Colorectal cancer grows slowly and does not cause symptoms for a long time.
The first symptoms of colon cancer are usually vague, like weight loss (due to loss of appetite when the cancer is located at the left side of colon or rectum, the tumor mass signals fullness) and tiredness (due to chronic bleeding, that can be unrecognized when the cancer is located at the right colon).
When the tumor grows to a larger size, local bowel symptoms start to manifest, like changed frequency and form of stool, feeling of incomplete bowl movement, rectal bleeding, bowel pain, bloating and vomiting of stool-like material.