High Calcium Levels or Hypercalcemia

Approved by the Cancer.Net Editorial Board, 07/2018

Hypercalcemia is when a person has a higher than usual level of calcium in the blood. About 10% to 20% of people with cancer develop hypercalcemia.

Hypercalcemia can be life threatening and should be treated seriously. Treatment to relieve symptoms and side effects, such as hypercalcemia, is an important part of cancer care. This approach is called supportive or palliative care. Talk with your health care team about any symptoms you experience. This should include any new symptoms or a change in symptoms.

About calcium in the body

Bones have the highest amount of calcium in the body. About 1% of the body’s calcium is in the blood. Calcium is important for many bodily functions. It helps with bone formation and muscle, nerve, and brain function.

The body controls the level of calcium in the blood in many ways. The parathyroid gland, which releases parathyroid hormone, and the kidneys help control blood calcium levels. Vitamin D also helps the body absorb calcium from food. Vitamin D and parathyroid hormone work to adjust calcium levels in the bone and kidneys.

Causes of hypercalcemia

Cancer can cause high levels of blood calcium in several ways. It is important to note that hypercalcemia in people with cancer is not caused by having too much calcium in the diet. This means that eating fewer dairy products and other high-calcium foods does not help to reduce calcium levels in the blood.

The causes of cancer-related hypercalcemia include:

  • Bone-related cancers, such as multiple myeloma or leukemia, or cancer that has spread to the bone cause the bone to break down. This releases excess calcium into the blood.

  • Some tumors make a protein that acts very similar to parathyroid hormone. This protein causes the bone to release calcium into the blood.

  • Some cancers affect how well the kidneys can remove excess calcium from the blood.

  • Dehydration caused by nausea and vomiting makes it hard for the kidneys to remove calcium from the blood properly.

  • Lack of physical activity can cause bone to break down, releasing calcium into the blood.

Cancers that may cause hypercalcemia include:

  • Lung cancer

  • Head and neck cancers

  • Multiple myeloma

  • Kidney cancer

  • Breast cancer

  • Gastrointestinal cancers

Learn more about specific types of cancer.

Symptoms of hypercalcemia

The symptoms of hypercalcemia often develop slowly. They may be similar to the symptoms of cancer or cancer treatment. The severity of a person’s symptoms is not related to the level of calcium in the blood. Many people have no symptoms. And older patients usually have more symptoms than younger patients.

People with hypercalcemia may have the following symptoms:

  • Loss of appetite

  • Nausea and vomiting

  • Constipation and abdominal pain

  • Increased thirst and frequent urination

  • Fatigue, weakness, and muscle pain

  • Confusion, disorientation, and difficulty thinking

  • Headaches

  • Depression

Symptoms of severe hypercalcemia may include:

  • Kidney stones, a painful condition in which salt and minerals form solid masses called “stones” in the kidneys or urinary tract

  • Irregular heartbeat

  • Heart attack

  • Loss of consciousness

  • Coma

People with cancer and their families should know and seek treatment for any of these serious symptoms.

Diagnosing and managing hypercalcemia

Your doctor can diagnose hypercalcemia by doing a blood test to check the level of calcium in your body. You may also receive other blood tests to check kidney function.

Once hypercalcemia is diagnosed, your doctor will manage your condition based on how severe it is.

Mild hypercalcemia.
People who have no symptoms receive extra fluids, usually given through a vein. This helps the kidneys remove excess calcium.

Moderate or severe hypercalcemia. This can be managed by:

  • Treating the cancer

  • Replacing fluids lost through vomiting, frequent urination, or other reasons

  • Taking medicines to help stop the breakdown of bone. These include:

    • Zoledronic acid (Zometa)

    • Pamidronate (Aredia) or Ibandronate (Boniva)

    • Denosumab (Prolia, Xgeva)

  • Taking steroid. Steroids help decrease the breakdown of bone and increase calcium uptake from food. But steroids can somtimes increase the risk of osteoporosis and the breakdown of bone.

  • Using dialysis for people with kidney failure. Dialysis is a mechanized filtering process that removes excess waste from the blood.

Treating hypercalcemia improves the severity of symptoms and quality of life. In turn, this makes it easier to complete cancer treatment. Yet, sometimes hypercalcemia suggests that a person is approaching the last weeks of life. This may be true when there is no longer an effective treatment for the cancer.

Preventing hypercalcemia

The following tips may help keep hypercalcemia from getting worse:

  • Drink fluids

  • Control nausea and vomiting

  • Walk and be active, which helps prevent bone from breaking down

  • Check with your doctor before taking any medications, as some may make hypercalcemia worse

Related Resources

Dehydration

Advanced Cancer