It depends upon the type, size and location of the tumor and the expertise of the surgeon. Patients with Cushings disease usually have small tumors (microadenomas) and are surgically cured about 90% of the time based on data published by expert pituitary surgeons. Patients with acromegaly often have larger, more invasive tumors which are harder to cure surgically. The success rate with growth-hormone secreting macroadenomas is about 60% in the best surgical series. Non-secreting tumors are often macroadenomas as well. Whether a macroadenoma can by completely removed depends upon whether it has grown into the cavernous sinus, bone, or elsewhere. If it has not grown into these areas, a surgical cure can often be achieved. If tumor has grown into an area where it is not possible or safe for the surgeon to operate, it may not be surgically curable. However, such tumors can often be de-bulked away from the optic nerves and chiasm, in order to protect vision. Radiation therapy may be required to control further growth.