As mentioned in this article on our science blog, there's currently no evidence from any clinical trial that shows Vitamin C improves cancer survival. That doesn’t mean to say it won’t be of benefit to some patients one day but at the moment it isn't known how safe it is to take alongside conventional treatment that is known to work. It's also possible that in some situations it may interfere with the way chemotherapy works, which may make treatment less effective.
Due to this we would recommend speaking to your medical team first before pursuing this.
