We would not know anything about how the body works without technology. Nor would we know that all of nature is a process of continuous expansion, unless somehow we were not learning by it, continuously expanding our knowledge.
Indeed you are right, a healthy body, quickly identifies and rectifies cancerous cells.
The body of all humans, connected by the internet as billions of independently thinking brains, with billions of eyes, is no different.
It soon recognises the bad cells masquerading as healthy, under a pseudonym but with ill intent, accusing others of that which itself is guilty, barking false orders, to think the way it thinks.
Good luck to you in your ambitions, I think you will need it, to begin learning about the way nature works.