The Real Reason You Never Hear About Heart Cancer

Pixel-Shot/ShutterstockLung cancer. Brain tumors. Breast cancer. Prostate cancer. Every organ in your body is vulnerable to creating abnormal cells that attack your healthy tissue, but there’s one body part where cancer just doesn’t seem to be “a thing.” Heart disease is the leading cause of death in the United States, according to the CDC, so why do you rarely hear about cardiac cancer?

Heart cancer does exist—it’s just incredibly rare. Primary heart cancer affects about 50 people in one million, says Salim Hayek, MD, a cardiologist at the University of Michigan’s Frankel Cardiovascular Center who specializes in cardio-oncology. To put that in perspective, about one in eight American women will be affected by invasive breast cancer. Here are 14 cancer warning signs doctors never ignore.

To understand why heart cancer is so rare, it’s important to know just how cancer grows and spreads. As cells are growing and dividing, a mutation can occur, whether from genetic or environmental factors, says Steve Xydas, MD, chief of the Columbia University Division of Cardiac and Thoracic Surgery at Mount Sinai Medical Center and co-director of the Mount Sinai Heart Institute. Those mutated cells start rapidly growing and dividing, ignoring signals designed to tell them to die. Eventually, they can form a cancerous tumor.

Ironically, the factors that make the heart so vulnerable to disease are also thought to make it less vulnerable to cancer, says Dr. Hayek. “Most cardiac muscle cells, also known as myocytes, cannot divide and grow in number,” he says. “These are cells that are so organized and specialized in their function that they have many mechanisms and checkpoints that will not allow them to return to an earlier stage of immaturity and regenerate.” Without being able to regenerate quickly, it’s hard for the heart to repair damage from cardiac events—but that also doesn’t leave the door open very wide for mutations to grow into cancer.

Meanwhile, the heart also might be better protected from environmental risk factors, says Dr. Xydas. “There is less ability to expose the heart to carcinogens, as opposed to inhaling smoke to the lungs, for instance,” he says. There are few risk factors for heart cancer, but some conditions, such as Carney complex, raise the risk of tumors. Check out these 28 things you think cause cancer but don’t.

Even then, the vast majority of heart tumors—including the ones associated with Carney complex—are benign, not cancerous. Unlike other benign lumps, which are generally harmless, these ones should be removed to keep them from blocking blood flow, says Dr. Xydas.

Cancer can spread to the heart from other areas—particularly from melanoma, leukemia, and lymphoma, or lung, breast, or esophageal cancers—although that’s considered metastatic cancer, rather than “heart cancer.” Nearly 10 percent of fatal cancer cases have spread to the heart, says Dr. Hayek. “These cancers, when metastasized, reach the heart commonly through the bloodstream, or by direct invasion through the surrounding tissues, like in breast cancer,” he says.

In the rare cases of heart cancer, symptoms tend to mimic other heart conditions: chest pain, palpitations, and shortness of breath, says Dr. Xydas. Fatigue and weight loss are also common, and the symptoms could differ depending on which side of the body is affected; tumors on the right side can spread to the lungs and cause shortness of breath, while ones on the left could lead to stroke if they go to the brain, he adds. Next, learn 30 simple ways you can prevent cancer.