Malignancy-associated Hypercalcemia

Malignancy-associated hypercalcemia is a condition where cancer causes abnormally high calcium levels in the blood. It happens when certain tumors release substances that raise calcium, or when cancer spreads to bones and releases calcium into the bloodstream. This is one of the most common metabolic complications in people with cancer.

Your bones store most of your body's calcium. Normally, your body carefully controls how much calcium stays in your blood. When cancer disrupts this balance, calcium levels can climb too high. Some tumors produce proteins that act like parathyroid hormone, which tells your body to release more calcium from bones. Other cancers directly destroy bone tissue, releasing stored calcium.

This condition most often occurs with lung cancer, breast cancer, kidney cancer, and blood cancers like multiple myeloma. It can develop at any stage of cancer but often signals advanced disease. High calcium levels can affect your kidneys, heart, digestive system, and brain if left untreated.

Many people with this condition experience symptoms that develop gradually. Common signs include:

• Extreme thirst and frequent urination
• Nausea, vomiting, and loss of appetite
• Constipation and abdominal pain
• Muscle weakness and bone pain
• Fatigue and confusion
• Difficulty concentrating and memory problems
• Irregular heartbeat
• Kidney stones or decreased kidney function

Some people may have mild symptoms at first that worsen as calcium levels continue to rise. In severe cases, extremely high calcium can cause serious confusion, loss of consciousness, or heart rhythm problems.

Cancer causes this condition in two main ways. First, some tumors produce proteins that mimic parathyroid hormone or release other substances that signal bones to release calcium. Second, when cancer spreads to bones, tumor cells can directly break down bone tissue, flooding the bloodstream with calcium. Lung cancer and breast cancer are the most common culprits, followed by kidney cancer, head and neck cancers, and blood cancers.

Your risk increases if you have advanced cancer, especially if it has spread to your bones. Being dehydrated makes the condition worse because your kidneys cannot filter excess calcium effectively. Certain cancer treatments and long periods of immobility can also raise your risk. The condition rarely occurs in early-stage cancer.

Doctors diagnose this condition by measuring calcium levels in your blood. A standard blood test called a serum calcium test shows whether your levels are elevated. Normal calcium ranges from 8.5 to 10.2 milligrams per deciliter. Levels above this range indicate hypercalcemia.

Your doctor will also measure parathyroid hormone levels to understand why calcium is high. In malignancy-associated hypercalcemia, PTH is usually low or normal, not elevated. This pattern helps distinguish cancer-related high calcium from other causes. Rite Aid offers PTH testing as an add-on to help monitor this condition. Additional tests may include kidney function tests, vitamin D levels, and imaging studies to assess bone involvement.

Treatment focuses on lowering calcium levels quickly and addressing the underlying cancer. Common approaches include:

• Intravenous fluids to rehydrate and help kidneys flush out excess calcium
• Bisphosphonate medications to slow bone breakdown
• Denosumab injections to reduce calcium release from bones
• Calcitonin to rapidly lower calcium in emergencies
• Dialysis in severe cases when kidneys are failing
• Cancer treatment with chemotherapy, radiation, or targeted therapies
• Limiting calcium-rich foods and vitamin D supplements
• Staying well hydrated with water and other fluids

Successfully treating the underlying cancer is the most effective long-term solution. Work closely with your oncology team to manage both the cancer and calcium levels. This condition requires medical treatment and cannot be managed with lifestyle changes alone.