Stereotactic Radiotherapy Treats Skull Base Tumors: Part 2 of

WASHINGTON, DC-Stereotactic radiotherapy is increasingly gaining favor as an attractive alternative to conventional surgery of the skull base and head and neck. A panel of experts at the recent annual meeting of the American Academy of Otolaryngology-Head and Neck Surgery discussed potential uses of stereotactic modalities in otolaryngology practices and agreed that optimal candidates still need to be defined for these procedures, but that this treatment option provides an opportunity for participation and leadership among otolaryngologists.

Tumors amenable to stereotactic radiotherapy (other than acoustic neuroma) include paraganglioma (most common), schwannoma, meningioma, malignant tumors in the posterior fossa, pituitary tumors, and rarer tumors such as craniopharyngioma, chondroblastoma, and chordosarcoma, said Stephen P. Cass, MD, Associate Professor of Otolaryngology at the University of Colorado Health Sciences Center in Denver.

Factors to consider when deciding between surgery and stereotactic radiotherapy include age of patient (the younger the patient, the higher the risk of regrowth and secondary radiation-induced tumors), operability of lesions, likelihood of at least near total resection, likelihood of cranial nerve or vascular morbidity, and primary versus recurrent tumor. Dr. Cass noted that surgery was the preferred option if the tumor is resectable with minimal morbidity, and he said that stereotactic radiotherapy is preferred for recurrent tumors.

He cautioned that watchful waiting should always be considered, especially for elderly patients. Also, it is important to assess whether the patient has a tumor-prone condition. Stereotactic radiotherapy should only be used if the lesion is well defined and if the adjacent structures can tolerate radiation exposure, he added.

In a series of 10 patients with paragangliomas treated with stereotactic radiotherapy at the University of Colorado, tumor control was 100% at 3- to 4.5-year follow-up. These were relatively large tumors, with a mean of 7.3 cm, he said. Three out of four patients with pulsatile tinnitus had resolution of this annoying symptom. Also, he has successfully treated five schwannomas of cranial nerves 7, 10, and 12.

In summary, Dr. Cass said that stereotactic radiotherapy is a reasonable option for various skull base tumors. The risk of acute toxicity is low, and short-term tumor control is excellent. Late complications can occur, he noted, but are rare.

Anterior Skull Base Tumors

Stereotactic radiotherapy is a valuable adjunct to minimally invasive surgery for anterior skull base tumors, which are difficult to access, said Pete S. Batra, MD, Assistant Professor of Surgery at the Cleveland Clinic Head and Neck Institute.