Large scale meta studies dont provide any form of substantial evidence, they point to vague correlations, from which you can look for causation.

Feel free to do salutation to the false god of large scale metastudies :).

Here you already know causation. Early diagnosis is proven of great benefit for many diseases. It's more effective to specially study different groups of people and see what does and doesn't work.

Btw here breast cancer is biannual indeed, annual if you had it. Might differ per country.