The National Cancer Institute funds about 11% of new R01s, which is the mechanism that funds most academic labs. Their payline is among the lowest of the NIH’s Institutes, though to some extent this might be because they are one of the largest institutes and people chase the money: you could probably find a home for any proposal at two or three institutes. More data here: https://report.nih.gov/success_rates/Success_ByIC.cfm

With a few exceptions, the NSF doesn’t fund things that directly address diseases, so it’s hard to find a number for cancer specifically. Nevertheless, the overall payline is pretty similar.

That said, I’d argue that the solution is not (just) more money, but massive changes in how we fund and organize research too.