There is a lot of misinformation out there about vitamin C, as well as overstating its benefit for some kinds of cancer. Regardless, it is a valuable vitamin worthy of study and may have some role in cancer treatment.
High doses of vitamin C to improve cancer treatment passes human safety trial: https://medicalxpress.com/news/2017-03-high-doses-vitamin-cancer-treatment.html
High doses of vitamin C to improve cancer treatment passes human safety trial: https://medicalxpress.com/news/2017-03-high-doses-vitamin-cancer-treatment.html