may have some efficacy in the management of cancer-induced hypercalcemia. The E-series prostaglandins mediate bone resorption. Despite experimental evidence, however, aspirin and other nonsteroidal drugs have demonstrated only modest clinical response rates in controlling hypercalcemia. For patients who are unresponsive to or unable to tolerate other agents, aspirin may be given to produce a serum salicylate concentration equal to 20 to 30 mg/dL, or 25 mg indomethacin may be given orally every 6 hours.[53,54,55][Level of evidence: II];[Level of evidence: III]
Serum calcium was normalized for a median of 34 days (range, 4–115) in 9 of 13 patients with various solid tumors given IV cisplatin at 100 mg/m2 of body surface area over 24 hours. Patients were re-treated as frequently as every 7 days if necessary to maintain serum calcium concentrations lower than 11.5 mg/dL (<5.75 mEq/L or 2.87 mmol/L). Four of seven patients responded to repeated treatment. Responders achieved a statistically significant difference in serum calcium levels from baseline on the tenth day after treatment, which continued thereafter. Serial tumor measurements revealed that the hypocalcemic response did not correlate with tumor shrinkage; there was no detectable antitumor response in any measurable or evaluable disease.
Future pharmacologic management is likely to combine osteoclastic inhibitors with cytotoxic or endocrine therapy.
Patient and Family Education
Hypercalcemia compromises the patient's quality of life and can be life-threatening if not promptly recognized and treated. Individuals at risk and their caregivers should be made aware that hypercalcemia is a possible complication. Patients and their significant others should be advised about the types of symptoms that may occur with hypercalcemia, preventive measures, exacerbating factors, and when to seek medical assistance. They should be taught measures to diminish the symptoms of hypercalcemia such as maintaining mobility and ensuring adequate hydration.
Despite encouraging developments in pharmacologic management, the prognostic implications related to hypercalcemia remain relatively grim. Only patients for whom effective anticancer therapy is possible can be expected to experience a longer survival.
The adverse effects of therapy need to be prevented or recognized and managed. Fluid overload and electrolyte imbalance can occur during initial therapy. Serum sodium, potassium, calcium, phosphate, and magnesium concentrations may be markedly decreased. Electrolyte levels should be monitored at least daily, and clinical signs and symptoms should be assessed at least every 4 hours when hydration or specific hypocalcemic drug treatments are being implemented.
The management of symptoms of hypercalcemia is crucial. Preventing accidental or self-inflicted injury as a consequence of the patient's altered mental status is a priority during acute management. Until serum calcium decreases, additional pharmacologic interventions may be necessary to control nausea, vomiting, and constipation.