Postoperative Gamma Knife Radiosurgery Research Articles

Twelve-year experience of pineal region meningiomas: long-term outcomes of maximal safe resection.

The purpose of this research was to summarize the clinical and prognostic features of pineal region meningiomas, evaluate treatment strategies and long-term prognoses, and improve the management of pineal region meningiomas. We retrospectively studied the data of 37 patients who received surgical resection for pineal region meningiomas at West China Hospital of Sichuan University from 2009 to 2021. Adjuvant gamma knife radiosurgery (GKRS) was conducted according to the extent of resection (EOR). Progression-free survival (PFS), Karnofsky performance status (KPS) scores and recovery of neurological function were adopted to assess a comprehensive management strategy for pineal region meningiomas. The most common symptom was headache associated with intracranial hypertension (75.7%). The occipital transtentorial approach (40.5%) and supracerebellar infratentorial approach (29.7%) were performed in most cases. Gross total resection (GTR) was achieved in 27 patients (73.0%) and the remaining patients were treated with subtotal resection (STR) combined with postoperative GKRS. With a mean follow-up period of 87.0 months, the progression rate was 10.0%, the 5-year PFS rate was 92.9%, and the ΔKPS was 16.3. Multivariate analysis revealed that the STR + GKRS and supracerebellar infratentorial approach were beneficial to the recovery of quality of life of patients. Pineal region meningiomas are sporadic but challenging. It is necessary to select the most appropriate surgical approach, EOR, and hydrocephalus treatment strategy for patients with pineal region meningiomas. Maximal safe resection to protect neurovascular function combined with postoperative GKRS can significantly improve the quality of life of patients.

Transorbital neuroendoscopic surgery for treatment of sphenoid wing meningiomas extending to the cavernous sinus: clinical implications and a technical illustration.

The aim of this study was to evaluate the efficacy and safety of transorbital neuroendoscopic surgery (TONES) in the management of sphenoid wing meningiomas (SWMs) with cavernous sinus and orbital invasion. The authors conducted a retrospective review of 32 patients with SWMs treated at Gazi University using TONES from October 2019 to May 2023. The study includes clinical applications to elucidate the endoscopic transorbital approach. Surgical techniques focused on safe subtotal resection, aiming to minimize residual tumor volume for subsequent radiosurgery. Data were collected on patient demographics, tumor characteristics, surgical procedures, complications, and postoperative outcomes, including radiological imaging and ophthalmological evaluations. Surgical dissections delineated a three-phase endoscopic transorbital approach: extraorbital, intraorbital, and intracranial. In the clinical application, gross-total resection was not achieved in any patient because of planned postoperative Gamma Knife radiosurgery. The mean follow-up period was 16.3 months. Of 30 patients with preoperative proptosis, 25 experienced postoperative improvement. No new-onset extraocular muscle paresis or visual loss occurred postoperatively. The average hospital stay was 1.15 days, with minimal complications and no significant morbidity or mortality. Total resection of SWMs invading the cavernous sinus and orbit is associated with substantial risks, particularly cranial nerve deficits. TONES offers a minimally invasive alternative, reducing morbidity compared with transcranial approaches, and represents a significant advancement in the surgical management of SWMs, especially those extending into the cavernous sinus and orbit. The approach provides a safe, effective, and patient-centric approach, prioritizing subtotal resection to minimize neurological deficits while preparing patients for adjunctive radiosurgery. This study positions TONES as a transformative surgical technique, aligning therapeutic efficacy with neurovascular preservation and postoperative recovery.

Post-operative gamma knife radiosurgery for WHO grade I intracranial meningiomas: A single-center, retrospective study.

