Most NFAs are incompletely resected, because they are inaccessible for complete resection for the neurosurgeon due to the critical structures in this area. In case of residual disease, it has been reported that immediate postoperative radiation therapy results in high local control rates of 90-95%13 and that an active surveillance policy results in a high local recurrence rate (50-80%) within 10 to 15 years27. The reason to postpone radiation therapy in case of residual disease is that in most series ultimate local control rates with active surveillance policies, with salvage radiotherapy in case of regrowth, are similar to immediate postoperative radiation therapy. In addition, it has been assumed that delay of radiation therapy can prevent or delay hypopituitarism with its additional sequelae. One should be aware of the fact that the pituitary function is already affected in 50% of the cases immediately after first surgery54.