Leksell Top 25 - Meningioma
Georgios Zenonos, Douglas Kondziolka, John C. Flickinger, Paul Gardner, and L. Dade Lunsford
Microsurgical management of foramen magnum meningiomas (FMMs) can be associated with significant morbidity and mortality. Stereotactic radiosurgery may be an efficient and safe alternative treatment modality for such tumors. The object of this study was to increase the documented experience with Gamma Knife surgery (GKS) for FMMs and to delineate its role in an overall management paradigm.
The authors report on their experience with 24 patients harboring FMMs managed with GKS. Twelve patients had primary symptomatic tumors, 5 had asymptomatic but enlarging primary tumors, and 7 had recurrent or residual tumors after a prior surgery.
Follow-up clinical and imaging data were available in 21 patients at a median follow-up of 47 months (range 3–128 months). Ten patients had measurable tumor regression, which was defined as an overall volume reduction > 25%. Eleven patients had no further tumor growth. Two patients died as a result of advanced comorbidities before follow-up imaging. One patient was living 8 years after GKS but had no clinical evaluation. Ten of 17 symptomatic patients with at least 6 months of follow-up had symptom improvement, and 7 remained clinically stable. Smaller tumors were more likely to regress. No patient suffered an adverse radiation effect after radiosurgery.
Gamma Knife surgery was a safe management strategy for small, minimally symptomatic, or growing FMMs as well as for residual tumors following conservative microsurgical removal.
Thomas J. Flannery, Hideyuki Kano, L. Dade Lunsford, Sait Sirin, Matthew Tormenti, Ajay Niranjan, John C. Flickinger, and Douglas Kondziolka
Because of their critical location adjacent to brain, cranial nerve, and vascular structures, petroclival meningiomas remain a clinical challenge. The authors evaluated outcomes in 168 patients with petroclival meningiomas who underwent Gamma Knife surgery (GKS) during a 21-year interval.
Gamma Knife surgery was used as either primary or adjuvant treatment of 168 petroclival meningiomas involving the region between the petrous apex and the upper two-thirds of the clivus. The most common presenting symptoms were trigeminal nerve dysfunction, balance problems, diplopia, and hearing loss. The median tumor volume was 6.1 cm3 (range 0.3–32.5 cm3), and the median radiation dose to the tumor margin was 13 Gy (range 9–18 Gy).
During a median follow-up of 72 months, neurological status improved in 44 patients (26%), remained stable in 98 (58%), and worsened in 26 (15%). Tumor volume decreased in 78 patients (46%), remained stable in 74 (44%), and increased in 16 (10%), all of whom were subjected to additional management strategies. Overall 5- and 10-year progression-free survival rates were 91 and 86%, respectively. Patients followed up for at least 10 years (31 patients) had tumor and symptom control rates of 97 and 94%, respectively. Eight patients had repeat radiosurgery, 4 underwent delayed resection, and 4 had fractionated radiation therapy. Cerebrospinal fluid diversion was performed in 7 patients (4%). Significant risk factors for tumor progression were a tumor volume ≥ 8 cm3 (p = 0.001) and male sex (p = 0.02).
In this 21-year experience, GKS for petroclival meningiomas obviated initial or further resection in 98% of patients and was associated with a low risk of adverse radiation effects. The authors believe that radiosurgery should be considered as an initial option for patients with smaller-volume, symptomatic petroclival meningiomas.
Douglas Kondziolka, Ricky Madhok, L. Dade Lunsford, David Mathieu, Juan J. Martin, Ajay Niranjan, and John C. Flickinger
Meningiomas of the cerebral convexity are often surgically curable because both the mass and involved dura mater can be removed. Stereotactic radiosurgery has become an important primary or adjuvant treatment for patients with intracranial meningiomas. The authors evaluated clinical and imaging outcomes in patients with convexity meningiomas after radiosurgery.
The patient cohort consisted of 125 patients with convexity meningiomas managed using radiosurgery at some point during an 18-year period. The patient series included 76 women, 55 patients who had undergone prior resection, and 6 patients with neurofibromatosis Type 2. Tumors were located in frontal (80 patients), parietal (24 patients), temporal (12 patients), and occipital (9 patients) areas. The WHO tumor grades in patients with prior resections were Grade I in 34 patients, Grade II in 15 patients, and Grade III in 6 patients. Seventy patients underwent primary radiosurgery and therefore had no prior histological tumor diagnosis. The mean tumor volume was 7.6 ml. Radiosurgery was performed using the Leksell Gamma Knife with a mean tumor margin dose of 14.2 Gy.
