You might want to ask your niece to try flax hulls. They contain lignans (SDG) that are converted to mammalian lignans such as enterodial (EL) and enterolactone (ED) by good bacteria there. ED and EL are powerful free radical scavengers and therefore great antioxidants. Many tests n trials have shown lignans particularly flax lignans to be very effective agains cancers especially breast, bowel and prostate.
In addition, a good probiotic is eseential to repopulate the bowel with friendly flora that can then act on the flax lignans when ingested. I hope your niece finds something that will really help her fight the dreaded cancer!!