My daughters horse had loads of sarcoids, they all seemed to come up at once, our vet came and looked at them but he didin't feel he could do much with them so refered him to The Royal Vets College Potters Bar. He was treated there over about eight or nine weeks, the first week he stayed there as they put him out and cut off about six/seven, he had chemo on another four/five and had about another six frozen. Once he was out of there, he was sore but fine he had to go back weekly and had to be re treated with the chemo for seven weeks (once each time we went back). He didn't have to stay over they treated him and he came home each night. It might have been different if we lived further away (we traveled about a hour/hour and a half) to get there. He spent a lot of time in the stable and hated being in for such a long time but it was worth it.
Two years on now he has no sign's of any coming back. Fingers crossed