Welcome to our forum

Welcome to the Bowel Cancer UK Community, a place for anyone affected by bowel cancer to talk about their experiences, share their knowledge and support each other. Please read our useful information pages for more information about the forum and Bowel Cancer UK.

Karen s

Can colonoscopy miss cancer

I had a colonoscopy 8 months ago clear for cancer but 3 polyps removed and diverticulitis diagnosed I'm now getting bleeding in stools going to Go on Monday can cancer be missed very worried thanks


Good morning @Karen s, I am sorry to hear about your health concerns but I must admit my first reaction was that it is great that the polyps taken during the colonoscopy in June were not showing signs of Bowel cancer. Diverticulitis obviously brings its own problems though.

To answer your question though, yes rarely a colonoscopy can miss something but in your case the diagnosis of diverticulitis would almost certainly explain the blood in the stools (I am not medically trained though).

You are absolutely right to have this checked out though and also maybe think about discussing with the Doctor your anxiety about having Bowel cancer - I hope that hasn’t offended you but from everything you have said it sounds as if you could do with working through this health anxiety with someone. Take very good care, Kim :x::x:

PS - In case you wondered I have moved your post from ‘Just Diagnosed’ to the more general ‘Welcome to the Forum’ section

Karen s

Thank you for your reply however there is a 7% incidence of bowel cancers not being detected during colonoscopy please see 2019 research on the bowel cancer UK website. I also see several people on this forum have posted that their cancers have been missed or undetected. Diverticulitis generally presents with a large volume of blood being passed and not small amounts on the stool.I do not have health anxiety about bowel cancer I am myself a mental health consultant working for the NHS but am concerned that following my diagnosis 8 months ago I am still seeing symptoms. I have discussed these with my Gp and she agrees that cancers may go undetected and also feels a repeat colonoscopy should be undertaken.I do not feel I have to discuss my mental health I only want to ensure that my issues have been investigated thoroughly and nothing has been missed. I am aware that I posted in the wrong thread People need to be aware that although colonoscopy is the gold standard test but it is not 100% accurate and people need to be an advocate for their own health .


Karen, if you don't really want/need any advice, outlined by your own research indicated above, don't post on here that you do. You are being chippy with people who are only trying to help.


@Karen s you write that you want your health issues to be investigated thoroughly - which I get. However, are you sure that ‘just’ having a colonoscopy is the optimal approach for that? I know nothing about diverticulitis (or treatments for it) other than that I have a friend who has it who experiences only very limited blood loss (that’s n=1, I know).
Even if diverticulitis does not normally come with small amounts of blood on stool, colonoscopies do not normally miss cancer, either. In your case I think I would ask to be referred to a gastroenterologist to discuss the optimal approach in your case. Perhaps that is a colonoscopy, but it could also be something else.

I had a somewhat unclear diagnosis (not bowel related) myself last year, and my consultant’s advice was not to repeatedly carry out the same exam several times in quick succession because just like a colonoscopy it carries with it a small but non-zero risk of negative effects, and anything that wasn’t spotted the first time was unlikely to have grown so much that it would be much more easily identified in (in my case) six months. That last point wasn’t something I had thought about myself until she mentioned it.
This line of reasoning may not apply in your situation at all, but it is something I would want to discuss with a specialist myself.