To explore the results of the Gamma Knife radiosurgery (GKRS) for World Health Organization (WHO) grade I intracranial meningiomas after surgical resection. A total of 130 patients who were pathologically diagnosed as having WHO grade I meningiomas and who underwent post-operative GKRS were retrospectively reviewed in a single center. Of the 130 patients, 51 patients (39.2%) presented with radiological tumor progression with a median follow-up time of 79.7 months (ranging from 24.0 to 291.3 months). The median time to radiological tumor progression was 73.4 months (ranging from 21.4 to 285.3 months), whereas 1-, 3-, 5-, and 10-year radiological progression-free survival (PFS) was 100, 90, 78, and 47%, respectively. Moreover, 36 patients (27.7%) presented with clinical tumor progression. Clinical PFS at 1, 3, 5, and 10 years was 96, 91, 84, and 67%, respectively. After GKRS, 25 patients (19.2%) developed adverse effects, including radiation-induced edema (n = 22). In a multivariate analysis, a tumor volume of ≥10 ml and falx/parasagittal/convexity/intraventricular location were significantly associated with radiological PFS [hazard ratio (HR) = 1.841, 95% confidence interval (CI) = 1.018-3.331, p = 0.044; HR = 1.761, 95% CI = 1.008-3.077, p = 0.047]. In a multivariate analysis, a tumor volume of ≥10 ml was associated with radiation-induced edema (HR = 2.418, 95% CI = 1.014-5.771, p = 0.047). Of patients who presented with radiological tumor progression, nine were diagnosed with malignant transformation. The median time to malignant transformation was 111.7 months (ranging from 35.0 to 177.2 months). Clinical PFS after repeat GKRS was 49 and 20% at 3 and 5 years, respectively. Secondary WHO grade II meningiomas were significantly associated with a shorter PFS (p = 0.026). Post-operative GKRS is a safe and effective treatment for WHO grade I intracranial meningiomas. Large tumor volume and falx/parasagittal/convexity/intraventricular location were associated with radiological tumor progression. Malignant transformation was one of the main cause of tumor progression in WHO grade I meningiomas after GKRS.

Stereotactic radiosurgery for post operative brain metastasic surgical cavities: a single institution experience.

BackgroundThe standard therapy for brain metastasis was surgery combined with whole brain radiotherapy (WBRT). The latter is however, associated with important neurocognitive toxicity. To reduce this toxicity, postoperative stereotactic radiosurgery (SRS) is a promising technique. We assessed the efficacy and the tolerance to postoperative Gamma Knife radiosurgery (GK) on the tumor bed after resection of brain metastases.MethodsBetween February 2011 and December 2016, following macroscopic complete surgical resection, 64 patients and 65 surgical cavities were treated by GK in our institution. The indication for adjuvant radiosurgery was a multidisciplinary decision. The main assessment criteria considered in this study were local control, intracranial metastasis-free survival (ICMFS), overall survival and toxicity.ResultsMedian follow-up: 11.1 months. Median time between surgery and radiosurgery: 35 days. Median dose was 20 Gy prescribed to the 50% isodose line, for a median treated volume of 5.6 cc. Four patients (7%) suffered from local recurrence. Local recurrence-free, intracranial recurrence-free and overall survival at 1 year were 97.5%, 57.6% and 62.4% respectively. In total, 23 patients (41%) suffered from intracranial recurrence outside the tumor bed. In univariate analysis: concomitant GK treatment of multiple lesions and the tumor bed was associated with a decrease in ICMFS (HR = 1.16 [1.005–1.34] p = 0.04). In multivariate analysis: a non-lung primary tumor was significantly associated with a decrease in ICMFS (HR = 8.04 [1.82–35.4] p = 0.006). An increase in performance status (PS) and in the initial number of cerebral metastases significantly reduced overall survival (HR = 5.4 [1.11–26.3] p = 0.037, HR = 2.7 [1.004–7.36] p = 0.049, respectively) and One radiation necrosis histologically proven.ConclusionOur study confirmed that postoperative GK after resection of cerebral metastases is an efficient and well-tolerated technique, to treat volumes of all sizes (0.8 to 40 cc). Iterative SRS or salvage WBRT can be performed in cases of intracranial relapse, postponing WBRT with its potential side effects.

