Hypercalcaemia: historical perspectives and present management

[Tumor-induced hypercalcemia. Review of bisphosphonate treatment]

INTRODUCTION

The incidence of tumor-induced hypercalcemia is between 10 to 20%. New treatments justify this review article.

CURRENT KNOWLEDGE AND KEY POINTS

Tumor-induced hypercalcemia (half of all hypercalcemia) is divided into two groups: hematological tumors (10%), and solid tumors (90%), with osteolytic hypercalcemia and humoral hypercalcemia of malignancy (HHM: mediators include PTHrP). The two most common causes of tumor-induced hypercalcemia are lung cancer and breast cancer. Tumor-induced hypercalcemia most commonly disturbs gastrointestinal, neurological, renal and cardiovascular functions. These symptoms may be erroneously attributed to the underlying malignancy or its therapy. Prognosis of tumor-induced hypercalcemia is very poor, with median survival being about 3 months. Bisphosphonates have emerged as the standard treatment of tumor-induced hypercalcemia. The intravenous administration of isotonic saline is the first step in the management of tumor-induced hypercalcemia. Specific treatment of cancer remains essential to prevent TIH relapse.

FUTURE PROSPECTS AND PROJECTS

New bisphosphonates have appeared, the most potent known bisphosphonate today is zoledronate.

Treatment of tumour-induced hypercalcaemia in advanced breast cancer patients with three different doses of disodium pamidronate adapted to the initial level of calcaemia

A group of 38 female patients with advanced breast cancer experiencing the first occurrence of tumour-induced hypercalcaemia (TIH), mostly with osteolytic progressive bone metastases, were included in a prospective calcaemia-adapted study using three different doses of pamidronate (30 mg, 45 mg and 60 mg). Serum calcium normalisation was achieved in 29/38 (76%) patients. Comparison of the response rate in three therapeutic groups confirmed the need for higher doses of pamidronate in moderate TIH. Our study also emphasised the importance of effective anticancer systemic therapy.

Rehydration in palliative and terminal care: if not--why not?

Patients who are in the last few days of life are often too frail to take oral fluids and nutrition. This may be due entirely to the natural history of their disease, although the use of sedative drugs for symptom relief may contribute to a reduced level of consciousness and thus a reduced oral intake. Rehydration with intravenous (i.v.) fluids is the usual response in acute care settings, whereas the hospice movement has often argued against this approach. The issues are complex and involve not only physical, psychological and social concerns, but also ethical dilemmas. A review of the literature gives conflicting reports of the physical discomfort that may be attributed to dehydration in dying patients. There are many confounding variables, including the concomitant use of antisecretory drugs, mouth breathing and oral infection. It remains unproven whether i.v. fluids offer symptomatic relief in this situation. Hospice doctors are concerned that the use of i.v. fluids gives confusing messages to relatives about the role of medical intervention at this stage in a patient's illness. A drip may cause a physical barrier between a patient and their loved one at this important time. The use of other methods of fluid replacement are discussed. In the absence of definitive research in this area, the balance of the burdens and benefits of such treatment remains subjective. The prime goal of any treatment in terminal care should be the comfort of the patient. Decisions should be made on an individual basis, involving both patients and their carers wherever possible. Prolonging life in such circumstances is of secondary concern and i.v. fluids given in this context may be futile. The ethical dilemmas of withholding and withdrawing medical treatment in addition to those of conducting research in this area are discussed.

Reversible delirium in terminally ill patients

Delirium is reported to be a common problem in terminally ill patients. The poor prognosis given to these patients may result in the failure to recognize the causes that are easily treated and may be reversible. We present four patients in whom a comprehensive assessment revealed a number of reversible causes of delirium, resulting in a treatment approach that significantly improved the patients' cognition and quality of life.