Faculty Bibliography

OBJECT: Trigeminal neuralgia pain causes severe disability. Stereotactic radiosurgery is the least invasive surgical option for patients with trigeminal neuralgia. Since different medical and surgical options have different rates of pain relief and morbidity, it is important to evaluate longer-term outcomes. METHODS: The authors retrospectively reviewed outcomes in 503 medically refractory patients with trigeminal neuralgia who underwent Gamma Knife surgery (GKS). The median patient age was 72 years (range 26-95 years). Prior surgery had failed in 205 patients (43%). The GKS typically was performed using MR imaging guidance, a single 4-mm isocenter, and a maximum dose of 80 Gy. RESULTS: Patients were evaluated for up to 16 years after GKS; 107 patients had > 5 years of follow-up. Eighty-nine percent of patients achieved initial pain relief that was adequate or better, with or without medications (Barrow Neurological Institute [BNI] Scores I-IIIb). Significant pain relief (BNI Scores I-IIIa) was achieved in 73% at 1 year, 65% at 2 years, and 41% at 5 years. Including Score IIIb (pain adequately controlled with medication), a BNI score of I-IIIb was found in 80% at 1 year, 71% at 3 years, 46% at 5 years, and 30% at 10 years. A faster initial pain response including adequate and some pain relief was seen in patients with trigeminal neuralgia without additional symptoms, patients without prior surgery, and patients with a pain duration of < or = 3 years. One hundred ninety-three (43%) of 450 patients who achieved initial pain relief reported some recurrent pain 3-144 months after initial relief (median 50 months). Factors associated with earlier pain recurrence that failed to maintain adequate or some pain relief were trigeminal neuralgia with additional symptoms and > or = 3 prior failed surgical procedures. Fifty-three patients (10.5%) developed new or increased subjective facial paresthesias or numbness and 1 developed deafferentation pain; these symptoms resolved in 17 patients. Those who developed sensory loss had better long-term pain control (78% at 5 years). CONCLUSIONS: Gamma Knife surgery proved to be safe and effective in the treatment of medically refractory trigeminal neuralgia and is of value for initial or recurrent pain management. Despite the goal of minimizing sensory loss with this procedure, some sensory loss may improve long-term outcomes. Pain relapse is amenable to additional GKS or another procedure.

OBJECTIVE: We define magnetic resonance imaging (MRI) and clinical criteria that differentiate radiation effect (RE) from tumor progression after stereotactic radiosurgery (SRS). METHODS: We correlated postoperative imaging and histopathological data in 68 patients who underwent delayed resection of a brain metastasis after SRS. Surgical resection was required in these patients because of clinical and imaging evidence of lesion progression 0.3 to 27.7 months after SRS. At the time of SRS, the median target volume was 7.1 mL (range, 0.5-26 mL), which increased to 14 mL (range, 1.3-81 mL) at the time of surgery. After initial SRS, routine contrast-enhanced MRI was used to assess tumor response and to detect potential adverse radiation effects. We retrospectively correlated these serial MRIs with the postoperative histopathology to determine if any routine MRI features might differentiate tumor progression from RE. RESULTS: The median time from SRS to surgical resection was 6.9 months (range, 0.3-27.7 months). A shorter interval from SRS to resection was associated with a higher rate of tumor recurrence (P = .014). A correspondence between the contrast-enhanced volume on T1-weighted images and the low signal-defined lesion margin on T2-weighted images ("T1/T2 match") was associated with tumor progression at histopathology (P < .0001). Lack of a clear and defined lesion margin on T2-weighted images compared to the margin of contrast uptake on T1-weighted images ("T1/T2 mismatch") was significantly associated with a higher rate of RE in pathological specimens (P < .0001). The sensitivity of the T1/T2 mismatch in identifying RE was 83.3%, and the specificity was 91.1%. CONCLUSIONS: We found that time to progression and T1/T2 mismatch were able to differentiate tumor progression from RE in most patients. When REs are suspected, surgery may not be necessary if patients respond to conservative measures. When tumor progression is suspected, resection or repeat radiosurgery can be effective, depending on the degree of mass effect.

