Lung cancer kills more Americans than any other type of cancer, according to statistics from the 2007 Centers for Disease Control and Prevention. A largely preventable disease that strikes smokers more than any other group, lung cancer can affect bone even when the cancer doesn't metastasize, leading to problems with high calcium levels in your blood, known as hypercalcemia. It appears that high dietary calcium levels may also increase the risk that smokers will develop lung cancer.
High Dietary Calcium Intake Risk
A study conducted by researchers from the Harvard School of Public Health looked at the effects of dietary iron, zinc and calcium intake on the risk of developing lung cancer. The study, published in the November 2005 issue of "Epidemiology," found that dietary calcium intake greater than 1270 mg per day increased the risk of developing lung cancer by 50 percent, with the risks highest among current smokers.
Paraneoplastic Syndromes Affecting Calcium
People with lung cancer, along with those who have other cancers, such as breast, kidney and prostate cancer, may develop paraneoplastic syndromes that affect bone. Paraneoplastic syndromes occur when an organ not directly invaded by the cancer is nonetheless affected by the cancer, according to Onconurse.com. Hypercalcemia develops most often in people with cancer of the epithelial tissue, which lines the organs, blood vessels and body cavities. This includes squamous cell lung cancers, according to the Ohio State University Research website. In non-small-cell lung cancer, which includes squamous cell cancer, hypercalcemia can develop when overstimulated parathyroid glands induce excess calcium release from bone. Harmful cytokines released from the tumor also stimulate calcium release from the bone into the bloodstream.
Metastasis in the Bone
Lung cancer metastasizes into the bone between 30 and 40 percent of cases, the Bone and Cancer Foundation reports. Cancer cells produce parathyroid hormone-related protein, which increases the breakdown of bone and the release of calcium. The release of calcium from the bone also releases growth factor, a substance that increases the growth of cancer cells. This creates a vicious cycle of bone breakdown stimulating more cancer cells, which leads to more bone breakdown, according to the Bone and Cancer Foundation.
Calcium-Sensing Receptors in Lung Cancer
Researchers from Ohio State University recently verified the presence of a protein found on the surface of lung cancer cells called the calcium-sensing receptor. The calcium-sensing receptor releases a hormone that causes bone breakdown throughout the entire body. Calcium that can't filter through the kidneys returns to the receptors, which then release more of the hormone, leading to more bone breakdown.
References
- Ohio State University Research; Scientists Discover Key Component in Lethal Lung Cancer Complication; Emily Caldwell
- CancerHelp UK: High Calcium in People with Cancer
- Bone and Cancer Foundation; What Lung Cancer Patients Need to Know About Bone Health; 2008
- NutraIngredients.com; Iron, Calcium Linked to Lung Cancer; Stephen Daniells; December 2005
- Centers for Disease Control and Prevention; Lung Cancer; February 2011
- Onconurse.com: Symptoms of Lung Cancer
