Recently saw a story about Elephants not developing it too and are being studied at a Ele-Retirement home in Fl
For them it may be an all leafy green diet?
This article comments on how elephants are equipped with so many more copies of a cancer preventing mechanism than Humans.
See the part of the article where it says:
Part of the explanation came in October 2015. The elephant genome turned out to contain a lot of copies of a known cancer-fighting gene. Known as p53, it is a tumour suppressor. Most mammals have it, including humans, but we only have one copy whereas elephants have 20.