Primary versus postoperative gamma knife radiosurgery for intracranial benign meningiomas: a matched cohort retrospective study

ObjectiveThe aims of this study were to investigate the long-term outcomes of primary versus postoperative Gamma Knife radiosurgery (GKRS) for benign meningiomas.MethodsThree hundred and forty meningioma patients underwent GKRS were retrospectively reviewed. Patients in the postoperative GKRS group were matched to those in the primary GKRS group, in a 1:1 ratio.ResultsThe study consisted of 122 patients, including primary (n = 61) and postoperative (n = 61) GKRS group. Thirty-four patients (27.9%) occurred radiological progression after a median follow-up of 72.5 (range, 24.2–254.5) months. The median time to radiological progression was 85.1 (range, 20.7–205.1) months. The radiological progression-free survival (PFS) was 100%, 93%, 87%, and 49%, at 1, 3, 5, and 10 years respectively. Thirty-one patients (25.4%) occurred clinical progression. The clinical PFS was 92%, 89%, 84%, and 60%, at 1, 3, 5, and 10 years. In combined group, only max diameter ≥ 50 mm was associated with radiological (p = 0.020) and clinical PFS (hazard ratio [HR] = 2.896, 95% confidence interval [CI] = 1.280–6.553, p = 0.011). Twenty-five patients (20.5%) developed GKRS related adverse effects, including radiation-induced edema (n = 21). Non-skull base tumors (HR = 3.611, 95% CI = 1.489–8.760, p = 0.005) and preexisting peritumoral edema (HR = 3.571, 95% CI = 1.167–10.929, p = 0.026) were significantly related to radiation-induced edema in combined group. There was no significant difference in radiological PFS (p = 0.403), clinical PFS (p = 0.336), and GKRS related adverse effects (p = 0.138) between primary and postoperative GKRS groups.ConclusionsPrimary GKRS could provide similar radiological and clinical outcomes, as well as similar complication rate compared with postoperative GKRS. For selective benign meningioma patients (asymptomatic or mildly symptomatic tumors; unfavorable locations for surgical resection; comorbidities or an advanced age), GKRS could be an alternative primary treatment.

Endoscopic Transnasal Resection of Trigeminal Schwannoma.

Trigeminal schwannoma is a rare skull base tumor that can be managed in a variety of treatments including image observation, surgery, stereotactic radiosurgery, such as gamma knife radiosurgery (GKS), and combination of these. Endoscopic transnasal resection is very effective when the tumor is not invading far laterally, or the risk of cerebrospinal fluid (CSF) leak is estimated to be low. A 74-year-old man with a history of prostate cancer and diabetes presented with left oculomotor nerve palsy over a month. Magnetic resonance images (MRI) demonstrated a 25-mm mass in the left cavernous sinus protruding to the left orbit via the superior orbital fissure ( Fig. 1 ). The patient underwent endoscopic transnasal surgery to decompress the mass. The surgery was uneventful, and postoperative MRI demonstrated satisfactory subtotal resection of the mass ( Fig. 2 ). The final pathology returned as schwannoma. At 1-year follow-up, the tumor slowly enlarged, and the patient underwent GKS with a marginal dose of 14 Gy. At the last follow-up, 4 months after GKS, the tumor was stable. Unfortunately the patient deceased from the known prostate cancer. Endoscopic transnasal surgery was especially useful in this case, considering the preoperative known cancer state that management of this benign tumor did not ruin the quality of life of this patient while minimizing hospitalization, as achieving satisfactory tumor control with aid from postoperative GKS, minimizing complications. The link to the video can be found at: https://youtu.be/Q0Ugc2VFV4w .

Long-term outcome in meningiomas involving the major dural sinuses with combined therapy of subtotal resection and early postoperative gamma knife radiosurgery.