Serial imaging was evaluated in 115 patients (92%). After primary radiosurgery, the tumor control rate was 92%. After adjuvant radiosurgery, the control rate was 97% for Grade I tumors. The actuarial tumor control rates at 3 and 5 years for the entire series were 86.1 ± 3.8% and 71.6 ± 8.6%, respectively. For patients with benign tumors (Grade I) and those without prior surgery, the actuarial tumor control rate was 95.3 ± 2.3% and 85.8 ± 9.3%, respectively. Delayed resection after radiosurgery was performed in 9 patients (7%) at an average of 35 months. No patient developed a subsequent radiation-induced tumor. The overall morbidity rate was 9.6%. Symptomatic peritumoral imaging changes compatible with edema or adverse radiation effects developed in 5%, at a mean of 8 months.
Stereotactic radiosurgery provides satisfactory control rates either after resection or as an alternate to resection, particularly for histologically benign meningiomas. Its role is most valuable for patients whose tumors affect critical neurological regions and who are poor candidates for resection. Both temporary and permanent morbidity are related to brain location and tumor volume.
John Y. K. Lee, Ajay Niranjan, James McInerney, Douglas Kondziolka, John C. Flickinger, and L. Dade Lunsford
Object. To evaluate long-term outcomes of patients who have undergone stereotactic radiosurgery for cavernous sinus meningiomas, the authors retrospectively reviewed their 14-year experience with these cases.
Methods. One hundred seventy-six patients harbored meningiomas centered within the cavernous sinus. Seventeen patients were lost to follow-up review, leaving 159 analyzable patients, in whom 164 procedures were performed. Seventy-six patients (48%) underwent adjuvant radiosurgery after one or more attempts at surgical resection. Eighty-three patients (52%) underwent primary radiosurgery. Two patients (1%) had previously received fractionated external-beam radiation therapy. Four patients (2%) harbored histologically verified atypical or malignant meningiomas. Conformal multiple isocenter gamma knife surgery was performed. The median dose applied to the tumor margin was 13 Gy.
Neurological status improved in 46 patients (29%), remained stable in 99 (62%), and eventually worsened in 14 (9%). Adverse effects of radiation occurred after 11 procedures (6.7%). Tumor volumes decreased in 54 patients (34%), remained stable in 96 (60%), and increased in nine (6%). The actuarial tumor control rate for patients with typical meningiomas was 93.1 ± 3.3% at both 5 and 10 years. For the 83 patients who underwent radiosurgery as their sole treatment, the actuarial tumor control rate at 5 years was 96.9 ± 3%.
Conclusions. Stereotactic radiosurgery provided safe and effective management of cavernous sinus meningiomas. We believe it is the preferred management strategy for tumors of suitable volume (average tumor diameter ≤ 3 cm or volume ≤ 15 cm3).
Douglas Kondziolka, L. Dade Lunsford, Robert J. Coffey, and John C. Flickinger
✓ Stereotactic radiosurgery has an expanding role in the management of selected intracranial tumors. In an initial 30-month experience using the 201-source cobalt-60 gamma knife at the University of Pittsburgh, 50 patients with meningiomas were treated. The most frequent site of origin was the skull base. Previously, 36 patients (72%) had undergone at least one craniotomy and four patients (8%) had received fractionated external beam radiation therapy. Stereotactic radiosurgery was the primary treatment modality in 16 patients (32%) with symptomatic tumors demonstrated by neuroimaging. Computer imaging-generated isodose plans (with one to five irradiation isocenters) for single-treatment irradiation gave optimal (≥ 50% isodose line) coverage in 44 patients (88%). The proximity of cranial nerves or vascular, pituitary, and brain-stem structures to the often convoluted tumor mass was crucial to dose selection. Serial imaging studies were evaluated in all 50 patients. Twenty-four patients were examined between 12 and 36 months after treatment; 13 (54%) showed a reduction in tumor volume while nine (38%) showed no change. Of 26 patients evaluated between 6 and 12 months after treatment, four showed a decrease in tumor size while 22 showed no change. Two patients (both with large tumors that received suboptimal irradiation) had delayed tumor growth outside the radiosurgical treatment volume. The actuarial 2-year tumor growth control rate was 96%. Between 3 and 12 months after radiosurgery, three patients developed delayed neurological deficits that gradually improved, compatible with delayed radiation injury. Although extended follow-up monitoring over many years will be necessary to fully evaluate treatment, to date stereotactic radiosurgery has proved to be a relatively safe and effective therapy for selected patients with symptomatic meningiomas, including those who failed surgical resection. Radiosurgery was an effective primary treatment alternative for those patients whose advanced age, medical condition, or high-risk tumor location mitigated against surgical resection.