This article suggests that short term fasting helps fighting cancer by making cancer cells more vulnerable while at the same time making normal healthy cells even more resistant to stress, this can help in chemotherapy.
However it also suggests that long term fasting might be enough to keep cancer at bay.
But it also demonstrates that in some types of cancers fasting, autophagy ( the act of the body eating itself) promotes cancer growth and adaptations to stress.
How does a vegan diet compare? Does the vegan diet promote some cancers? Does the vegan diet only reduce the chance of developing a cancer but doesn't suppress it once you already have one? Or is the vegan diet equal to fasting, helping some cancers and suppressing others?
If the question needs to be more focused, then what about the most common types of cancer; colo-rectal and breast cancer.
If the question is already good without needing to be more specific, then please ignore the last part.