It is unclear how often residual neoplastic cells will remain inert and how often they will continue to grow. It is possible that residual viable tumor will generate a recurrence over a few years time. Thus, while an early reduction in tumor volume is a hopeful sign, there is concern, based upon the radiobiology of these tumors, that eventual regrowth may occur in a substantial number of radiated tumors. One dilemma in AN patients is the often relatively minor nature of their symptoms at the time of diagnosis. While surgical excision is curative, it is accompanied with an appreciable morbidity.
Stereotactic radiotherapy is associated with a similar spectrum of functional deficits as surgery.
While the rate of deterioration was most marked in the first year, further losses continue well beyond this time. Clearly, stereotactic radiation cannot be thought of as a reliable hearing conservation therapy. Some have advocated radiating early lesions in NF-2 patients to forestall the onset of bilateral profound deafness. Based upon the published radiotherapeutic data, most NF-2 patients are best not considered radiotherapy candidates at least until the tumor ear has lost hearing. Other cranial nerve complications occurred with less frequency than hearing loss.