It’s unlikely for a colonoscopy to miss cancer of the areas of intestine that a colonoscopy covers , but there could be many other causes of blood in stool and altered bowel habits as you have mentioned .
May I please know you history in detail , could you please share your stool routine examination and colonoscopy reports
Next Steps
Get back with reports
Health Tips
Not all blood in stool are caused by cancer , it could be of many causes including inflammatory bowel disease . Or could be from lesion or causes above the upper limit of colon . I need more details from you to guide you further