“We get tested. We worry. We don’t live any longer.”
Oktober, 2025
This is a point of view from G. Welch , Physician and Senior Researcher at the Center for Surgery and Public Health, Brigham and Women’s Hospital, Boston, and author of “Less Medicine, More Health: 7 Assumptions That Lead to Too Much Medical Care.”
According to the author (and many others, such as P. Gotsche, a Danish doctor and researcher, and director and co-founder of the Nordic Cochrane Center, a group of independent experts, until 2018), screening does not allow people to live longer.
Welch demonstrates that interest groups greatly overestimate the benefits of cancer screening, while its harmful effects are real and too often ignored.
It does not save lives, but encourages healthy people to resort to unnecessary medical interventions, and propels them into a state of illness that these people would never have known without screening. The colossal sums that our societies devote to it would be better used in other public health areas, in the real prevention of disease risk factors, or in improving treatments and health care for people who are really sick.
A recent study we relayed on the Cancer Rose website suggests that current data do not support the claim that cancer screening tests save lives by extending lifespan, except perhaps for colorectal cancer screening by sigmoidoscopy.
The problem, Welch explains, is that cancers grow so quickly that screening cannot stop fast-growing cancers, those that are inherently poor prognostic and have characteristics that make them very fast-growing and detrimental from the outset.
Our article on the natural history of cancer illustrates how we are being fooled by a simplistic, but false, theoretical view of the cancer model, which suggests that all cancers are “stoppable ” at a certain stage of their development, guaranteeing protection against advanced forms.
A long, useless, sick journey
To quote the author:
“…For the rest of us screening is a long run for a short slide. The purpose of screening is to reduce the chance of dying from a specific cancer. But most of us cannot benefit, because most of us are not destined to die from cancer. So doctors have to screen many to potentially benefit a few. How few? For most of us, the chance of dying in the next ten years from any given single cancer is less than 1%. That means 99% go through screening for nothing.
In reality, far fewer than 1% of people screened receive it.
Because the problem is the “birds.” * These cancers grow so fast and are so aggressive that they have already spread by the time they are detected by screening. Screening can’t help the birds; the question is whether treatment can. And increasingly, it can. While screening proponents like to take credit for the decline in cancer mortality—pointing to how long people with small cancers diagnosed by screening survive (and ignoring the misleading effect of overdiagnosis )—the really good news is that our cancer treatments are improving. The decline in cancer mortality in the United States over the past few decades has been largely due to improved treatments and reduced smoking, not screening.”
* Editor’s note: this is how the author refers to very rapidly developing cancers.
Here you will find this diagram of the “farmyard” illustrating the variable growth rates of cancers, and explaining why screening does not work on “birds”
https://cancer-rose.fr/en/2023/02/20/interval-cancers-incidentalomas-the-losers-of-screening/
In other words, aggressive cancers are inherently aggressive, and that is why we do not anticipate them.
For the breast, those detected by repeated mammograms correspond to less severe and curable cancers, with a sufficiently long residence time in the breast so that screening can detect them, but some of which would be completely curable even if not screened, and some of which fuels overdiagnosis (notably in situ), which are useless diagnoses.
To understand, also read https://cancer-rose.fr/en/2017/06/10/are-small-breast-cancers-good-because-they-are-small-or-small-because-they-are-good/
By the time screening occurs (indicated by the red vertical line in the farmyard image), the “bird” cancers have already passed through and cannot be detected. On the other hand, a multitude of other, slower-moving cancers (rabbits, turtles, and snails) are detected, most of which, if undetected, would never have caused harm to people’s health. But once detected, they will be treated as if they were life-threatening.
“Rabbit” cancers are slow-growing; they eventually produce a clinical symptom, leading the person to seek medical help, and they can be detected by screening. However, this anticipation through screening does not change the final result; these are curable cancers, and people will die from another cause, whether detected or not.
We invite you to read the article on our website, which includes additional illustrations, clinical cases, and an explanatory video.
Regarding breast cancer, explains G. Welch, “women with slow-growing breast cancer, for example, do equally well whether their tumor is small or large, that is, whether their cancer is detected early or late. Doctors are finding that tumor biology, host response, and treatment efficacy are far more relevant to cancer prognosis than the time of diagnosis .”
