> Things like needle biopsy of the prostate can miss cancerous cells, unless you take 100 samples.
biopsies can cause a stable tumor to metastasize [0]. Sometimes medical screenings are useful, but when you’re looking for problems and don’t actually have symptoms, practitioners have an incentive to find something to treat you for. Ideally you’ll be fired as a patient, but I’ve heard of doctors who do procedures and operate every time they can possibly justify it (“he owes money to everyone.”)