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Your first four links are just random ultrasound device companies. Doctors are very well-versed in ultrasound technology so your claim that doctors refuse to le

Your first four links are just random ultrasound device companies. Doctors are very well-versed in ultrasound technology so your claim that doctors refuse to learn this is patently false. Full-body scans have been marketed for years by companies looking to drum up business for their machines, but they mostly lead to false positives. Notice how your fifth link clearly says it has helped people find “warning signs of potential cancer” instead of that it helps people find cancer? These machines are basically false positive generators in most cases. If someone had effectively infinite time and money to dedicate to routine cancer screenings from these machines, they are more likely to end up harmed by unnecessary procedures stemming from false positive results than they are to catch and remove a specific cancer occurring randomly in their bodies. Contrary to your claims, we do actually screen for certain cancers in cases where a clear net positive benefit can be demonstrated. Mammograms for breast cancer are one common example. Doctors definitely aren’t just burying their heads in sand. These are common research topics and the tradeoffs of false positives are constantly being investigated. Full-body screenings aren’t necessarily a net benefit.

sigmoid10 4y ago
There's also a lot of politics and social psychology involved in these things. From the government side, it can be decades between arranging, deploying and evaluating large scale, population-wide cancer screenings. These are timescales on which scientific consensus can easily change. Mammograms in particular are a touchy subject, since newer metastudies only show a statistically significant reduction in mortality for women above the age of 50 and below the age of 74 [1]. However, many policy makers still offer screenings starting at the age of 40 with no upper limit, despite evidence that annual mammograms will result in a false positive result over 10 years with up to 61% probability [2]. Below the age of 50, regular mammograms may even increase the risk of dying from breast cancer [3]. Ultrasound screenings on the other hand would be much safer from a radiation-exposure point of view and metastudies suggest they can detect cancers under difficult conditions more reliably, but they also suffer from more false positives [4]. This is where the social aspect comes in, where many woman fear getting their breasts removed for no reason. This is especially concerning when more than 50% of positive results are found to be false positives [5]. To summarize: It's really hard to figure out what amounts to "net positive benefit" when it comes to general public screenings. [1] https://www.aeaweb.org/articles?id=10.1257/jep.35.2.119 https://www.aeaweb.org/articles?id=10.1257/jep.35.2.119 [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3209800/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3209800/ [3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4189562/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4189562/ [4] https://bmccancer.biomedcentral.com/articles/10.1186/s12885-020-06992-1 https://bmccancer.biomedcentral.com/articles/10.1186/s12885-... [5] https://ebmh.bmj.com/content/16/4/115 https://ebmh.bmj.com/content/16/4/115
thaumasiotes 4y ago
> Contrary to your claims, we do actually screen for certain cancers in cases where a clear net positive benefit can be demonstrated. Mammograms for breast cancer are one common example. Not really; mammograms for breast cancer are commonly seen as an example of overscreening.

sigmoid10 4y ago

There's also a lot of politics and social psychology involved in these things. From the government side, it can be decades between arranging, deploying and evaluating large scale, population-wide cancer screenings. These are timescales on which scientific consensus can easily change. Mammograms in particular are a touchy subject, since newer metastudies only show a statistically significant reduction in mortality for women above the age of 50 and below the age of 74 [1]. However, many policy makers still offer screenings starting at the age of 40 with no upper limit, despite evidence that annual mammograms will result in a false positive result over 10 years with up to 61% probability [2]. Below the age of 50, regular mammograms may even increase the risk of dying from breast cancer [3]. Ultrasound screenings on the other hand would be much safer from a radiation-exposure point of view and metastudies suggest they can detect cancers under difficult conditions more reliably, but they also suffer from more false positives [4]. This is where the social aspect comes in, where many woman fear getting their breasts removed for no reason. This is especially concerning when more than 50% of positive results are found to be false positives [5]. To summarize: It's really hard to figure out what amounts to "net positive benefit" when it comes to general public screenings. [1] https://www.aeaweb.org/articles?id=10.1257/jep.35.2.119 https://www.aeaweb.org/articles?id=10.1257/jep.35.2.119 [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3209800/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3209800/ [3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4189562/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4189562/ [4] https://bmccancer.biomedcentral.com/articles/10.1186/s12885-020-06992-1 https://bmccancer.biomedcentral.com/articles/10.1186/s12885-... [5] https://ebmh.bmj.com/content/16/4/115 https://ebmh.bmj.com/content/16/4/115

thaumasiotes 4y ago

> Contrary to your claims, we do actually screen for certain cancers in cases where a clear net positive benefit can be demonstrated. Mammograms for breast cancer are one common example. Not really; mammograms for breast cancer are commonly seen as an example of overscreening.