The closet we may ever get to a cancer cure, may be when it’s possible and feasible to change cellular DNA or RNA. We still don’t know much about how such treatment will effect genes and chromosomes in present or future generations.
If DNA or RNA is not sufficiently altered, the body of that patient will eventually revert to it’s inclination of producing cancerous cells in various organs and under various conditions. Sort of like the tendency for a body to grow fat even after the person has managed to lose a lot of weight. Eventually, the weight begins to accumulate for most people. I think much of such latency is inheirited.
I think CRISPR technology has a good shot at doing this. Not just for cancer but for everything that is DNA related.
Last I heard you don't grow more fat cells. You just add to their size depending on diet and exercise.