Why is detecting cancer early the biggest lever in treatment?

Question

Accepted Answer

_The survival math changes completely with the stage at which cancer is found._

> The biggest lever is to treat cancer early. Lung cancer is the number one killer of all cancers, it kills twice as many people as the second biggest. If you detect it at stage one, you have over a 60% survival rate after five years. If you detect it at stage four, you have an 8% chance of living five years from now, 92% will die. You can only treat it early if you diagnose it early.

Source: [Tomorrow's Medicine, with Cyriac Roeding (eCornell Keynote)](https://ecornell.cornell.edu/keynotes/view/K052126/)

Q&A, early detection

Why is detecting cancer early the biggest lever in treatment?