Total resection of meningiomas involving the major dural sinuses (MIMDS) is still challenging for neurosurgeons. Gamma knife radiosurgery (GKRS) was shown to have a high probability of tumor control. The current study evaluated the clinical outcomes of patients who underwent subtotal resection alone or in combination with postoperative GKRS for the treatment of WHO grade I MIMDS. From January 2006 to December 2016, 204 patients with MIMDS underwent Simpson IV subtotal resection in Wuhan Union Hospital. In 151 patients, no additional treatment was performed, while the tumor remnant was treated with GKRS in 53 patients. All patients were monitored with regular MR follow-ups. We retrospectively reviewed the clinical data, radiological characteristics, and outcomes of these 204 patients. Progression-free survival (PFS) was determined by Kaplan-Meier analysis. Related factors were determined by univariate Cox regression analyses. The mean follow-up period was 75.5 months. The tumor recurrence/progression rates were 13.9% in the microsurgery group and 3.8% in the combined therapy group (p = 0.045). The 5- and 10- year progression-free survival (PFS) rates were 92.3 and 80.7%, respectively, in the microsurgery group and 100.0 and 88.5% in the combined therapy group. Treatment approach was found to be an independent prognostic factor for tumor recurrence/progression in the univariable analyses (p=0.04). Compared with microsurgery alone, targeted Simpson grade IV resection combined with early gamma knife treatment resulted in longer progression-free survival without increased complications for WHO grade I MIMDS.

Comparing primary gamma knife radiosurgery and postoperative gamma knife radiosurgery for acromegaly: A monocenter retrospective study

ObjectiveTo compare the efficacy and safety between primary GKS and postoperative GKS for acromegaly, and to elucidate predictors associated with endocrine remission, we performed a monocenter, retrospective study. MethodSeventy-five patients with acromegaly who had received GKS in West China Hospital between March 2010 and December 2018 were included in this study. Endocrine remission was defined as age-sex matched IGF-I normalization and either nadir level of GH <1 ng/mL after OGTT or the random GH < 2.0 ng/mL. ResultsWe didn’t find significant differences in endocrine remission, biochemical recurrence, imaging regression, imaging progression, radiation-induced complications between the primary GKS group and the postoperative GKS group(P > 0.05). Actuarial rates of durable endocrine remission at 3, 5, 8 year were 10.60 %, 33.80 % and 70.60 % in the primary GKS group and 6.70 %, 43.40 % and 78.80 % in the postoperative GKS group(P = 0.800). Only base nadir GH after OGTT (HR = 0.637,95 % CI:0.416−0.977; P = 0.039) was found to be a predictor of duration endocrine remission. ConclusionWe find comparable efficacy and safety between primary GKS and postoperative GKS. Lower base nadir GH after OGTT was a positive predictor associated with endocrine remission. GKS should be considered for residual or recurrent tumor after surgery. For those who couldn’t sustain surgery, GKS is an alternative treatment. Further studies are required to elucidate the efficacy and safety of GKS in acromegaly.

Risk of Leptomeningeal Carcinomatosis after Post-Operative Gamma Knife Radiosurgery for Resected Brain Metastases

Risk of Leptomeningeal Carcinomatosis after Post-Operative Gamma Knife Radiosurgery for Resected Brain Metastases

Postoperative Gamma Knife Radiosurgery for Cavernous Sinus-Invading Growth Hormone-Secreting Pituitary Adenomas.

We aimed to determine the long-term effects of Gamma knife radiosurgery (GKS) on remnants in the cavernous sinus (CS) after transsphenoidal surgery (TSS) for acromegaly and to identify its possible adverse effects. Thirty patients who had remnant tumors only inside the CS after TSS and who consequently underwent GKS were included. They were followed for a median period of 47 months after GKS with regular hormonal and radiologic examinations. The mean tumor volume and margin dose irradiated by GKS was 3.7 cm3 and 26.2 Gy, respectively. Radiologic tumor control was identified in all patients, and no tumor regrowth or recurrent tumors were identified. For 14 patients who achieved endocrinologic remission, the median duration from GKS until remission was 35 months. The actuarial rates of remission at 2, 5, and 10 years were 7.1%, 43.6%, and 65.6%, respectively. The degree of decrease in the nadir GH level in the OGTT at 6 months after GKS was a statistically significant predictor of remission. Newly developed hypopituitarism frequently developed in a time-dependent manner. Radiation necrosis developed in 4 patients with relatively large remnant volumes. GKS is an effective adjuvant treatment option for remnant tumors inside the CS after TSS. Maximal surgical resection, leaving minimal volume of remnants only inside the CS, allows the safe and sufficient delivery of a radiation dose to tumors, thereby increasing the possibility of remission. However, the risk of new hypopituitarism and radiation necrosis should be considered when tumors inside the CS are treated with GKS.

