Efficacy of external fractionated radiation therapy in the treatment of meningiomas: a 20-year experience

Long-term outcomes of fractionated proton beam therapy for benign or radiographic intracranial meningioma

PURPOSE

Benign intracranial meningioma is one of the most common primary brain neoplasms. Proton therapy has been increasingly utilized for nonoperative management of this neoplasm, yet few long-term outcomes studies exist.

METHODS

The medical records of a total of 59 patients with 64 lesions were reviewed under a prospective outcomes tracking protocol for histologically proven or radiographically benign meningioma. The patients were treated with proton therapy at the University of Florida Proton Therapy Institute between 2007 and 2019 and given a median dose of 50.4 GyRBE at 1.8 GyRBE (relative biological effectiveness) (range 48.6-61.2 GyRBE) in once-daily treatments.

RESULTS

With a median clinical and imaging follow-up of 6.3 and 4.7 years, the rates of 5-year actuarial local progression and cumulative incidence of grade 3 or greater toxicity were 6% (95% confidence interval [CI] 1%-14%), and 2% (95% CI < 1%-15%), respectively. Two patients experienced local progression after 5 years. The 5-year actuarial overall survival rate was 87% (95% CI 74-94%).

CONCLUSION

Fractionated PBT up to 50.4 GyRBE is a safe and highly effective therapy for treating benign intracranial meningioma.

Survival Benefit of Prognostic Factors and Treatment in Adult Patients with Recurrent Anaplastic Meningioma: A Retrospective Case Series and Systematic Literature Review

BACKGROUND

Recurrence rates of anaplastic meningioma (AM) are high even after a complete resection with postoperative radiotherapy.

OBJECTIVE

This study aimed to evaluate predictors and treatment affecting survival of recurrent AM based on our series and a systematic literature review (SLR).

METHODS

Our single-institute (SI) data enrolled patients with first recurrent AM, treated in our hospital from 2012 to 2018. We retrieved eligible cases from SLR from 1966 to 2020. Our SI data and pooled data, integrating SI and SLR data, were subject to Cox proportional hazard regression analysis.

RESULTS

Analysis from SI data (n = 38) showed that second recurrence-free survival (RFS) was associated with intervals (HR [hazard ratio], 0.263; P = 0.002), preoperative Karnofsky Performance Status (KPS) (HR, 0.450; P = 0.043), radiotherapy (HR, 0.395; P = 0.047), whereas overall survival (OS) was related to preoperative KPS (HR, 0.411; P = 0.037) and tumor size (HR, 3.429; P = 0.007). The pooled data (n = 60) indicated that short intervals (HR, 0.370; P = 0.002) and the use of radiotherapy (HR, 0.318; P = 0.003) improved second RFS and number of resections ≥3 (HR, 0.210; P = 0.002) and radiotherapy (HR, 0.209; P = 0.002) prolonged OS. Furthermore, the overall second RFS (P = 0.024) and OS (P = 0.031) stratified by 4 treatment protocols differed significantly.

CONCLUSIONS

Early managements of patients with AM, before presence of poor preoperative KPS and large tumor size, are critical for survival. For patients with recurrent AM, survival benefits could be obtained from radiotherapy and multiple resections.

Regrowth factors of WHO grade I skull base meningiomas following incomplete resection

OBJECTIVE

The role of adjuvant radiation therapy following incomplete resection of WHO grade I skull base meningiomas (SBMs) is controversial, and little is known regarding the behavior of residual tumors. The authors investigated the factors that influence regrowth of residual WHO grade I SBMs following incomplete resection.

METHODS

From 2005 to 2019, a total of 710 patients underwent surgery for newly diagnosed WHO grade I SBMs. The data of 115 patients (16.2%) with incomplete resection and without any adjuvant radiotherapy were retrospectively assessed during a mean follow-up of 78 months (range 27-198 months). Pre-, intra-, and postoperative clinical and molecular factors were analyzed for relevance to regrowth-free survival (RFS).

RESULTS

Eighty patients were eligible for analysis, excluding those who were lost to follow-up (n = 10) or had adjuvant radiotherapy (n = 25). Regrowth occurred in 39 patients (48.7%), with a mean RFS of 50 months (range 3-191 months). Significant predictors of regrowth were Ki-67 proliferative index (PI) ≥ 4% (p = 0.017), Simpson resection grades IV and V (p = 0.005), and invasion of the cavernous sinus (p = 0.027) and Meckel's cave (p = 0.027). After Cox regression analysis, only Ki-67 PI ≥ 4% (hazard ratio [HR] 9.39, p = 0.003) and Simpson grades IV and V (HR 8.65, p = 0.001) showed significant deterioration of RFS. When stratified into 4 scoring groups, the mean RFSs were 110, 70, 38, and 9 months for scores 1 (Ki-67 PI < 4% and Simpson grade III), 2 (Ki-67 PI < 4% and Simpson grades IV and V), 3 (Ki-67 PI ≥ 4% and Simpson grade III), and 4 (Ki-67 PI ≥ 4% and Simpson grades IV and V), respectively. RFS was significantly longer for score 1 versus scores 2-4 (p < 0.01). Tumor consistency, histology, location, peritumoral edema, vascular encasement, and telomerase reverse transcriptase promoter mutation had no impact on regrowth.

CONCLUSIONS

Ki-67 PI and Simpson resection grade showed significant associations with RFS for WHO grade I SBMs following incomplete resection. Ki-67 PI and Simpson resection grade could be utilized to stratify the level of risk for regrowth.

Adjuvant Radiotherapy Did Not Reduce Recurrence of World Health Organization Grade I Meningiomas with Venous Sinus Involvement: A Propensity Score Adjusted Analysis and Literature Review

BACKGROUND

Most meningiomas are classified as World Health Organization (WHO) grade I. Adjuvant radiation therapy (RT) is commonly recommended for subtotal resections with documented progressive regrowth of lesions with venous sinus involvement. We investigated if recurrence of WHO grade I meningiomas was influenced by adjuvant RT.

METHODS

From 2000 to 2014, patients with grade I meningiomas with at least one venous sinus involvement and at least 4 years of follow-up were included. Demographics, venous sinus involvement, histology, and extent of resection (EOR) were characterized. Because patients undergoing RT tend to differ from those for whom adjuvant therapy was not prescribed, we used propensity scores to adjust for confounding variables.

RESULTS

Sixty-two patients were included; of these, 18 (29.0%) had recurrences. The mean age was 52.8 ± 12.3 years, and 79.0% were women. A total of 34 cases (54.8%) were submitted to adjuvant RT. Adjuvant RT was more frequent in those who had tumor recurrence (77.8% vs. 45.5%, P = 0.020). RT was more frequent in superior sagittal sinus (SSS) invasion (76.5% vs. 50.0%, P = 0.030) and less prevalent after gross total resection (GTR) (32.4% vs. 67.9%, P = 0.005). Propensity score adjusted analysis suggested no adjuvant RT benefit (odds ratio [OR], 2.51; 95% confidence interval [CI], 0.68-9.28; P = 0.167), independent of the EOR. SSS involvement increased recurrence risk (OR, 12.69; 95% CI, 1.46-110.27; P = 0.021), whereas GTR tended to decrease it (OR, 0.26; 95% CI, 0.06-1.09; P = 0.065).

CONCLUSIONS

Adjuvant RT does not seem to be a pivotal criterion to reduce the recurrence rate in patients with grade I meningioma, even when venous sinuses are involved.

Early outcomes of conformal radiotherapy in the treatment of cavernous sinus meningioma

Aim: Cavernous sinus tumours represent 1% of all intracranial neoplasms, and 41% of them are cavernous sinus meningiomas (CSM). The disappointing results of the microsurgical approach in the treatment of CSM have led to the evaluation of a more conservative strategy, such as conformal radiotherapy (CR) and stereotactic radiosurgery (SRS). Here we report our experience with CR in the treatment of CSM, aiming to evaluate local control, clinical response and radiation-induced toxicity. Methods: A total of 18 patients with CSM, treated from 2011 to 2017, were retrospectively reviewed. Results: Patient median age was 59 years [31–74]. Clinical presentation included impaired vision, cranial nerve deficit, headache, ocular signs. Median tumour size was 35 mm [13–56]. Six patients were operated before the radiation. Twelve patients were treated with definitive radiotherapy. Dose of radiation varied from 50.4 Gy in 28 fractions, to 54 Gy in 30 fractions. Median follow-up was 33 months [6–84]. Among the 18 patients, patient’s signs and symptoms of disease remained unchanged in three cases (16.66%), 12 (66.66%) were improved and 1 patient (5.55%) exhibited tumour progression (exophthalmia). Two patients (11.11%) were lost to follow-up after the end of the treatment with radiotherapy. Findings: Based on our study findings, CR has proved to be a relatively safe and effective therapeutic option in the treatment of CSM, whether used as first-line or as an adjuvant treatment. CR may be particularly effective for tumours that are not amenable to SRS, owing to lesion size (> 30-35 mm) and/or proximity to the optic apparatus (<3 mm).

