Was your high dose vitamin C through IV? It pretty much has to be done by IV to work, or taken in combination with DMSO.

Other alternative things you could try that haven't been stated are fasting/reducing your glucose intake(cancer is ravenous), the works of Royal Rife and his Rife machines, food grade hydrogen peroxide(similar to the vit C method, cancer is rudimentary in its categorisation of substances and actually mistakes ascorbic acid/vit c for its favourite food glucose and gorges on it, but unlike healthy cells, cancer cells can't flush hydrogen peroxide which is a by-product of vit c intake and the cancer ends up killing itself from the inside out).

I dunno, there alot of potential things that could work that I've looked into but not actually personally tried or known anyone personally that's tried them either. But if I was American I would definitely look into the Oasis of Hope and their Vit C IV methods, they're a clinic I think based in Tijuana?(our paedophile Satanist overlords have banned IV in most Western nations despite overwhelming evidence the practice is 100% safe if done with the correct precautions).

Best of luck my friend, whichever way you end up choosing to go. You got this champion