Some people will lose body fat really fast, some slower no matter what they do. Usually naturally thinner people will lose quicker since they have high metabolism rates.
I appreciate you wanting to fast to shrink your benign tumor, but I hope you're under a doctor's supervision while doing so.
Seeing that you eat in the direction of vegetarian and raw and also what you've mention about your past eating habits, I think this site will be very helpful to you:
And even though you said your tumor is benign, here's a really fascinating video I think you will enjoy and maybe will give you a more sensible way to dissolving your tumor: