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Why is the heart rarely cancer?
Why is the heart rarely cancer? Cancer can occur in so many parts of the human body, but why is it rarely heard of heart cancer?
We have all heard of lung cancer, stomach cancer, liver cancer, kidney cancer… but we rarely hear of anyone who has “heart cancer”. Some people speculate that this may be due to the high heart temperature. In fact, in a quiet state, the most important heat-producing organ of the human body is the liver. Therefore, the heart is not the warmest organ, and the warmer liver is obviously more likely to get cancer.
So, why does the heart rarely get cancer?
Related to the structure of the heart
The heart is made up of myocardium. Cardiomyocytes are called “terminally differentiated cells”, which means that the life span of this kind of cells is the same as that of humans. They will no longer divide and proliferate after birth, and their number will remain unchanged. The occurrence and development of cancer rely on the continuous proliferation and differentiation of cancer cells. Therefore, primary cancers of cardiomyocytes are extremely rare.
Related to the unique anatomical position of the heart
The heart and blood vessels form a closed blood circulatory system, making it less susceptible to direct attack by harmful substances from outside. Many carcinogens that people face in life may cause varying degrees of damage to the nasopharynx, oral cavity, esophagus, gastrointestinal, lung, skin and other organs, and then cause malignant lesions.
Compared with these organs that are exposed to harmful substances every day, the heart, which lies deep in the core of the body, is less likely to be directly attacked by these carcinogens. Harmful substances entering the bloodstream can also be continuously purified as they pass through the liver, spleen and kidneys. After such a process, some harmful substances in the blood can hardly cause adverse effects on the heart.
Like primary cancer of the heart, metastatic cancer of the heart is extremely rare. Under normal circumstances, the blood transfer of cancer cells needs to be “set up” somewhere in the body, and the blood flow in the heart is too fast, and most cancer cells are taken out of the heart by the blood before they have a chance to stop.
In the lymphatic metastasis pathway, because the heart does not have lymph nodes, the lymphatic vessels of the heart return to the left and right lymphatic trunks, and there is no lymph flow from other parts to the heart, so it will not be affected.
In addition, the third way is the invasion of nearby organs. The lungs, trachea, esophagus, mediastinum, thymus, etc. around the heart do have tumors, and sometimes they invade towards the heart. The thin layer of connective tissue, but very dense and tough, sometimes clinically can see tumor metastasis causing pericardial effusion, but rarely further invades the heart.
Therefore, the heart is also a rare area for metastatic cancer.
It should be pointed out that although the myocardium occupies most of the heart, there is still a part of the heart that is blood vessels. Therefore, angiosarcoma still appears on the heart. In fact, angiosarcoma is also a common type of cardiac malignant tumor. In addition to angiosarcoma, rhabdomyosarcoma also appears in the heart, generally in infants and young children. But in general, the incidence of heart malignancies is very low.
(source:internet, reference only)