- What is cancer?
- What is colorectal cancer?
- What are the key statistics about colorectal cancer?
- What are the risk factors for colorectal cancer?
- Do we know what causes colorectal cancer?
- Can colorectal cancer be prevented?
- Can colorectal polyps and cancer be found early?
- Signs and symptoms of colorectal cancer
- How is colorectal cancer diagnosed?
- How is colorectal cancer staged?
- What are the survival rates for colorectal cancer by stage?
- How is colorectal cancer treated?
- Surgery for colon cancer
- Surgery for rectal cancer
- Ablation and embolization to treat colorectal cancer
- Radiation therapy for colorectal cancer
- Chemotherapy for colorectal cancer
- Targeted therapies for colorectal cancer
- Clinical trials for colorectal cancer
- Complementary and alternative therapies for colorectal cancer
- Treatment of colon cancer by stage
- Treatment of rectal cancer by stage
- More treatment information about colorectal cancer
- What should you ask your doctor about colorectal cancer?
- What happens after treatment for colorectal cancer?
- Can I get another cancer after having colorectal cancer?
- Lifestyle changes after treatment of colorectal cancer
- How does having colorectal cancer affect your emotional health?
- If treatment for colorectal cancer stops working
- What`s new in colorectal cancer research and treatment?
- Additional resources for colorectal cancer
- References: Colorectal cancer detailed guide
What is cancer?
The body is made up of trillions of living cells. Normal body cells grow, divide into new cells, and die in an orderly way. During the early years of a person's life, while they are still growing, their normal cells divide faster. Once the person becomes an adult, most cells divide only to replace worn-out or dying cells or to repair injuries.
Cancer begins when cells in a part of the body start to grow out of control. There are many kinds of cancer, but they all start because of out-of-control growth of abnormal cells.
Cancer cell growth is different from normal cell growth. Instead of dying, cancer cells continue to grow and form new, abnormal cells. In most cases the cancer cells form a tumor. Cancer cells can also invade (grow into) other tissues, something that normal cells cannot do. Growing out of control and invading other tissues are what makes a cell a cancer cell.
Cells become cancer cells because of damage to DNA. DNA is in every cell and directs all its actions. In a normal cell, when DNA is damaged the cell either repairs the damage or the cell dies. In cancer cells, the damaged DNA is not repaired, but the cell doesn't die like it should. Instead, this cell goes on making new cells that the body does not need. These new cells will all have the same damaged DNA as the first abnormal cell does.
People can inherit damaged DNA, but most often the DNA damage is caused by mistakes that happen while the normal cell is reproducing or by something in our environment. Sometimes the cause of the DNA damage is something obvious, like cigarette smoking. But often no clear cause is found.
Cancer cells often travel to other parts of the body, where they begin to grow and form new tumors that replace normal tissue. This process is called metastasis. It happens when the cancer cells get into the bloodstream or lymph vessels of our body.
No matter where a cancer may spread, it is always named for the place where it started. For example, breast cancer that has spread to the liver is still called breast cancer, not liver cancer
Different types of cancer can behave very differently. For example, lung cancer and breast cancer are very different diseases. They grow at different rates and respond to different treatments. This is why people with cancer need treatment that is aimed at their particular kind of cancer.
Not all tumors are cancerous. Tumors that aren't cancer are called benign. Benign tumors can cause problems – they can grow very large and press on healthy organs and tissues. But they cannot grow into (invade) other tissues. Because they can’t invade, they also can't spread to other parts of the body (metastasize). These tumors are rarely life threatening.
Last Medical Review: 10/15/2014
Last Revised: 02/27/2015