Before, during, and after my treatment I use 95% standardized and bioavailable curcuminoids supplements. In it's natural form it is not absorbed into the blood. Most reliable brands add piperine(black pepper extract). Because it is water soluble like vitamin C, it may be flushed from your system every couple of hours. I was already taking large dosage of "timed release" vitamin c and still do, but had to take the curcumin supplements about every 2-3 hours.
There don't seem to be any report downside to either curcumin or vitamin c unless you happen to be allergic to them.
FDA and American Cancer Society have not yet given approval for this. Many doctors and hospitals don't want holistics used because source, quality, and dosage is unknown and unpublished. My oncologist told me she could lose her license if she mentioned it to her patients.
Since I read that life expectancy for me was low, I searched for solutions. I have worked in computer programming(now IT) since 1966, and have a high degree of confidence in my ability to gather accurate and reliable information from quality sources.

There seem to be a very large number of studies and clinical trials being done all over the world. I read that England now has an extremely large one going on. I didn't want to die waiting for federal approval, but understand doctors and hospital concerns. I first looked at a Malaysian study on Lung cancer because it contained much detail and was well documented. I recommend you look for as much research as possible as it is being updated all the time. Any further questions, I will answer yto the best of my ability.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4699625/