Does a keto diet help with cancer? i read on an ncbi article that cancer cannot process ketones unlike other cells in our body. does this effectively delay tumor progression? i could find any human trials, only in animals studies?

No one is still sure

Diet has some preventive role from developing cancer. But it is attained by simple weight reduction by cutting down calories, avoiding animal fats and avoiding red meats. If you add increased activity/Exercise you will get additional benefit. Keto diet has no special advantage in cancer prevention.

Would be marvelous if dietary measures really could reverse or cure cancer. Same for vitamins and supplements, BUT, at this point in time, there is no objective evidence to support such value. Anecdotal depictions do exist, but these appear to be exceptions, not the rule. Your doctor will be the first to know if and when a keto breakthrough occurs!