They do it when there is a big tumor load, which is constantly breaking down and being detoxed by the liver, these enemas help the liver release these toxins and remove them from the intestines. Gerson's therapy is usually done with a help from another person/clinic. It is very time consuming.
Given the fact you don't have overt cancer, but a supposedly pre-cancerous cyst, you may take from Gerson's therpay whatever fits your case.
Like for exmaple the juicing idea - easy to absorb organic nutrients.
The recipe for their soup should also be of value to you, I feel. Also they state: easy to digest food, so the body can focus its energy on healing, instead of digesting.
When it comes to elimination, I would ask - do you eliminate proper amount and as many times as you eat. If not = possible backlog. I am not big specialist on psyllium. One thing I know about it : you need to take it with a lot of fluids.