Sci Snippet: Cancer vs. Tumor: What’s the difference?

It doesn’t matter to you what word you hear if you or a loved one is told by a doctor, “You have cancer” versus “You have a tumor.” Either way, there’s a wave of fear that is likely sustained through months, years, or a lifetime of treatment. It’s a diagnosis that nearly everyone has been touched by, so it’s something that everyone has talked about at one time or another.  The words tumor and cancer are typically used interchangeably, especially by people who are not in healthcare.  But it helps to know that there is an important distinction between cancer and a tumor when describing a mass of cells growing somewhere in the body.

The most important point is that a tumor DOES NOT mean cancer.  A tumor is a whole bunch of cells growing out of control (think of it as the cell turning on the gas pedal for cell division) creating a mass somewhere in the body.  Cancer, on the other hand, means that these cells have the potential to move and invade other parts of the body.A tumor can be benign (not cancer) or malignant (cancer).

Image of a benign meningioma. Thanks to Wikipedia for the image.

Image of a benign meningioma. Thanks to Wikipedia for the image.

What does it mean to be benign? A benign tumor still a huge mass of cells, and even though it may not spread to other parts of the body (the definition of malignancy and cancer), the mass could grow so large it presses against vital organs requiring surgical removal or causing death.  An example of a benign tumor is a meningioma.  This is a brain tumor that grows out of the covering of the brain and spinal cord, called the meninges, and although they do not typically spread to other places in the body (so they are not considered cancer), they do put pressure on the brain and spinal cord and usually have to be removed and may be treated with radiation.

benign_malignant

Thanks MedicineNet.com for the image

Cancer, on the other hand, is a tumor that has the potential to spread to other parts of the body, which is called malignancy.  This is one of the reasons that cancer is called cancer – from the Greek meaning crab because of the crab-leg like projections that are found in tumors that are invading neighboring tissue.  Tumors may be benign, malignant, or transition from something benign to something malignant.  For example, in the breast, masses of cells can form like papillomas that are a benign tumor that will not spread to other areas of the body. However, a breast cancer diagnosis implies that the breast tumor has the possibility to spread.  The only way to know whether a lump is a papilloma, breast cancer or something else is through a doctor and a biopsy.

It’s also important to note that not all cancers involve a tumor.  A great example of this are blood cancers that involve the increased growth of a particular type of blood cells, but will not have a tumor.

And in case you’re wondering where cysts fit into this, these are sacks filled with fluid, air or some semi-solid material. Cysts can be caused by a number of things including infection or clogging of glands. They may indicate a risk factor for a tumor or cancer, but are not cancerous themselves.

 

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