Tumor Treatment For Taz

Hello, 
I'm from a family of 4 and Taz is my 4 year old Rottweiler, and he's developed cancer, to help Taz make a full recovery and beat the cancer he needs surgery and several doses of Chemotherapy after the surgery has been finished, he is in so much pain at the moment and needs treatment urgently, but my family just can't afford to pay for it, so we hope that there is hope on here, our whole family loves Taz, despite his size he is the nicest dog you could ever meet, my sons, 3 and 6, love him to bits and would be utterly devastated if he died, we got a quote from the Vets of £1600, but simply cannot afford it all, please help if you can, as our family doesn't want to lose our best friend.
Thank you so much.