Difference between cancer and tumor

What is the difference between cancer and tumor?

Pawel Malczewski
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What is Cancer? (1)National Cancer Institute. Cancer. Available here.

Cancer encompasses more than 100 diseases. All of these diseases have one thing in common: an abnormal and uncontrollable cell growth that can lead to serious illness and eventually death.

The cancer starts with DNA damage in some cells. This DNA damage can occur due to various factors, some of which are well known and recently confirmed by the WHO (for example, the chemicals in processed meats). Since DNA contains instructions on how the cell should live and die, when the newly damaged DNA takes over, it changes those instructions. It may decide, for instance, that it is not a time to die but rather to multiply, passing on the damaged DNA.

Cancers can spread by releasing its cells to the blood stream or lymph vessels and then traveling to other parts of the body where it can multiply. Cancers maintain the name of its origins – for instance, colon cancer that spread to the lungs is still a metastatic colon cancer and not a lung cancer.

Most cancers form tumors (lumps). However, there are cancers that are not tumors. For example, leukemia doesn’t usually form a lump, but instead circulates and grows in the blood and blood-forming organs.

What is a Tumor? (2)Johns Hopkins Medicine. What are tumors? Available here.

A tumor is an abnormal mass of tissue (lump) that results when cells divide more than they should or do not die when they should. They are divided into two groups: benign (noncancerous) or malignant (cancerous). It is also called neoplasm.

Benign tumors, unlike cancers, don’t invade other tissues, don’t metastasize and are rarely life-threatening. They can, however, cause other problems. If the tumor cells start expanding uncontrollably, it can then form a lump that is large enough to press on the surrounding tissues or organs.

Not all tumors are cancers.

References   [ + ]

1. National Cancer Institute. Cancer. Available here.
2. Johns Hopkins Medicine. What are tumors? Available here.