I went the image showing all the different kinds of cancers
Its not hard to understands what the image is about because the title is straight forward but things that would simply make this better would be the addition of a key for one. A key gives a way to accurately interpret what it is we are looking at. Without one we are left to interpret it in our own way and not the way it was intended to be viewed. The second things is that some form of tabular data could be added to emphasize what we are looking at. Being doing that we can better understand the scope of the problem.
I remember receiving emails and graphs about the casualities while is was in the military but becase of poor design the information lost much of its impact.