1. From Data: Assume equal or worse cancer rates in the US and similar levels of cures across US and Europe (cancer rates are indeed worse in the US and Europe does have good cancer treatment on par with US)
2. OP claimed: People delay diagnosis in the US
2a. From data/science: Delayed diagnosis => Higher death rate
3. Deduction from 1 and 2, and 2a.: Higher death rate in the US
4. Data: Lower death rate in the US
5. Contradiction: 3 and 4
6. Reductio: We have a contradiction. We have to negate one of our assumptions or more. We can't throw away data, so we can only throw away OP's claim (2).
I agree there may be some folks in the US who delay diagnosis but population-wise, data doesn't support that.
https://arxiv.org/pdf/2304.10558