For most common cancers like breast, colon, and lung, treatments have primarily extended median survival by months or a few years, rather than increasing overall survival.

Whole-body MRI screening in healthy adults produces more incidentaloma harm than cancer-mortality benefit.

Starting colonoscopy screening at 45 (vs 50) prevents enough early-onset cancers to justify the population cost.

Multi-cancer liquid-biopsy tests like Galleri detect early cancers at a stage that meaningfully improves survival.