Cognitive Decline Secondary to Therapeutic Brain Radiation-Similarities and Differences to Traumatic Brain Injury

Traumatic brain injury (TBI) resulting from forceful impacts on the torso and head has been of major interest because of the prevalence of such injuries in military personnel, contact sports and the elderly. Cognitive and behavioral changes associated with TBI are also seen following whole brain radiation treatment for cancer and chemotherapy for disseminated tumors. The biological mechanisms involved in the initiation of TBI from impact, radiation, and chemotherapy to loss of cognitive function have several shared characteristics including increases in blood brain barrier permeability, blood vessel density, increases in inflammatory and autoimmune responses, alterations in NMDA and glutamate receptor levels and release of proteins normally sequestered in the brain into the blood and spinal fluid. The development of therapeutic agents that mitigate the loss of cognition and development of behavioral disorders in patients experiencing radiation-induced injury may provide benefit to those with TBI when similar processes are involved on a cellular or molecular level. Increased collaborative efforts between the radiation oncology and the neurology and psychiatry communities may be of major benefit for the management of brain injury from varied environmental insults.

Hypofractionated Stereotactic Radiotherapy for Patients with Intracranial Meningiomas: impact of radiotherapy regimen on local control

We evaluated efficacy and tolerance of hypofractionated stereotactic radiation treatment (hFSRT) in the management of intracranial meningiomas. Between December 2008 and June 2016, 126 patients with 136 intracranial meningiomas were treated with robotic hFSRT. hFSRT was performed as primary irradiation and as a salvage option for the local recurrence after prior radiotherapy. The median prescription dose was 25 Gy (12–40) with a median number of fractions of 5 (3–10). After a median follow-up of 20.3 months (range 1–77 months), the 24-months local control (LC) rate was 81% in the primary hFSRT group and 39% after hFSRT in the re-irradiation group (p=0.002). The clinical control rate of symptoms in the overall population was 95% (95% CI: 89–98%). Progression-free survival (PFS) in the overall population at 24 months was 70% (95% CI: 60%–79%). In the primary hFSRT group, PFS was significantly lower with the most hypofractionated schedules of 21–23 Gy in 3 fractions vs. 25–40 Gy in 5–10 fractions: 62% vs. 92% (p = 0.0006). The incidence of radionecrosis at 24 months was significantly lower in the primary hFSRT group, at 2% vs. 20% in the re-irradiation hFSRT group (p = 0.002).

Histopathological features predictive of local control of atypical meningioma after surgery and adjuvant radiotherapy

OBEJECTIVE

The goal of this study was to investigate the impact of adjuvant radiotherapy (RT) on local recurrence and overall survival in patients undergoing primary resection of atypical meningioma, and to identify predictive factors to inform patient selection for adjuvant RT.

METHODS

One hundred eighty-two patients who underwent primary resection of atypical meningioma at a single institution between 1993 and 2014 were retrospectively identified. Patient, meningioma, and treatment data were extracted from the medical record and compared using the Kaplan-Meier method, log-rank tests, multivariate analysis (MVA) Cox proportional hazards models with relative risk (RR), and recursive partitioning analysis.

RESULTS

The median patient age and imaging follow-up were 57 years (interquartile range [IQR] 45–67 years) and 4.4 years (IQR 1.8–7.5 years), respectively. Gross-total resection (GTR) was achieved in 114 cases (63%), and 42 patients (23%) received adjuvant RT. On MVA, prognostic factors for death from any cause included GTR (RR 0.4, 95% CI 0.1–0.9, p = 0.02) and MIB1 labeling index (LI) ≤ 7% (RR 0.4, 95% CI 0.1–0.9, p = 0.04). Prognostic factors on MVA for local progression included GTR (RR 0.2, 95% CI 0.1–0.5, p = 0.002), adjuvant RT (RR 0.2, 95% CI 0.1–0.4, p < 0.001), MIB1 LI ≤ 7% (RR 0.2, 95% CI 0.1–0.5, p < 0.001), and a remote history of prior cranial RT (RR 5.7, 95% CI 1.3–18.8, p = 0.03). After GTR, adjuvant RT (0 of 10 meningiomas recurred, p = 0.01) and MIB1 LI ≤ 7% (RR 0.1, 95% CI 0.003–0.3, p < 0.001) were predictive for local progression on MVA. After GTR, 2.2% of meningiomas with MIB1 LI ≤ 7% recurred (1 of 45), compared with 38% with MIB1 LI > 7% (13 of 34; p < 0.001). Recursive partitioning analysis confirmed the existence of a cohort of patients at high risk of local progression after GTR without adjuvant RT, with MIB1 LI > 7%, and evidence of brain or bone invasion. After subtotal resection, adjuvant RT (RR 0.2, 95% CI 0.04–0.7, p = 0.009) and ≤ 5 mitoses per 10 hpf (RR 0.1, 95% CI 0.03–0.4, p = 0.002) were predictive on MVA for local progression.

