What Causes Cancer? Are Tumors And Cancers The Same?
Updated: Aug 29
First off, what is cancer? The dreaded "c" word that even my non-English speaking patients know. Is it the same as tumor?
What is a tumor?
A tumor refers to a solid mass of tissue (lump) that forms when abnormal cells grow uncontrollably and group together. This can develop almost anywhere in the body.
Normally, human cells grow and multiply to form new cells as the body needs them. When cells grow old or become damaged, they die, and new cells take their place. Sometimes this orderly process breaks down, and abnormal or damaged cells grow and multiply when they shouldn’t. These cells may form tumors, which are lumps of tissue. Tumors can be benign (non-cancerous) or cancerous
What is the difference between tumors and cancer?
The biggest difference between benign tumors (non-cancerous) vs cancer is the ability to spread into, or invade, nearby tissues and can travel to distant places in the body to form new tumors (a process called metastasis). This is also how cancer causes death when it spreads (metastasize) to the parts of the body outside the area where it originated from.
Although benign tumors do not spread or invade, they can cause problems when they cause compression effects to the surrounding tissues especially in areas with limited space such as the brain and the neck. In which case, they need to be removed via surgery. The good news is, once they are removed, they usually do not grow back.
So, what causes cancer?
Cancer is a genetic disease. That is, it is caused by changes to genes (pieces of DNA) that control the way our cells function, especially how they grow and divide.
Genetic changes that cause cancer can happen because:
- of errors that occur as cells divide.
- of damage to DNA caused by harmful substances in the environment, such as the chemicals in tobacco smoke and ultraviolet rays from the sun.
- they were inherited from our parents.
The body normally eliminates cells with damaged DNA before they turn cancerous. But the body’s ability to do so goes down as we age. This is part of the reason why there is a higher risk of cancer later in life.
While most genetic changes aren't harmful on their own, an accumulation of genetic changes over many years can turn healthy cells into cancerous cells. The vast majority of cancers occur by chance as a result of this process over time. Having said that, there are still many things we can do to reduce cancer risk and increase our chances of cancer survival. For example, we can stop smoking, reduce alcohol intake, participate in screening to allow early detection. It is a well known fact that early detection saves life as survival rates are much higher in early stage cancer. Furthermore, one may avoid the need for chemotherapy if the cancer is picked up early and removed.
Each person’s cancer has a unique combination of genetic changes. As the cancer continues to grow, additional changes will occur. Even within the same tumor, different cells may have different genetic changes. This is also what is driving one of the latest development in cancer research to allow individualized targeted therapy. We will discuss this in another post on how genetics and genomics affect breast cancer treatment.
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