Faculty Bibliography

PURPOSE: To better evaluate tumor control and toxicity from radiosurgery for brain metastases, we analyzed these outcomes in patients who had survived at least 1 year after radiosurgery. METHODS AND MATERIALS: We evaluated the results of gamma knife stereotactic radiosurgery (SRS) for 208 brain metastases in 137 patients who were followed for a median of 18 months (range 12-122) after radiosurgery. The median patient age was 53 years (range 3-83). Ninety-nine patients had solitary metastases. Thirty-eight had multiple tumors. Sixty-nine patients underwent initial SRS with whole brain radiotherapy (WBRT), 39 had initial SRS alone, and 27 patients had failed prior WBRT. The median treatment volume was 1.9 cm(3) (range 0.05-21.2). The median marginal tumor dose was 16 Gy (range 12-25). The most common histologic types included non-small-cell lung cancer, breast cancer, melanoma, and renal cell carcinoma, which comprised 37.0%, 22.6%, 13.0%, and 9.13% of the lesions, respectively. Forty-five tumors were associated with extensive edema. RESULTS: At 1 and 5 years, the local tumor control rate was 89.6% +/- 2.1% and 62.8% +/- 6.9%, distal intracranial relapse occurred in 23% +/- 3.6% and 67.1% +/- 8.7%, and postradiosurgical sequelae developed in 2.8% +/- 1.2% and 11.4% +/- 3.5% of patients, respectively. Multivariate analysis found that local control decreased with tumor volume (p = 0.0002), SRS without WBRT (p = 0.008), and extensive edema (p = 0.024); distal intracranial recurrence correlated with younger patient age (p = 0.0018); and postradiosurgical sequelae increased with increasing tumor volume (p = 0.0085). CONCLUSION: Long-term control of brain metastases and complication rates in this selective series of patients surviving >or=1 year after radiosurgery were similar to previously reported actuarial estimates. Large metastases and metastases associated with extensive edema can be difficult to control by radiosurgery, particularly without WBRT.

BACKGROUND: Stereotactic radiosurgery is the principal therapeutic alternative to resecting benign intracranial tumors. The goals of radiosurgery are the long-term prevention of tumor growth, the maintenance of patient function, and the prevention of new neurological deficits or adverse radiation effects. Evaluation of long-term outcomes more than 10 years after radiosurgery is needed. METHODS: We evaluated 285 consecutive patients who underwent radiosurgery for benign intracranial tumors between 1987 and 1992. Serial imaging studies were obtained, and clinical evaluations were performed. Our series included 157 patients with vestibular schwannomas, 85 patients with meningiomas, 28 patients with pituitary adenomas, 10 patients with other cranial nerve schwannomas, and 5 patients with craniopharyngiomas. Prior surgical resection had been performed in 44% of these patients, and prior radiotherapy had been administered in 5%. The median follow-up period was 10 years. RESULTS: Overall, 95% of the 285 patients in this series had imaging-defined local tumor control (63% had tumor regression, and 32% had no further tumor growth). The actuarial tumor control rate at 15 years was 93.7%. In 5% of the patients, delayed tumor growth was identified. Resection was performed after radiosurgery in 13 patients (5%). No patient developed a radiation-induced tumor. Eighty-one percent of the patients were still alive at the time of this analysis. Normal facial nerve function was maintained in 95% of patients who had normal function before undergoing treatment for acoustic neuromas. CONCLUSION: Stereotactic radiosurgery provided high rates of tumor growth control, often with tumor regression, and low morbidity rates in patients with benign intracranial tumors when evaluated over the long term. This study supports radiosurgery as a reliable alternative to surgical resection for selected patients with benign intracranial tumors.

BACKGROUND: Aggressive (atypical or malignant) meningiomas are difficult tumors to manage. We review the local control and survival rates of patients with aggressive meningiomas after multi-modality therapy that included stereotactic radiosurgery (SRS). METHODS: Thirty patients had SRS for treatment of malignant (n = 12) or atypical (n = 18) meningiomas. There were 17 (57%) males and 13 (43%) females with an average age of 58 years. The mean number of prior surgical resections was two. The median imaging follow-up was 2.3 (0.1-11.4) years; median clinical follow-up was 3.8 (0.25-11.5) years. RESULTS: After SRS, the overall median time until progression of neurologic signs was 48.0 (+/-6.51) months. Median time to neurologic progression was significantly worse for patients treated late after recurrence versus early after craniotomy. Atypical meningiomas had 5- and 10-year overall actuarial survival rates of 59% (+/-13), while malignant meningiomas had 5- and 10-year overall actuarial survival rates of 59% (+/-16) and 0%. These curves were not significantly different from one another. Atypical meningiomas had a 5-year progression-free survival (PFS) of 83% (+/-7%), while malignant meningiomas had a 5-year PFS of 72% (+/-10) (p = 0.018). On multivariate analysis, early SRS and smaller tumor volumes were associated with better PFS, while younger age was associated with better survival. One patient had an adverse radiation effect after SRS. CONCLUSIONS: Stereotactic radiosurgery is an important adjuvant management strategy for residual tumors identified early after craniotomy and partial resection. Aggressive use of early boost radiosurgery following craniotomy and radiation therapy is recommended for patients with malignant meningiomas.