early detection is great, if you're being specifically checked for cancer. the problem is that you can have tumors growing inside you for years, and during that time, the effects of those tumors may lead your doctor to misdiagnose the problem. And by the time those tumors make themselves painfully obvious, you've got Stage 4 cancer which is pretty much a death sentence.

In the US you can order your doctor to arrange a cancer screening for you (scan or blood test), if you are worried you may have cancer. It's your money, after all. In other countries such as Canada, that's not so easily done. You're at the mercy of whatever doctor you've ended up with, and that doctor is not going to do anything for you unless it makes sense to him.

This has basically been my experience, anyhow. Thanks to my doctor's inaction I have maybe 6 months to live.