PURPOSE: To determine the indication and outcomes for Gamma Knife stereotactic radiosurgery (GKSRS) in the care of patients with intracranial sarcomatous metastases. METHODS AND MATERIALS: Data from 21 patients who underwent radiosurgery for 60 sarcomatous intracranial metastases (54 parenchymal and 6 dural-based) were studied. Nine patients had radiosurgery for solitary tumors and 12 for multiple tumors. The primary pathology was metastatic leiomyosarcoma (4 patients), osteosarcoma (3 patients), soft-tissue sarcoma (5 patients), chondrosarcoma (2 patients), alveolar soft part sarcoma (2 patients), and rhabdomyosarcoma, Ewing's sarcoma, liposarcoma, neurofibrosarcoma, and synovial sarcoma (1 patient each). Twenty patients received multimodality management for their primary tumor, and 1 patient had no evidence of systemic disease. The mean tumor volume was 6.2 cm(3) (range, 0.07-40.9 cm(3)), and a median margin dose of 16 Gy was administered. Three patients had progressive intracranial disease despite fractionated whole-brain radiotherapy before SRS. RESULTS: A local tumor control rate of 88% was achieved (including patients receiving boost, up-front, and salvage SRS). New remote brain metastases developed in 7 patients (33%). The median survival after diagnosis of intracranial metastasis was 16 months, and the 1-year survival rate was 61%. CONCLUSIONS: Gamma Knife radiosurgery was a well-tolerated and initially effective therapy in the management of patients with sarcomatous intracranial metastases. However, many patients, including those who also received fractionated whole-brain radiotherapy, developed progressive new brain disease.

PURPOSE: To evaluate the outcome of repeat stereotactic radiosurgery (SRS) for acoustic neuromas, we assessed tumor control, clinical outcomes, and the risk of adverse radiation effects in patients whose tumors progressed after initial management. METHODS AND MATERIALS: During a 21-year experience at our center, 1,352 patients underwent SRS as management for their acoustic neuromas. We retrospectively identified 6 patients who underwent SRS twice for the same tumor. The median patient age was 47 years (range, 35-71 years). All patients had imaging evidence of tumor progression despite initial SRS. One patient also had incomplete surgical resection after initial SRS. All patients were deaf at the time of the second SRS. The median radiosurgery target volume at the time of the initial SRS was 0.5 cc and was 2.1 cc at the time of the second SRS. The median margin dose at the time of the initial SRS was 13 Gy and was 11 Gy at the time of the second SRS. The median interval between initial SRS and repeat SRS was 63 months (range, 25-169 months). RESULTS: At a median follow-up of 29 months after the second SRS (range, 13-71 months), tumor control or regression was achieved in all 6 patients. No patient developed symptomatic adverse radiation effects or new neurological symptoms after the second SRS. CONCLUSIONS: With this limited experience, we found that repeat SRS for a persistently enlarging acoustic neuroma can be performed safely and effectively.

Intracranial metastatic prostate carcinoma is rare. We sought to determine the clinical outcomes after Gamma Knife stereotactic radiosurgery (GKSRS) for patients with intracranial prostate carcinoma metastases. We studied data from 10 patients who underwent radiosurgery for 15 intracranial metastases (9 dural-based and 6 parenchymal). Six patients had radiosurgery for solitary tumors and four had multiple tumors. The primary pathology was adenocarcinoma (eight patients) and small cell carcinoma (two patients). All patients received multimodality management for their primary tumor (including resection, radiation therapy, androgen deprivation therapy) and eight patients had evidence of systemic disease at time of radiosurgery. The mean tumor volume was 7.7 cm(3) (range 1.1-17.2 cm(3)) and a median margin dose of 16 Gy was administered. Two patients had progressive intracranial disease in spite of fractionated partial brain radiation therapy (PBRT) prior to SRS. A local tumor control rate of 85% was achieved (including patients receiving boost, upfront and salvage SRS). New remote brain metastases developed in three patients (33%) and one patient had repeat SRS for tumor recurrence. The median survival after radiosurgery was 13 months and the 1-year survival rate was 60%. SRS was a well tolerated and effective therapy either alone or as a boost to fractionated radiation therapy in the management of patients with intracranial prostate carcinoma metastases.