Gamma Knife Radiosurgery for Atypical and Anaplastic Meningiomas

Atypical and anaplastic meningiomas have much higher recurrence rates after surgical resection compared with benign meningiomas, but the role of adjuvant radiosurgery remains unclear. This study was undertaken to evaluate the outcomes of gamma knife radiosurgery for patients with atypical and anaplastic meningiomas. In this retrospective analysis of a prospectively maintained database, 46 patients with histologically proven atypical or anaplastic meningiomas by current World Health Organization (WHO) criteria underwent postoperative Gamma Knife radiosurgery between 1993 and 2013. The median follow-up period was 32.6 months. The median tumor volume and margin dose were 11.7 mL (range, 2-53 mL) and 13.1 Gy (range, 12.0-16.5 Gy), respectively. Local control at 3 and 5 years was 50.6% and 32.1%, respectively. Gender (P = 0.013) and marginal dose less than or equal to 13 Gy (P = 0.049) were associated with the local control. The 3- and 5-year overall survival for patients with WHO grade II was 97.1% and 88.3%, respectively, compared with 66.7% and 66.7% for patients with WHO grade III meningiomas. Radiation therapy before Gamma Knife radiosurgery (GKRS; P = 0.018) and tumor grade (P = 0.019) were the factors associated with a worse overall survival rate. Fourteen patients (30.4%) developed adverse radiation effects after GKRS treatment, and all were Radiation Therapy Oncology Group grade I. Postoperative GKRS treatment for patients with atypical and anaplastic meningioma is challenging. More aggressive treatment, including of safely maximizing the extent of surgical resection and using a higher margin dose (>13Gy), should be applied to achieve better local control.

Effectiveness of Postoperative Gamma Knife Radiosurgery to the Tumor Bed After Resection of Brain Metastases

The role of Gamma knife radiosurgery (GKS) after the resection of brain metastases remains undefined. We evaluated the outcomes of postoperative GKS to the tumor bed after the resection of brain metastasis compared with GKS alone without resection in the same patients. We performed a retrospective review of 24 patients who underwent GKS to the tumor bed after the resection of brain metastases. In this cohort, 25 metastatic lesions were treated with postoperative GKS, and 37 brain metastatic lesions were simultaneously managed with GKS alone without resection. The median target volume and marginal dose of GKS to the surgical bed were 10.5 cm(3) and 15.0 Gy, respectively. The median target volume and marginal dose of GKS alone for the metastatic lesions were 0.5 cm(3) and 21.0 Gy, respectively. The actuarial 1-year and 2-year overall survival of the patients were 43.1% and 28.7%, respectively. The median overall survival of all patients was 11 months. The actuarial 6-month and 12-month local progression-free survival of GKS alone for metastatic lesions without resection were 92.6% and 84.9%; however, the actuarial 6-month and 12-month local progression-free survival of GKS to the surgical bed were 82% and 71%, respectively. For patients with brain metastases treated with surgical resection, postoperative GKS to the resection area is an effective and safe treatment option. Particularly, concurrent postoperative GKS to the surgical cavity with GKS alone for multiple small metastatic lesions is a feasible treatment strategy for multiple brain metastases.

Cerebellar glioblastoma multiforme: a retrospective study of 28 patients at a single institution

