3 ms·

"Early detecting causes harm" sounds absurd. That's akin to saying that "eating food" (and not dying from hunger) leads to harm from cancer treatment.

xxXXxx- 9y ago
No, it's not absurd at all. Cancer treatment is not benign and (believe it or not) not all cancers will always causes harm. https://sciencebasedmedicine.org/the-uncertainty-surrounding-mammography-continues/ https://sciencebasedmedicine.org/the-uncertainty-surrounding... For instance, in 2012 a study in the New England Journal of Medicine (NEJM) by Archie Bleyer and H. Gilbert Welch found that, while there had been a doubling in the number of cases of early stage breast cancer in the 30 years since mass mammographic screening programs had been instituted, this increase wasn’t associated with a comparable decrease in diagnoses of late stage cancers, as one would expect if early detection was taking early stage cancers out of the “cancer pool” by preventing their progression. That’s not to say that Bleyer and Welch didn’t find that late stage cancer diagnoses decreased, only that they didn’t decrease nearly as much as the diagnosis of early stage cancers increased, and they estimated the rate of overdiagnosis to be 31%. These results are in marked contrast to the promotion of mammography sometimes used by advocacy groups. Last year, the 25 year followup for the Canadian National Breast Screening Study (CNBSS) was published. The CNBSS is a large, randomized clinical trial started in the 1980s to examine the effect of mammographic screening on mortality. The conclusion thus far? That screening with mammography is not associated with a decrease in mortality from breast cancer. Naturally, there was pushback by radiology groups, but their arguments were, in general, not convincing. In any case, mammographic screening resulted in decreases in breast cancer mortality in randomized studies, but those studies were done decades ago, and treatments have improved markedly since, leaving open the question of whether it was the mammographic screening or better adjuvant treatments that caused the decrease in mortality from breast cancer that we have observed over the last 20 years.
xxXXxx- 9y ago
We also have a case study of over diagnosis from Korea: http://www.npr.org/sections/health-shots/2017/05/09/527569291/dont-screen-for-thyroid-cancer-task-force-says http://www.npr.org/sections/health-shots/2017/05/09/52756929... "South Korea is the poster child for the problem of overdiagnosis" of thyroid cancer, Welch says. About 15 years ago, doctors there started a mass campaign to screen for thyroid cancer. That vastly increased the rate of thyroid cancer, to the point that it exceeded cases of breast cancer and other common malignancies. Yet Welch notes that the mortality rate from this cancer didn't change at all. "So all these extra cases were cases of thyroid cancer that weren't destined to bother people," he said. Instead, that rash of overdiagnosis sent people into needless surgery. Harmless thyroid tumors are surprisingly common. Decades ago, pathologists in Finland noticed that more than a third of the people they saw in autopsy had thyroid tumors, but the cancers had no negative consequences.
jghn 9y ago
To echo the other responses with a practical example, suppose you were to have a slow growing prostate cancer. Suppose that there was a 0% chance it'd actually cause you any real harm. This is a not at all uncommon scenario. Now suppose an early screen detects this cancer. Since we still have difficulty discerning whether or not your cancer is really "bad" or not you'll likely undergo immediate treatment. This treatment leaves you feeling horribly ill for the duration with all sorts of side effects. After treatment you're left with urinary leakage and erectile dysfunction. I don't know about you but if you were to tell me that I could live the rest of my days with a minor cancer growing in my body minding its own business I'd choose leaving it there vs the side effects of the treatment.

xxXXxx- 9y ago

No, it's not absurd at all. Cancer treatment is not benign and (believe it or not) not all cancers will always causes harm. https://sciencebasedmedicine.org/the-uncertainty-surrounding-mammography-continues/ https://sciencebasedmedicine.org/the-uncertainty-surrounding... For instance, in 2012 a study in the New England Journal of Medicine (NEJM) by Archie Bleyer and H. Gilbert Welch found that, while there had been a doubling in the number of cases of early stage breast cancer in the 30 years since mass mammographic screening programs had been instituted, this increase wasn’t associated with a comparable decrease in diagnoses of late stage cancers, as one would expect if early detection was taking early stage cancers out of the “cancer pool” by preventing their progression. That’s not to say that Bleyer and Welch didn’t find that late stage cancer diagnoses decreased, only that they didn’t decrease nearly as much as the diagnosis of early stage cancers increased, and they estimated the rate of overdiagnosis to be 31%. These results are in marked contrast to the promotion of mammography sometimes used by advocacy groups. Last year, the 25 year followup for the Canadian National Breast Screening Study (CNBSS) was published. The CNBSS is a large, randomized clinical trial started in the 1980s to examine the effect of mammographic screening on mortality. The conclusion thus far? That screening with mammography is not associated with a decrease in mortality from breast cancer. Naturally, there was pushback by radiology groups, but their arguments were, in general, not convincing. In any case, mammographic screening resulted in decreases in breast cancer mortality in randomized studies, but those studies were done decades ago, and treatments have improved markedly since, leaving open the question of whether it was the mammographic screening or better adjuvant treatments that caused the decrease in mortality from breast cancer that we have observed over the last 20 years.

xxXXxx- 9y ago

We also have a case study of over diagnosis from Korea: http://www.npr.org/sections/health-shots/2017/05/09/527569291/dont-screen-for-thyroid-cancer-task-force-says http://www.npr.org/sections/health-shots/2017/05/09/52756929... "South Korea is the poster child for the problem of overdiagnosis" of thyroid cancer, Welch says. About 15 years ago, doctors there started a mass campaign to screen for thyroid cancer. That vastly increased the rate of thyroid cancer, to the point that it exceeded cases of breast cancer and other common malignancies. Yet Welch notes that the mortality rate from this cancer didn't change at all. "So all these extra cases were cases of thyroid cancer that weren't destined to bother people," he said. Instead, that rash of overdiagnosis sent people into needless surgery. Harmless thyroid tumors are surprisingly common. Decades ago, pathologists in Finland noticed that more than a third of the people they saw in autopsy had thyroid tumors, but the cancers had no negative consequences.

jghn 9y ago

To echo the other responses with a practical example, suppose you were to have a slow growing prostate cancer. Suppose that there was a 0% chance it'd actually cause you any real harm. This is a not at all uncommon scenario. Now suppose an early screen detects this cancer. Since we still have difficulty discerning whether or not your cancer is really "bad" or not you'll likely undergo immediate treatment. This treatment leaves you feeling horribly ill for the duration with all sorts of side effects. After treatment you're left with urinary leakage and erectile dysfunction. I don't know about you but if you were to tell me that I could live the rest of my days with a minor cancer growing in my body minding its own business I'd choose leaving it there vs the side effects of the treatment.