Hi janesd

We are sorry about your sister's diagnosis. You asked about the effectiveness of intravenous vitamin C treatment.

There is no clear evidence yet to indicate vitamin C has any benefits for cancer patients. You can read more about the history behind using vitamin C as a treatment on our blog.

Looking at the bigger picture since this post was written, more research and clinical trials have been carried out to try and determine the effectiveness of high dose vitamin C as a cancer treatment. The results have been very mixed, with some research showing it can boost the power of cancer drugs when tested on cells grown in a lab or in animals. But other studies tell a different story and suggest vitamin C could interfere with some cancer treatments. For example scientists recently showed it might protect breast cancer cells from the drug tamoxifen.

Most of the clinical trials studying high dose vitamin C treatment are still at an early stage (phase I) and have only included small numbers of people. The few phase I trials that have finished and have results available looked at the safety and side effects of combining vitamin C with standard treatments for patients with cancers including pancreatic, breast, and multiple myeloma.

In most cases adding vitamin C to treatment was safe and caused few, if any side effects. However, one clinical trial where vitamin C was given alongside a particular chemotherapy drug had to be stopped early due to side effects and the cancers growing more aggressively, so there are signs that it is not safe for all cancer patients. You can read about this here 

Because the trials have been small and focused on determining the safety of vitamin C, there is little evidence that it has any benefits yet. Some studies found that adding vitamin C alleviated some of the side effects experienced by patients undergoing treatment, but due to the small numbers involved and the way some of these trials were carried out, the evidence is far from solid

And critically, there is certainly no evidence as yet from any clinical trial that vitamin C improves survival rates. Any potential benefits high dose vitamin C may have as a cancer treatment are still unclear. More research and further clinical trials are needed to determine if it really does improve quality of life for cancer patients, or help people live longer. More importantly, doctors need to find out if it interferes with some anti-cancer drugs, and whether it should only be used to treat certain types of cancer

I hope this information helps answer your question.

If you would like to talk to our specialist nurses about possible treatments for your sister, please call the team on freephone: 0808 800 4040 from Monday to Friday, 9am to 5pm.

Best wishes

Jane