Cerebellar glioblastoma multiforme (CGBM) is rare and its treatment is ill defined. To elucidate prognostic factors, we performed a single institutional review of the largest series to date of CGBM. The West China Hospital database was reviewed from 2007 to June 2011, and a total of 28 CGBM patients were collected. Median age of patients was 50 years old, whereas median Karnofsky Performance Status was 80 (range, 30–100). Brainstem invasion was observed in 9 patients. Sixteen patients received total resection and 12 patients received subtotal resection. Postoperative Gamma Knife radiosurgery (GKRS) was administered to 22 patients. After operation, 16 patients received concurrent GKRS and chemotherapy, and 6 patients received chemotherapy after GKRS. In addition, 4 patients only received chemotherapy, and 2 patients did not receive either GKRS or chemotherapy due to various reasons. Median follow-up period was 13.7 months (range, 5.2–28.1 months). Median overall survival (OS) of 28 patients was 14.3 months and median progression-free survival (PFS) was 9.4 months. Univariate log-rank analysis showed that OS and PFS were significantly related to brainstem invasion (p = 0.03, p = 0.04, respectively), extent of resection (p = 0.02, p = 0.04, respectively) and GKRS (p = 0.01, p = 0.02, respectively) of GBM. Multivariate analysis revealed that OS and PFS were also significantly associated with brainstem invasion (p = 0.007, p = 0.014, respectively), extent of resection (p = 0.032, p = 0.045, respectively) and GKRS (p = 0.031, p = 0.046, respectively) of CGBM. According to our study, brainstem invasion, extent of resection and GKRS were major prognostic factors for survival. Combination of postoperative GKRS and chemotherapy had an improved prognosis, and it may be a feasible postoperative adjuvant treatment of CGBM.

Prospective trial of gross-total resection with Gliadel wafers followed by early postoperative Gamma Knife radiosurgery and conformal fractionated radiotherapy as the initial treatment for patients with radiographically suspected, newly diagnosed glioblastoma multiforme

The purpose of this study was to determine whether increased local control and improved survival can be achieved in patients with glioblastoma multiformes (GBMs) who undergo aggressive resection, Gliadel wafer implantation, Gamma Knife radiosurgery (GKS), and fractionated radiotherapy (RT) as the initial treatment. Thirty patients with radiographically suspected GBMs were screened for enrollment in a Phase I/II prospective clinical trial. Twenty-seven patients were eligible and underwent gross-total resection and Gliadel wafer implantation. Gamma Knife radiosurgery (12 Gy at 50%) was administered to the resection cavity within 2 weeks of surgery. Patients then received standard fractionated RT (total dose 60 Gy over 6 weeks). Temozolomide was prescribed for patients at the time of recurrence. Surveillance MR imaging, neurological examination, and quality-of-life evaluations were performed at 2-month intervals. To estimate the potential effects on the DNA repair mechanism, tumor tissue was analyzed with methylation-specific polymerase chain reaction analysis and immunohistochemical assays for MGMT gene promoter methylation and protein expression. The median survival for all patients was 50 weeks and the 2-year survival rate was 22%. When stratified into standard and high-risk patient groups, the median survivals were 76 and 33 weeks, respectively. Two patients remain alive at the time of this report with no clinical or radiographic evidence of disease at > 189 and 239 weeks posttreatment and excellent performance status. Local tumor control was achieved in 53% of patients, and local failure occurred in 47%. No acute early toxicity was noted; however, delayed symptomatic radionecrosis occurred in 47% of patients, which required repeated operations 9-24 months after the initial treatment. Delayed hydrocephalus requiring ventriculoperitoneal shunt placement occurred in 47% of patients. There was a significant difference in survival between patients whose tumors contained the methylated and unmethylated MGMT promoter, 103 versus 45 weeks, respectively (p = 0.0009, log-rank test). The combination of aggressive resection, Gliadel wafer implantation, and GKS in addition to standard fractionated RT in selected patients resulted in increased local control and increased survival compared with a historical control group treated with surgery and involved-field RT alone. Delayed focal radionecrosis was increased to 47% in this series and was managed with steroids and repeated resection. Aggressive local tumor control with these multimodal therapies should be approached judiciously for a select group of high performance patients and the probability of developing symptomatic radionecrosis requiring surgery should be anticipated and fully disclosed to patients who undergo this treatment.

