Talk to your doctor, and ask to be screened for all common cancers. A colonoscopy is in your future (I just had one). Also ask for a Prostate-Specific Antigen (PSA) Test. Also look into the HPV vaccine.
If you run out and get a bunch of random cancer tests, you are basically ensuring that you will get unnecessary and painful treatment for a finding that probably wouldn't have harmed you in the first place.
It's not a satisfying answer, but it's true. The reason most cancers are found late is because there's no effective alternative.
https://www.bmj.com/content/362/bmj.k3519
Colo , when appropriate , is good but not as a general interest test: