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 eval

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