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To be worried about false negatives with bowel screening kits?

(23 Posts)
Kaylasmum49 Wed 01-Feb-17 09:35:26

I've been reading a lot about people doing their bowel screening and it coming back negative only to be diagnosed with bowel cancer a few months later. This makes me wonder how effective this testing is.

I think I would want a colonoscopy to be sure but I realise that this wouldn't be financially viable.

Any thoughts?

Kaylasmum49 Wed 01-Feb-17 09:40:34

And also the false positives too!

ThisMorningWentBadly Wed 01-Feb-17 09:42:52

This worries me too.

DGF had lots of negative bowel screening then went in for something unrelated and discovered he had stage 3 bowel cancer. Not quite sure how they could have missed something so enormous.

Kaylasmum49 Wed 01-Feb-17 09:57:51

Sorry to hear that, hope he's doing ok.

Yeah it is very worrying, don't know what the solution could be.

TarragonChicken Wed 01-Feb-17 10:33:03

Unfortunately no screening test is going to be 100% sensitive or specific. They are a compromise, designed for people with no worrying symptoms to pick up (early) as many cases as possible without too many false positives.

If your screening is negative and you are otherwise well, you can be reasonably sure you don't have bowel cancer. If you have symptoms indicative of bowel cancer, then see your GP for more investigations.

StillMaidOfStars Wed 01-Feb-17 10:44:27

I lecture on health screening and supporting Tarragon above.

It is a screen, not a diagnosis.

wigglesrock Wed 01-Feb-17 11:01:00

My parents both did the screening test and it came back negative. Probably closer to a year later my Dad was diagnosed with bowel cancer, to reiterate what previous posters have said he went to the GP (probably a bit later than he should have, certainly later than my mum wanted him to). He had symptoms and a family history, he didn't rely on the test as a diagnosis or as reassurance. He was aware of symptoms, had a brilliant GP and quick surgery and follow on chemo. He's doing really very well now but he got to the Dr when he couldn't ignore the symptoms. It's not fool proof, it's not a guarantee.

KurriKurri Wed 01-Feb-17 11:02:46

In our health area they offer bowel scopes at 55 - which they do in the evenings at the hospital. I think these are a very good idea as they are presumably more effective.

On the other hand there is apparently a high percentage of people who won't do the bowel screening test and just throw it away when it arrives. So I imagine that folk would be even more reluctant to have a bowel scope.

Kaylasmum49 Wed 01-Feb-17 11:07:08

The bowel scope sounds like a great idea but I think it should be started at an earlier age, maybe 45?

pipsqueak25 Wed 01-Feb-17 11:10:42

if anyone has concerns about this / have unusual symptons they should firstly speak to their health care professional rather than relying on diy where there will always be more room for error.
gps would rather help and reassure people then do tests if required.

Kaylasmum49 Wed 01-Feb-17 11:48:31

Pip, of course you should see your gp if you have any worrying symptoms but the bowel screening is for people who are asymptomatic, but the false negatives concern me. You can't just demand a colonoscopy just because you're not sure that you can trust the screening results.

missyB1 Wed 01-Feb-17 11:58:19

I was one of the first bowel cancer screening specialist Nurses when we started the screening program. I always counselled patients about not relying purely on screening because of possible false negative (and you can get false positive) results, to always know the signs and symptoms of the disease, but also just to seek advice on any changes in their bowel habit.

Screening isn't a perfect tool, but its the most cost effective way to cover a large population. If you have the money the best advice i can give is have a one off colonoscopy, as evidence shows this can reduce your chances of dying from Bowel cancer - I will be having one next year when I turn 50.

Also dont be fobbed off by GPs if you have symptoms, insist on investigations.

ToadsforJustice Wed 01-Feb-17 12:19:57

www.bmj.com/content/356/bmj.i6673

Interesting paper that suggests that "in women aged 60 and over, incidence of colorectal cancer was not reduced by screening, possibly because of increased prevalence of cancers in the proximal colon in older women".

missyB1 Wed 01-Feb-17 14:57:37

Toads this is my problem with the flexi sig programme, its great for spotting lesions in the distal bowel obviously, but what about the rest of it? The problem is there just wouldn't be the capacity or resources to give everyone a Colonoscopy. I dont know what the answer is, but the current programme does at least seem to be working in some ways simply by polyp detection and removal in those with either a positive FOBt, or those with a polyp in the sigmoid found at flexi sig - they do then go on to have a Colonoscopy.

Kaylasmum49 Wed 01-Feb-17 16:40:37

I suppose we just have to accept that there's no way to be totally sure that we don't have bowel cancer apart from a colonoscopy and there's no way that would be possible to everyone on the nhs. All those people that have polyps and negative tests that will possibly end up with cancer is really scary. I have health anxiety and this is really worrying to me.

Penfold007 Wed 01-Feb-17 18:38:43

If your screening is negative and you are otherwise well, you can be reasonably sure you don't have bowel cancer. If you have symptoms indicative of bowel cancer, then see your GP for more investigations.

Tarragon my DH had several negative bowel screens and was symptom free. One episode of rectal bleeding and a very cautious GP he had a colonoscopy and was diagnosed with bowel cancer.
We asked the consultant and clinical nurse specialist two questions:
1. Has the tumour been there for some time? Yes
2. Why didn't the screening show it up? Unless the tumour is bleeding when the screening is done it won't show up
If you get offered screening take it up but be vigilant.

StillMaidOfStars Wed 01-Feb-17 19:29:03

It is virtually impossible to have a screening test that is 100% sensitive (identifies true positives) and 100% specific (identifies true negatives). If it were, it wouldn't be a screen, it would be a diagnostic test.

missyB1 Wed 01-Feb-17 19:37:04

Lets not forget breast screening isn't perfect either (mammogram didn't show my cancer). Screening programmes dont pick up all cancers, but they are still worthwhile. But we all need to be aware of our bodies and note any changes.

StillMaidOfStars Wed 01-Feb-17 19:52:43

I read in... hmm, some pop economics book that wasn't Freakonomics... that the UK mammogram programme saves, on average each year, the same 'amount' of life as every female cyclist (who wouldn't normally bother) wearing a helmet for one 15 min journey. So that money should go into helmet awareness, Not mammograms.

CrohnicallyPregnant Wed 01-Feb-17 19:54:19

Colonoscopies (and sigmoidoscopies) are not without risks. If you were offering them routinely as a screening tool, then the side effects and complications would likely outweigh the potential good it could do. Not to mention the financial cost. And the fact that many people just wouldn't do it due to fear of the process, not finding the time, and embarrassment.

The idea of a screening test is that it is low risk, easy to administer and financially viable.

It's like with cervical screening (smear tests). They should be done routinely, but if you have worrying symptoms in between then you still need to get checked out.

ghostyslovesheets Wed 01-Feb-17 19:54:51

the cut off point here is 45 - I have had 2 colonoscopies in the last month - I'd rather have a reliable non invasive test but I'd also rather have my polyps identified and removed!

missyB1 Thu 02-Feb-17 09:39:50

Chronically you are right there are risks attached to colonoscopy which is why patients should be assessed before they have the test, we dont have a "straight to test" policy in our Trust for this procedure. And in the screening programme patients are assessed and counselled by a specialist nurse.

Kaylasmum49 Thu 02-Feb-17 11:52:58

I suppose it's about living with uncertainty and being vigilant about your health. For me dealing with health anxiety it's the uncertainty that makes me very anxious. Waiting for test results sends me off into a major spiral of anxiety and depression so to go through all of that and still have no guarantees scares me so much.

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