(Read:https://cancer-rose.fr/en/2017/06/10/are-small-breast-cancers-good-because-they-are-small-or-small-because-they-are-good/)
Indeed, tumor size does not correlate with severity; a small cancer does not mean a good prognosis, and a large cancer does not mean that it is detrimental. And even then, size does not correlate with time; small does not mean early, but rather that the cancer is slow-growing and has a long residence time in the organ. A large cancer does not mean that it was caught too late, but that it had a shorter residence time in the breast, because it is fast-growing.
We must therefore move away from this linear, progressive pattern of cancer development; it simply does not reflect reality.
On the other hand, certain and known risks
Regarding the 99% of people who get tested for nothing, according to the author, it would not be so serious if screening did not carry a significant risk of harm to these 99%.
We quote the author again: “ Multi-cancer screening has been promoted as a way to increase the chances of saving lives. Researchers at the private healthcare company GRAIL, for example, have postulated that their screening test for 50 cancers would reduce the death rate from all cancers combined by 26% . Were that true, screening would almost certainly increase longevity since cancers make up roughly one-third of all deaths. Alas, it is almost certainly not true -and claims that screening will “save tens of thousands of lives” look to be nothing more than hype.”
(Read our report on the subject here:https://cancer-rose.fr/en/2022/09/15/liquid-biopsies-the-grail/)
A surprise guest has come to shatter all hopes placed in early cancer detection, overdiagnosis, or the detection of cancers that are useless to detect. This is the detection of a cancer that is not intended to cause symptoms or death during the patient’s lifetime, but which will be treated, since discovered, with the same aggressiveness as a “real” clinical cancer.
But this is not insignificant because it results in so much unnecessary overtreatment, which has a heavy impact on the lives of patients.
You will find all the detailed explanations of overdiagnosis and its consequences here:https://cancer-rose.fr/en/2021/10/23/what-is-overdiagnosis/
False alarms are another significant pitfall of screening. These are cancer suspicions based on imaging that are not confirmed, but only after multiple additional tests can it be confirmed that it was a false image. And this is not trivial.
To quote Welsch :
“False alarms can be extraordinarily common with regular screening: almost half of American women who undergo a ten year course of annual screening mammography will have at least one. It almost feels like a “cancer scare” has become a rite of passage for American women.(Editor’s note: not just for Americans, fear of cancer is the most devious and widely used driver in Pink October incentive marketing campaigns).
This all reminds me of what a mentor used to say: it’s hard to make a well person feel better. But it’s not that hard to make them feel worse.
Here’s my personal calculus with respect to prostate cancer. I know I could die from prostate cancer, but I also know I am far more likely to die from something else. Prostate cancer screening does lower the risk of prostate cancer death, but only a little bit. And, as with colorectal cancer, it does not affect longevity. For a 70-year-old male like me, the risk of prostate cancer death is about 1% in the next ten years, and screening might reduce that by one-quarter, to 0.75%. So, if I’m screened, then the chance that I avoid a prostate cancer death because of screening is 0.25%.”
(For prostate cancer screening, we invite you to read our article:https://cancer-rose.fr/en/2017/01/05/parallel-to-breast-screening-prostate-screening-overdiagnosis-as-well/
The emotional cost of waiting for results, undergoing additional invasive tests, and the ever-present fear of cancer, even when ultimately unfounded, is a significant, much-underestimated harm, plunging some more vulnerable people into prolonged anxiety -depressive syndromes.
Mammography screening is harmful and should be abandoned ( P.Gotsche )
This iconoclastic article by P. Gotsche, cited above, was published in 2015, already…. P. Gotsche is a Danish researcher and doctor. He was the director of the Nordic Cochrane Centre (a group of independent experts), and he is the co-founder of the Cochrane Collaboration.
We have enough studies and accumulated knowledge today that support Gotsche’s observations at the time.
