Colon cancers usually have sypmtoms such as alternating constipation and diarrhea, bleeding may or may not be present.
Next Steps
screening for colon cancer usually consists of yearly colonoscopy but recommended above the age 50-55 years.
It can be done at a younger age in people who have history of colon cancers in the family.
Ct scan usually is not done to detect cancers.
Health Tips
At your age group its highly unlikely, eat lots of salad (after proper washing), drink lots of water, avoid red meat and workout regularly.
You should do fine !