Is that a good or a bad thing? something will always be number one. Would you prefer muder or overdose be higher?
The relevent question is if it is too high or a problem worth making significant changes to address.
Yes, cancer should be number one. Automobiles should be number 8 or lower, both because we can so something about it and because it's unnecessary. Cancer is a product of living and we're already devoting many resources to it.