Hypercalcemia and cancer: Differential diagnosis and treatment

Incidentally detected hypercalcemia usually presents in an indolent manner and is most likely caused by primary hyperparathyroidism. In contrast, hypercalcemia in the patient with a history of cancer presents in a wide range of clinical settings and may be severe enough to warrant hospitalization. This form of hypercalcemia is usually secondary to hypercalcemia of malignancy and can be fatal. Hypercalcemia of malignancy is most commonly mediated by tumoral production of parathyroid hormone-related protein or by cytokines activating osteoclast degradation of bone. The initial workup, differential diagnoses, confirmatory laboratory testing, imaging, and medical and surgical management of hypercalcemia are described in the patient with cancer.

Risk of skeletal-related events in patients with advanced prostate cancer treated with pamidronate or zoledronic acid

BACKGROUND

Pamidronate and zoledronic acid are used for the prevention of skeletal-related events (SREs) in patients with advanced solid tumors, particularly breast and prostate cancers. There have been no head-to-head clinical trials comparing pamidronate and zoledronic acid among patients with advanced prostate cancer.

OBJECTIVE

To estimate the risk of developing an SRE among men with metastatic prostate cancer after being treated with either pamidronate or zoledronic acid.

METHODS

A retrospective cohort study was conducted, using data from Kaiser Permanente's Southern California Region. The cohort included men aged > or = 18 years diagnosed with prostate cancer from 1998 to 2004 who received at least 1 infusion of either pamidronate or zoledronic acid after their cancer diagnosis. Patients receiving both drugs and those with a documented SRE prior to diagnosis were excluded. The primary outcome of SREs was defined using diagnosis codes for fractures, spinal cord compression, radiation to bone, and hypercalcemia of malignancy. Secondary outcomes were deterioration in renal function, based on serum creatinine laboratory results, and mortality. Multivariate logistic regression was used to predict SREs and mortality risk for pamidronate compared to zoledronic acid. The proportion of patients with renal function deterioration was analyzed using chi(2) tests.

RESULTS

The cohort included 118 patients treated with pamidronate and 274 treated with zoledronic acid. Results showed no significant difference in risk of SREs for pamidronate versus zoledronic acid (OR 0.99; 95% CI 0.59 to 1.67; p = 0.98). No significant difference was found in renal function deterioration (chi(2) 2.08; p = 0.15) or mortality (OR 0.71; 95% CI 0.43 to 1.17; p = 0.18).

CONCLUSIONS

For patients with prostate cancer, the choice between these 2 bisphosphonates must be balanced between the shorter infusion time of zoledronic acid versus its increased costs. We found no evidence for a difference in outcomes; therefore, pamidronate is an effective choice where clinic capacity permits.

Electrolyte and salt disturbances in older people: causes, management and implications

Salt and electrolyte disturbances are commonly encountered in older patients. A sound understanding of the underlying physiological and pathological mechanisms underpinning the predisposition of older people to the common electrolyte imbalances can help clinicians minimize their considerable associated morbidity and mortality. This review focuses on the more common and clinically relevant salt and electrolyte disorders of older people. The epidemiology, causes, symptoms, diagnosis and treatment of hyponatraemia, hypernatraemia, hyperkalaemia, hypokalaemia and calcium and phosphate imbalance in old age are covered from a clinician's perspective.

Hypercalcemia and childhood cancer: a 7-year experience

Hypercalcemia is a rare but potentially fatal complication during the management of childhood cancer. The treatment of severe hypercalcemia in children has not been clearly defined. The authors present a retrospective series of 16 children (11 boys and 5 girls) with severe hypercalcemia (>/=2.9 mmol/L) treated between 1997 and 2004 for malignancy. Median serum calcium level was 3.14 mmol/L. Hypercalcemia was present at the initial diagnosis of cancer (eight patients) or occurred during treatment (five patients) or during relapse (three patients). Three children had several episodes of hypercalcemia. All children were treated by hydration for a median of 7 days (range 2-12 days). Eight patients received intravenous pamidronate. The other treatments were adapted to the mechanism of hypercalcemia. Serum calcium levels were lowered to below 3 mmol/L after a median of 2 days and to below 2.7 mmol/L after a median of 4 days after starting treatment. Pamidronate was well tolerated apart from one case of multifactorial renal failure. Intravenous pamidronate is a safe and effective treatment for severe cancer-related hypercalcemia in children. Specific therapy must be initiated as soon as possible. Serum calcium levels must be monitored for a fortnight after administration of pamidronate due to the risk of hypocalcemia.