Why Do Scientists Estimate That at Least Ten Times More

Why do scientists estimate that at least ten times more lives could be saved if we focused on prevention rather than treatment of cancer?

A) Education programs to ensure people know what prevents cancer would be easy to put in place and always work because people listen and understand the risk.
B) All the things that increase risk of cancer can be prevented.
C) The treatments for cancer often kill the patients before the cancer does.
D) This doesn't make any sense because we're getting better and better at treating cancer.
E) Even though we're getting better at treating cancer, the treatments are still not always successful and people die of the disease.