OBJECTIVE: Patients with intracranial aneurysms, both ruptured and unruptured, are frequently eligible for both open surgery ("clipping") and endovascular repair ("coiling"). Although results of randomized trials have informed this decision, the actual choice of clipping or coiling for individual patients remains complex. At the 2007 Congress of Neurological Surgeons (CNS) Annual Meeting, a novel active learning process called Integrated Medical Learning (IML) was applied to education about this critical treatment choice. METHODS: CNS members received an electronically distributed premeeting survey and educational materials about the clipping versus coiling decision and related topics. At the Annual Meeting, participants used handheld devices to choose clipping or coiling for treatment of individual aneurysms, both before and after expert opinion presentations. After the meeting, members who had answered premeeting surveys received a follow-up questionnaire. RESULTS: In the premeeting poll, respondents with self-described specialties of "vascular," Cerebrovascular Section members, surgeons with active cerebrovascular practices, and surgeons in practice for less than 20 years had higher levels of baseline knowledge of cerebrovascular literature (P < .03). Surgeons' clinical volumes of clipping and coiling strongly influenced their vote for clipping or coiling for a hypothetical patient (P < .01). At the meeting, in 6 of 8 cases of ruptured aneurysms the audience was split 75%:25% or closer to "clinical equipoise" (50:50 split). Surgeons with vascular specialty, academic surgeons, and residents were more likely to recommend clipping for individual cases (P < .05). After experts' presentations, in 6 of 8 cases the audience opinion changed significantly. Vascular specialists and younger surgeons were less likely to change their opinion (P < .03). The 2 cases with no shift in opinion were the most-clippable and most-coilable cases. Postmeeting surveys showed evidence of retained knowledge from the meeting, and respondents thought IML had been helpful. CONCLUSIONS: Using IML, we were able to study baseline knowledge and practice patterns for an important cerebrovascular treatment decision. Evidence suggested that expert presentations were effective in changing audience opinion, at least in cases where preexisting opinion was close to clinical equipoise.

QUESTION: Do steroids improve neurologic symptoms in patients with metastatic brain tumors compared to no treatment? If steroids are given, what dose should be used? Comparisons include: (1) steroid therapy versus none. (2) comparison of different doses of steroid therapy. TARGET POPULATION: These recommendations apply to adults diagnosed with brain metastases. RECOMMENDATIONS: Steroid therapy versus no steroid therapy Asymptomatic brain metastases patients without mass effect Insufficient evidence exists to make a treatment recommendation for this clinical scenario. Brain metastases patients with mild symptoms related to mass effect Level 3 Corticosteroids are recommended to provide temporary symptomatic relief of symptoms related to increased intracranial pressure and edema secondary to brain metastases. It is recommended for patients who are symptomatic from metastatic disease to the brain that a starting dose of 4-8 mg/day of dexamethasone be considered. Brain metastases patients with moderate to severe symptoms related to mass effect Level 3 Corticosteroids are recommended to provide temporary symptomatic relief of symptoms related to increased intracranial pressure and edema secondary to brain metastases. If patients exhibit severe symptoms consistent with increased intracranial pressure, it is recommended that higher doses such as 16 mg/day or more be considered. Choice of Steroid Level 3 If corticosteroids are given, dexamethasone is the best drug choice given the available evidence. Duration of Corticosteroid Administration Level 3 Corticosteroids, if given, should be tapered slowly over a 2 week time period, or longer in symptomatic patients, based upon an individualized treatment regimen and a full understanding of the long-term sequelae of corticosteroid therapy. Given the very limited number of studies (two) which met the eligibility criteria for the systematic review, these are the only recommendations that can be offered based on this methodology. Please see "Discussion" and "Summary" section for additional details.

QUESTION: What evidence is available regarding the use of whole brain radiation therapy (WBRT), stereotactic radiosurgery (SRS), surgical resection or chemotherapy for the treatment of recurrent/progressive brain metastases? TARGET POPULATION: This recommendation applies to adults with recurrent/progressive brain metastases who have previously been treated with WBRT, surgical resection and/or radiosurgery. Recurrent/progressive brain metastases are defined as metastases that recur/progress anywhere in the brain (original and/or non-original sites) after initial therapy. RECOMMENDATION: Level 3 Since there is insufficient evidence to make definitive treatment recommendations in patients with recurrent/progressive brain metastases, treatment should be individualized based on a patient's functional status, extent of disease, volume/number of metastases, recurrence or progression at original versus non-original site, previous treatment and type of primary cancer, and enrollment in clinical trials is encouraged. In this context, the following can be recommended depending on a patient's specific condition: no further treatment (supportive care), re-irradiation (either WBRT and/or SRS), surgical excision or, to a lesser extent, chemotherapy. Question If WBRT is used in the setting of recurrent/progressive brain metastases, what impact does tumor histopathology have on treatment outcomes? No studies were identified that met the eligibility criteria for this question.