Hi
Its absolutely possible to heal cists. I have an experience of healing them myself. One of my freinds had cists and REIKI did help. Reiki works for everything...thats what I know and I beleive. It all depends on your intention and your mental state. If you are positive and your intention is focussed, you will definitely get the results.
Deepending on your state of mind, the healing time can vary, you can heal the cist in 1 day or 1 month.
Just remain focussed on what you want to achieve and keep doing healing and see the cist ultimately vanishing away.
Good Luck
Maitri