https://cancercanbekilled.com/
This inspiring documentary provides at least one clue why HIGH DOSE vitamin C can be so effective against growing cancers. The Trojan horse effect. Both vitamin C and glucose enter through GLUT receptors, and cancer cells, requiring more energy for cell division, may have something like 10 times more of these glucose receptors (thank you Dr. Levy!). https://acsjournals.onlinelibrary.wiley.com/doi/abs/10.1002/1097-0142(19931115)72:10%3C2979::AID-CNCR2820721020%3E3.0.CO;2-X
High vitamin C concentrations will flood cancer cells, (Note: a ketogentic (low sugar) diet would also be helpful.) Vitamin C replaces the glucose that the cancers require for rapid cell division. But like alcohol in the brain, vitamin C isn't glucose and can't provide the energy.