Overdiagnosis

This is the polyp pathway UK radiologists and surgeons follow (a UK author, Foley, leads it). It is a surveillance-and-surgery guideline built on low to moderate quality evidence, and the Kaiser Permanente cohort published two years earlier questions whether following small polyps finds cancer at all.

The document that defines who is offered a scan in the United States, and therefore the document any argument about the screening eligibility gap has to engage with. Eligibility is still defined by pack-years and years since quitting rather than by an individual risk estimate.

The largest natural history study of gallbladder polyps undermines the surveillance half of the 2022 European guideline: small polyps grow as a matter of course and almost never become cancer, while size at first scan carries most of the risk.

Size is a blunt tool: a 10 mm cut-off sends many people with cholesterol polyps to surgery and misses some neoplastic polyps below it. Better imaging (contrast-enhanced or endoscopic ultrasound) or a risk score is the research need the 2022 guideline itself acknowledges.

The clearest evidence that radical treatment of localised prostate cancer saves lives when the cancer was found clinically rather than by a blood test, and the clearest single statement of what grade does: a Gleason score above 7 carried ten times the risk of death of a score of 6 or lower in the same trial.

The current shape of the screening question in the United States, and the best short statement of the trade-off in numbers a man can weigh. The three-to-one ratio between metastatic cases prevented and deaths prevented is also the argument for using metastatic presentation, not mortality, to judge a screening programme sooner.

The trial that made observation a defensible choice for low-risk prostate cancer found by a blood test, and that supplied the number a man needs when weighing surgery: the progression it prevents is mostly progression on a scan or a blood test, and the harms it causes are felt every day.

The honest state of the overdiagnosis question. Prostate cancer is common in the prostates of men who die of something else, screening finds a proportion of it, and how much of that is harm depends on what is done next. The fix is not a better estimate but fewer treatments for the cancers that do not need them.