Squamous cell carcinoma of the lung, a cancer that usually affects smokers, can cause an increase of calcium within the bloodstream. The high blood calcium level causes a variety of symptoms and happens because the cancer cells release a substance that affects the kidneys and bones. This type of phenomenon is called paraneoplastic syndrome, and it occurs in many cancers.
Paraneoplastic Syndrome
The medical term paraneoplastic syndrome describes the symptoms a person has because their cancer cells are releasing a substance or because their antibodies are fighting back against the cancer cells, but are accidentally causing a reaction with the tissues or organs. As many as 20 percent of all cancer patients have this syndrome, according to Dr. Bruce Chabner, professor of Medicine at Harvard Medical School, in "The Merck Manual for Healthcare Professionals." Lung cancer can cause various paraneoplastic syndromes, including an increase in calcium.
Squamous Cell Carcinoma
Approximately 30 to 40 percent of all lung cancers are a type called squamous cell carcinoma. This type of lung cancer is usually found in smokers and develops in the main airway into the lungs. People might experience difficulty breathing and might cough up blood; they can develop pneumonia, a collapsed lung and abscesses. Those with this type of lung cancer might also develop excess calcium in their bloodstream.
Calcium Level and Squamous Cell Carcinoma
Whenever the calcium level becomes low, the parathyroid gland will secrete the parathyroid hormone. This hormone increases the calcium level by instructing the kidneys to reabsorb calcium and increase their production of the active type of vitamin D. It also tells bone cells to release calcium into the blood. Squamous cell carcinoma causes an increase in calcium because these cancer cells release PTHrP, or parathyroid hormone-related peptide.
Symptoms of High Blood Calcium Level
The normal range of calcium is 8.8 to 10.4 mg/dL. The PTHrP released by squamous cell carcinoma affects the kidneys and bones, and results in a high level of blood calcium. The medical term for this high blood level is hypercalcemia, which can cause many symptoms, including nausea, vomiting, muscle weakness, sever thirst, frequent nighttime urination, kidney stones, abdominal pain, constipation, mental confusion, coma and heart problems.
References
- "M.D. Anderson Manual of Medical Oncology"; Dr. Hagop Kantarjian et al; 2006
- "Schwartz's Principles of Surgery"; Dr. F. Charles Brunicardi; 2010
- Merck Manual for Healthcare Professionals: Disorders of Calcium Concentration
- Merck Manual for Healthcare Professionals: Paraneoplastic Syndromes
