How can doctors detect cancer at the earliest stage?

Actually, "stage zero" isn't quite cancer itself, but rather precancerous changes that haven't yet turned into a tumor, so the term is a bit conditional.

Screenings do help catch these conditions, but here's the catch: often cancer in very early stages doesn't show any symptoms at all, and you won't detect it on your own. Plus regular check-ups aren't a cure-all - the results depend on the type of cancer and honestly on luck too.

So the main thing is not to rely only on yourself, but to have a screening plan based on your age and risk factors, preferably discuss it with your doctor.

The main thing is not to rely on self-checks and internet diagnosis. People often get scared after reading symptoms online, or do the opposite and ignore warning signs, thinking they're nothing serious. "Stage zero" is actually precancerous changes (like polyps in the colon, atypical cells in the cervix) that haven't become a tumor yet but could. You can only catch that exact moment with instrumental methods: colonoscopy, mammography, cytology, PET-CT. On your own, you can really only notice obvious signs (a strange lump, blood in your urine) and rush to see a doctor.

The most effective thing is screening based on age and risk factors. Some people need mammography from 40-50 years old, some need colonoscopy from 45, some need blood tests for tumor markers. It's all individual, and this should be prescribed by a specialist who'll also explain what exactly you need to check and how often 😊

I know one woman who had a preventive mammography "just to tick a box" and they found microcalcifications - barely noticeable changes she would never have felt herself. She got treated, and everything turned out fine. That's what catching a problem in time really means.