You can Google and see more symptoms. Things like unexplained weight loss and overall fatigue are signs. They also say "gas" can be a sign, and I actually did notice I was "tooting" a lot more than normal, although after a certain amount of time, you forget what normal is. I'm not sure if that itself was another symptom, but it certainly was part of my overall feeling of my situation that did lead me to book the doctor appointment.

Colon cancer usually comes with incomplete evacuation, traces/bloody stool, any surprising/major change in bowel habits. Many other diseases have similar symptoms(IBD) so it's difficult to distinguish a bit. In general, any kind of inflammation in body could be a trigger to cancer.