Treatment of Glomus Jugulare Tumors in Patients with Advanced Age: Planned Limited Surgical Resection Followed by Staged Gamma Knife Radiosurgery: A Preliminary Report

To minimize treatment comorbidities in glomus jugulare tumor patients with advanced age while reducing pulsatile tinnitus and preserving or improving residual hearing using a limited middle ear/mastoid tumor resection and postoperative gamma knife radiosurgery to tumor remnants in the jugular foramen region. Retrospective consecutive case review of five patients. Tertiary referral, academic medical center. Patients with advanced age (mean, 69.6 yr; range, 61-78 yr) harboring symptomatic glomus jugulare tumors. All patients were treated with resection of middle ear and mastoid portions of tumor and subsequent gamma knife radiosurgery to jugular foramen portion of tumor. Length of hospitalization; hearing, pulsatile tinnitus, cranial nerve, and tumor control status. All patients were treated on an outpatient surgical basis without the need for blood transfusion. There were no incidents of a change in cranial nerve status (Cranial Nerves VII, IX, X, XI, and XII) in the immediate postoperative period. All patients had improvement or resolution of pulsatile tinnitus with preservation or improvement of preoperative hearing levels. Tumor volume was stable or reduced in all patients at mean follow-up of 19 months (range, 11-24 mo). Gamma knife radiosurgery (mean peripheral dose of 15 Gy) was not associated with any significant immediate or delayed complications. Short-term data reveals that staged microsurgical and radiosurgical therapy for glomus jugulare tumors in the symptomatic patient with advanced age is safe and yields favorable results regarding tinnitus, hearing, and cranial nerve status. Long-term data are needed to further evaluate the effectiveness of this treatment algorithm before extrapolating this treatment option to younger patients.

Efficacy of gamma knife radiosurgery for nonfunctioning pituitary adenomas: a quantitative follow up with magnetic resonance imaging—based volumetric analysis

Object. The authors assessed the efficacy of gamma knife radiosurgery (GKS) for nonfunctioning pituitary adenomas (NPAs) by sequential quantitative determinations of tumor volume and neurological and endocrinological follow-up examinations. Methods. Through May of 2000, 45 patients with NPA were treated by GKS. Complete neurological and endocrinological follow-up information was obtained. In 30 patients (67%), follow-up examinations included stereotactic magnetic resonance imaging involving the GammaPlan software for sequential measurements of the NPA volume. These patients constitute the basis of this study. Sequential volume measurements after GKS were compared with initial tumor volumes at the date of GKS to quantify the therapeutic result. All data were stored prospectively in a computerized database. The median dose to the tumor margin was 16 Gy (range 11–20 Gy). The mean prescription isodose was 55% (range 45–75%). All except one patient (97%) underwent surgery for NPA before GKS. Fractionated radiotherapy was not administered. Median follow up after GKS was 55 months (range 28–86 months). The actuarial long-term recurrence-free survival was 93% with respect to a single GKS and 100% if a repeated GKS was included. Neurological side effects were not detected. The actuarial risk of radiosurgery-induced pituitary damage was calculated to be 14% after 6 years. The volumetric analysis revealed a temporary swelling of the NPA in four patients, followed by shrinkage of the lesion. This is the first time this has been observed in pituitary adenomas. Conclusions. Postoperative GKS for residual or recurrent small fragments of NPAs is effective and safe. With regard to the issues of radioprotection and therapeutic morbidity, it seems superior to fractionated radiotherapy. Quantification of tumor reduction is a valuable tool for documenting a therapeutic response and for identifying tumor recurrence. As part of a radiosurgical standard protocol, the follow-up examination for NPAs should include tumor volumetric analysis.

Surgical treatment of falcotentorial meningioma

Meningiomas arising from the falcotentorial junction are rare. Among our surgical experience of 375 meningiomas, only 4 cases of so-called falcotentorial meningiomas were encountered. We present these four surgical cases. An occipital transtentorial app roach was used in three cases, and a combined midline occipital and suboccipital approach in one case. Total tumour excision was impossible in two cases because of engulfing deep venous structures including the great vein of Galen. Postoperative Gamma knife radiosurgery was performed in these two cases. On the other hand, a posteriorly located tumour was relatively easy to remove, and macroscopic total removal was accomplished. In conclusion, precise microvascular anatomical knowledge is indispensable t o satisfactorily excise meningiomas in the falcotentorial area without significant morbidity.