Colorectal cancer is cancer that occurs in the colon or rectum. Sometimes it is called colon cancer, for short. As the drawing shows, the colon is the large intestine or large bowel. The rectum is the passageway that connects the colon to the anus. Sometimes abnormal growths, called polyps, form in the colon or rectum. Over time, some polyps may turn into cancer. 

Symptoms:
Colorectal polyps and colorectal cancer don’t always cause symptoms, especially at first. Someone could have polyps or colorectal cancer and not know it. That is why getting screened regularly for colorectal cancer is so important.

The symptoms are

• A change in bowel habits.
• Blood in or on your stool (bowel movement).
• Diarrhea, constipation, or feeling that the bowel does not empty all the way.
• Abdominal pain, aches, or cramps that don’t go away.
• Losing weight and you don’t know why.

Cause:
Cancer may be caused by genetic mutations, either inherited or acquired. These mutations don’t guarantee you’ll develop colorectal cancer, but they do increase your chances.

Some mutations may cause abnormal cells to accumulate in the lining of the colon, forming polyps. These are small, benign growths.

Removing these growths through surgery can be a preventive measure. Untreated polyps can become cancerous.

Treatment:
Screening tests can find polyps so they can be removed before turning into cancer. Screening also helps find colorectal cancer at an early stage, when treatment works best.

Survival rate:
Having a colorectal cancer diagnosis can be worrying, but this type of cancer is extremely treatable, especially when caught early.
The 5-year survival rate for all stages of colon cancer is estimated to be 63 percent based on data from 2009 to 2015. For rectal cancer, the 5-year survival rate is 67 percent.
The 5-year survival rate reflects the percentage of people who survived at least 5 years after diagnosis.
Treatment measures have also come a long way for more advanced cases of colon cancer.