He writes:
” As screening does not reduce the incidence of advanced cancers, we would not expect screening to have an effect on breast cancer mortality today. This is supported by observational studies. Denmark has a unique control group because, for 17 years, screening was only offered in 20% of the country. We found that the decline in breast cancer mortality in the relevant age group was 1% per year in the screening areas and 2% per year in the non-screening areas.14 “
” If we take into account the cardiac and lung cancer deaths caused by radiotherapy and rather generously assume that screening reduces breast cancer mortality by 20% and results in 20% overdiagnosis, in accordance with the Independent UK Panel,4 there appears to be no mortality benefit.21 This result can be discussed, e.g. modern radiotherapy may be less harmful, but considering that screening does not reduce the rate of advanced cancers and therefore cannot work, it seems likely to me that screening increases total mortality. It is also noteworthy that the randomised trials did not find a trace of an effect on total cancer mortality, including breast cancer mortality (relative risk 1.00), although this was expected given the claimed effect on breast cancer mortality1 “
This is consistent with another study suggesting that if we consider all the adverse effects of screening, the outcome is a zero-sum game (expected benefits in terms of lives saved counterbalanced by the same number of deaths attributable to the treatments).
And to conclude;
“Mammography screening has been promoted to the public with three simple promises that all appear to be wrong: It saves lives and breasts by catching the cancers early. Screening does not seem to make the women live longer; it increases mastectomies;1,25 and cancers are not caught early, they are caught very late.9 They are also caught in too great numbers. There is so much overdiagnosis that the best thing a women can do to lower her risk of becoming a breast cancer patient is to avoid going to screening, which will lower her risk by one-third.13 We have written an information leaflet that exists in 16 languages on www.cochrane.dk, which we hope will make it easier for a woman to make an informed decision about whether or not to go to screening.
I believe that if screening had been a drug, it would have been withdrawn from the market long ago. Many drugs are withdrawn although they benefit many patients, when serious harms are reported in rather few patients. The situation with mammography screening is the opposite: Very few, if any, will benefit, whereas many will be harmed. I therefore believe it is appropriate that a nationally appointed body in Switzerland has now recommended that mammography screening should be stopped because it is harmful.”
Consequences of these findings
We now need to conclude the knowledge we have accumulated about cancer: screening does not reduce mortality (treatments do), and it does not reduce the most aggressive cancers because it does not detect them. Treatments are working better and better. Screening carries risks.
Welch summarizes his findings thus: ” We have overstated the benefits of cancer screening—it’s not at all clear that it helps people live longer or live better. And we have understated its harms— drawing many more people into the system and exposing them to medical intervention.”
Screening is not very useful; its benefits are overestimated, and it can be truly harmful. It carries significant costs for individuals and society.
For breast cancer, 30% to 50% of cancers detected may be “unnecessary” detections. Thisphenomenon leads directly to overtreatment, where women undergo unnecessary biopsies, surgeries, chemotherapy, or radiation for these non-fatal conditions, with all the associated physical side effects, psychological distress, and financial burdens, some of which are fatal.
Overdiagnosis and overtreatment highlight a profound ethical dilemma inherent in mass screening. If a significant percentage of detected “cancers” are clinically insignificant, then the very act of screening, intended to save lives, paradoxically becomes a source of harm through unnecessary medicalization, anxiety, and invasive treatments. This is a critical questioning of the principle of “Primum non nocere ” (first do no harm) in the context of population-wide screening; the (unproven) collective benefit comes at an unacceptable cost for many people.
The work of our Cancer Rose collective is aligned with that of many international advocates for Informed Choice and Patient Empowerment.
The decision to undergo screening is inherently complex, as it depends on individuals’ personal experiences, life experiences, and beliefs.
But it is not necessarily complicated once knowledge is shared, and this is where we must make efforts, as doctors, public authorities, the media, and health authorities. The decision must be made for the individual, but above all, with the individual. This requires “fair information on the benefits and risks” of undergoing any medical procedure.
When will there be an intelligent Pink October, when will the historical momentum of Pink October, public pressure, commercial interests, and gendered reflexes finally give way to scientific evidence, nuanced discourse, and the autonomy of healthy people (especially women, who are overly medicalized from a young age)?
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