These analyses are very crude. How do they work out spending on cancer care? They take total spending and get the % spent on cancer care. % spent on cancer care is a published figure, it is not calculated directly. In single payer systems, like Australia, the true costs of cancer care are probably submerged in broader healthcare spending. The comparison is also unfair because of drug costs. Essentially, drug companies know they can make a lot on cancer drugs in the USA [1]. This means that they are more willing to negotiate lower prices in other smaller countries. There is also the fact that the crazy legislation in the USA prevents price negotiations. The USA is in a way subsidising cancer drugs for the rest of the world.

I also think it is impossible to really compare cancer mortality between countries. My take on these figures is that given how big and dirty the USA is, they are doing remarkably well to have mortality that is significantly lower compared to smaller wealthy countries.

[1] Fig 1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5641070/