The American Cancer Society states that there will be approximately 1.6 million new cases of cancer diagnosed in 2011. They also note that 571,950 Americans will die of cancer, or about 1,500 people per day in 2011. Stage IV cancer is the last stage of cancer and usually implies that the cancer has spread from its origin to other organs including the bones. This can cause an increase in the level of calcium in the blood.
Calcium
Calcium is a required electrolyte for the proper functioning of muscle contractions, nerve conduction, hormone release and blood clotting, according to the Merck Manual Online Medical Library. A balanced calcium level is maintained by dietary intake of calcium, absorption of calcium from the GI tract and renal calcium excretion. Almost all of the body's calcium is stored in bone. The normal serum calcium level ranges from 8.8 to 10.4 mg/dL.
Hypercalcemia
Blood calcium levels are considered high when they are greater than 10.4 mg/dL. According to the Merck Manual Online Library, hypercalcemia or high blood calcium is usually the result of excessive bone resorption. The most common causes of excessive bone resorption are hyperparathyroidism and cancer.
Cancer
Hypercalcemia in cancer patients usually happens in hospitalized patients. Humoral hypercalcemia of cancer occurs when there is no or minimal bone metastasis. This type of excessive bone resorption is seen in squamous cell carcinoma, renal cell carcinoma, breast cancer, prostate cancer and ovarian cancer. Some cancers, such as multiple myeloma, lymphoma and lymphosarcomas, can cause hypercalcemia by making cytokines or proteins that stimulate osteoclasts or cells that resorb bone. When the tumor metastasizes or spreads to the bone, hypercalcemia will also occur.
Symptoms of Hypercalcemia
Signs and symptoms of hypercalcemia will vary. In mild hypercalcemia most patients are asymptomatic. As levels start to rise, patients may become constipated or suffer a loss of appetite, nausea, vomiting, abdominal pain and a slowdown of bowel function. Elevation of serum calcium greater than 12 mg/dL may cause confusion, delirium, psychosis, stupor or coma. Patients may suffer with muscle weakness, and prolonged hypercalcemia can produce renal failure.
