Adverse Effects of Screening and Over-Diagnosis

[MINTVCX]

I know the screening is very important thing especially when we talk about liver when often there are no symptoms. However please read below to have better view of screening generally (scientific point of view).

"Adverse Effects of Screening

At first glance screening would seem to be a good thing to do, but there are consequences to screening that carry a cost, and the potential benefits of screening need to be weighed against the risks, especially in subsets of the population that have low prevalence of disease!

There are two important down sides to screening:

false positives, people who test positive even though they really don't have disease, an

false negatives, people who test negative even though they really have disease.

Specifically, one needs to consider what happens to the people who had a positive screening test but turned out not to have the disease (false positives). Women between 20-30 years old can get breast cancer, but the probability is extremely low (and the sensitivity of mammography is low because younger women have denser breast tissue). Not only will the yield be low, but many of the false positives will be subjected to extreme anxiety and worry. They may also undergo invasive diagnostic tests such as needle biopsy and surgical biopsy unnecessarily. In the case of fecal blood testing for colorectal cancer, patients with positive screening tests will undergo colonoscopy, which is expensive, inconvenient, and uncomfortable, and it carries its own risks such as accidental perforation of the colon. Such complications are uncommon, but they do occur. The other problem is false negatives, who will be reassured that they don't have disease, when they really do. These hazards of screening must be considered before a screening program is undertaken.

For a very relevant look at this, see the following brief article from the New York Times on the potential harms of screening for prostate cancer. Link to the article

Over-Diagnosis

There is concern among some that there is an inordinate emphasis on early diagnosis of disease and that the increasingly aggressive pursuit of abnormalities among people without symptoms is leading to actually harm and great cost without reaping any benefits. For an interesting perspective, see the following essay, Link to "What's Making Us Sick Is an Epidemic of Diagnoses," in the New York Times by Gilbert Welch, Lisa Schwartz, and Steven Woloshin.

This is an article in the New York Times (Tara Parker-Pope: Link to "Scientists Seek to Rein In Diagnoses of Cancer") in which the problem of over-diagnosis is discussed."

sphweb.bumc.bu.edu/otlt/mph...

[Fibro2021]

This is not the first time you have addressed this topic. In my opinion, it's relevant for medical research and scientific articles in journals. For a particular patient at the appointment with a particular doctor, there is not much benefit, since this patient can be in both the false-negative and false-positive range of the scale. Only an assessment of the totality of all factors for a particular patient will help to avoid "medical errors".

I want to clarify that I am a supporter of early screening of diseases.

[AyrshireK]

However, in UK where early screening and intervention is lacking. Far too many people are diagnosed with liver disease far too late - 1/4 of those who are diagnosed after emergency admission to hospital with advanced liver disease actually die within 60 days.

My hubbies condition could potentially have been picked up by early screening - he had no obvious risk factors for liver disease and yet ended up almost dying from decompensated cirrhosis.

The British Liver Trust currently has an appeal ongoing to push for earlier identification and interventions in liver disease. britishlivertrust.org.uk/so...

You mention breast cancer screening and the risk of false positives in younger ladies - in the UK we only have routine breast screening for ladies between the ages of 50 & 71 (every 3 years). I had to have an emergency mammogram after a scare about 12 years ago - thankfully I got the all clear after lump was removed.

[MINTVCX]

Yes complex diagnosis is needed every time. I am not against screening but it should be done according recommendations. For example if you have concern about your liver do not start with fibroscan first. Check first FIB-4, ultrasound and symptoms. And if you do fibroscan anyway (without obvious reasons) be aware that false positive is more likely. Or use different cut-off for general population (I read about 9,2 kpa for >= F2 in one article).

Anyway I think it is important to be aware of it at least. Yes "patient can be in both the false-negative and false-positive range of the scale" but I would like to know as patient the probability of both (PPV or NPV) if this can be somehow provided.

[Fibro2021]

The low probability will never be zero. This may be a false signal for the patient, I think so.

[MINTVCX in reply to Fibro2021]

But there is difference between low and high probability. Please read mu story below although it was not mu fault about too much testing. True story.

I was a blood donor for some couple of years. After one donation I was infomed that one of screening test for one of infectious disease was positive/reatcive (they informed me about it without confirmation test which was a mistake). But they said instead the test was highly accurate (which was true) and I was very probably infected. But I was even before test in low risk population for this disease so after positive result I had higher chance for false positive statistically than true positive. But the test was done and I had to wait for confirmation test which turned out negative. Of course meanwhile I was very uncertain about the result (no one could say I was for 100% sure not infected moreover the disease was rather serious).

Afterward I checked statistics. Amongst blood donors in my country only 2.6% of reatcive/positive screening tests are true positive. But amongst high risk population for this disease (someone who has risky situation to be infected) above 90%-95% tests are true positive after confirmation test. You can say what the bad test in the first option but in fact it was exactly the same test... So for me this information would have made a difference (although I should not have been informed about the result without confirmation in the first place).

[Fibro2021 in reply to MINTVCX]

Rechecking positive test results is a common procedure. In any case, without confirming additional studies, the absence of a problem cannot be ruled out.

[MINTVCX in reply to Fibro2021]

Ok screening tests are needed but it should be done with scientic attitude. No health system is able to test everyone for every disease as general screening. I have also feeling even doctors are not aware about PPV or NPV for tests.

[Fibro2021 in reply to MINTVCX]

Actually, I'm not arguing with you. I also support the view that the correct diagnosis should be made as early as possible, but not at autopsy.

[pushthrough]

Mine flew under the radar for a while. Partially due to not having my annual because of Covid. I have a feeling reported liver disease cases will sky rocket in the next few years. It took a mental toll on a lot of people. We might have ran out of toilet paper in the states but alcohol shelves were always stocked.

[MINTVCX in reply to pushthrough]

Good point but please see the situation in Poland for example where we have war just behind our border and we know what Russians are able to behave from our history. Moreover to see all this terrible horror of Ukrainians is hard to stand...

[pushthrough in reply to MINTVCX]

Mint my heart goes out to the Ukrainians and you. I can’t imagine being near that or in it. I really can’t. I can’t even watch the news. Stay safe.