How many forms of cancer can you name? Perhaps a celebrity died of this cancer, or your friend survived that cancer. Dan Fogelberg died of Prostate cancer, and Jane Fonda is a breast cancer surviver. My list is as follows: skin (melanoma), bone, brain, mouth / throat (often from smoking or chewing tobacco), thyroid, lung, esophagus, breast, stomach, colon, liver, pancreas, ovaries, bladder, testicles, uterus, cervix, prostate, blood (leukemia), and lymphatic system (lymphoma). What major organ is conspicuously absent from this list? Well the title of this article is rather a spoiler - the heart. Cancer never seems to attack the heart - and why not?
At this point even a first year biology student would urge caution. The first rule of life on earth is, "Never say never."
Nothing can survive boiling water … except for a few thermophiles, heat resistant bacteria that thrive in hot springs.
Mammals never lay eggs … except for the echidna and the duck-billed platypus.
No animal (larger than a spore) can survive in the vacuum of space for a week … except for the tardigrade, a tiny 8 legged creature no bigger than a grain of rice. Shattering other records, a tardigrade can withstand temperatures of 150 C (300 F), a hot oven, or 1 degree above absolute 0, for a few minutes. It could take a quick dip in liquid helium and survive - unbelievable!
Every living thing ultimately depends on the sun for its life energy … except for certain archae that metabolize hydrogen sulfide spewing out of vents at the sea floor.
With this in mind, yes, heart cancer exists, but it is extremely rare. Cancer can spread from other organs to the heart, lung cancer in particular, but what about cancer that originates in the heart? It happens, usually as a sarcoma. The Mayo Clinic sees one case of heart cancer per year.
Another cancer that you've probably never heard of is cancer of the bicep or tricep. Since the heart is also a muscle, this suggests a generalization: muscular tissue is rarely afflicted with cancer. But it happens. Like the heart, cancer can occur in muscles, or joints, or even fat tissue. These are soft tissue sarcomas, and they can occur anywhere in the body. In 2015 there were approximately 11,900 cases of soft tissue sarcoma in the United States, that's one in 32,700 people, and only a small percentage of these sarcomas happen to form in the heart. Most of these cancers are survivable.
Benign tumors are more common. In particular, the smooth muscle of the uterus is susceptible to benign tumors, and these are called fibroids. My wife has several. She's had them for 40 years and they don't cause any trouble. Actually they did have a serious impact on her life prior to 2014; she was uninsurable, deemed a bad risk. It's hard to believe, but corporate America was unwilling to insure my wife due to her fibroids - imagine what they would say if she had a serious condition. Finally president Obama said Nix to preexisting conditions. Wendy can now purchase coverage from healthcare.gov, although she can't afford any of the policies. Well it's a step in the right direction I suppose. Eventually someone will drag our country, kicking and screaming, into the civilized world of Universal Healthcare.
So why are some cancers, such as breast cancer, common, while others are extremely rare? The short and perhaps oversimplified answer is, they are different diseases. We call them all cancers but they aren't the same. That is why we aren't going to cure "cancer" any time soon, though we may find a cure or effective treatment for one type of cancer, then another, then another. Among this cadres of diseases, some are more common than others, and some are more deadly. Obviously the common, deadly forms should receive the highest priority.