Unfortunately, to date there is NO medical evidence or double blind studies showing that sugar or carbs can ‘feed’ cancer cells or make them grow - none!!
No matter what you do your own body will produce glucose through different means and if that is scarce will burn fats - and even muscle in starvation - to stay alive.
Cancer cells are even better at metabolizing different substrates to survive. A cancer researcher told me that she’s seen some cancer cells actually use the chemo and immuno agents to grow!! She said that some of the older, really harsh agents derived from mustard gas, etc really still work the best - but they take their toll on the healthy cells as well.
You will find tens of thousands of websites - some even from respected hospitals - perpetuating this sugar/cancer connection, but if you read them closely they are all just identical copies of an article or hypothesis written 50 years ago!