CONCLUSIONS

Adjuvant RT improves local control of atypical meningioma irrespective of extent of resection. Although independent validation is required, the authors’ results suggest that MIB1 LI, the number of mitoses per 10 hpf, and brain or bone invasion may be useful guides to the selection of patients who are most likely to benefit from adjuvant RT after resection of atypical meningioma.

Review of photon and proton radiotherapy for skull base tumours

An extremely large variety of benign and malignant tumours occur at skull base; these tumour lesions are in the proximity to structures deputed to relevant physiologic functions, limiting extensive surgical approaches to this body district. Most recent progresses of surgery and radiotherapy have allowed to improve local control with acceptable rates of side effects. Various photon radiotherapy techniques are employed, including 3-dimensional conformal radiotherapy, intensity modulated radiotherapy (IMRT), stereotactic radiotherapy (SRT) and brachytherapy that is manly limited to the treatment of primary or recurrent nasopharyngeal carcinoma. Proton beam radiotherapy is also extensively used thanks to its physical characteristics. Our review, focusing in particular on meningioma, chordoma, and chondrosarcoma, suggests that proton therapy plays a major role in the treatment of malignant tumours whereas photon therapy still plays a relevant role in the treatment of benign tumour lesions.

Atypical and anaplastic meningiomas in a public hospital in São Paulo State, Brazil

Atypical/anaplastic (World Health Organization (WHO) grades II and III) are less common and have poorer outcomes than benign meningiomas. This study aimed to analyze the outcome of patients with these tumors.Method Overall/recurrence-free survivals (RFS) and the Karnofsky Performance Scale of 52 patients with grades II (42) and III (9) meningiomas surgically treated were analyzed (uni/multivariate analysis).Results Total/subtotal resections were 60.8%/35.3%. Patients <60 years-old and grade II tumors had longer survival. Grade II tumors, total resection andde novo meningioma had better RFS (univariate analysis). Patients >60 years-old, de novo meningioma and radiotherapy had longer survival and patients <60 years-old and with grade II tumors had longer RFS (multivariate analysis). Recurrence rate was 51% (39.2% Grade II and 66.7% Grade III). Operative mortality was 1.9%.Conclusion Age <60 years-old, grade II tumors and de novomeningiomas were the main predictors for better prognosis among patients with grades II and III meningiomas.

Hypofractionated stereotactic radiotherapy for benign intracranial tumours of the cavernous sinus

We present our experience with hypofractionated stereotactic radiotherapy (HSRT) using 15 fractions to treat benign conditions of the cavernous sinus (CS) and emphasise the outcome in terms of cranial nerve (CN) function and toxicity for long term safety and efficacy. We performed a retrospective review of prospectively collected data on 112 patients with benign tumours of the CS treated with HSRT between 1 January 1998 and 31 December 2009. While all tumours involved the CS, a separate analysis was undertaken for meningiomas and pituitary adenomas. The median follow-up was 77 months (range: 2.3-177). Fifty-seven patients (51%) had a diagnosis of meningioma and 55 (49%) had pituitary adenomas. Prior to HSRT, 82 patients (73%) underwent microsurgery. The median tumour volume was 6.6 cm(3) for meningiomas and 3.4 cm(3) for pituitary adenomas (interquartile range: 2.8-7.9), and the mean prescribed dose was 38 Gy (range: 37.5-40.0) to the tumour margin, delivered in 15 fractions. After HSRT, 57% of all preexisting cranial neuropathies either resolved or improved and 38% remained stable, whereas 5% deteriorated. The diagnosis of meningioma was the only variable associated with recovery of cranial neuropathy (p<0.001). Permanent CN complications occurred in three patients (3%). The 5 and 10 year actuarial freedom from progression for patients with meningiomas was 98% and 93%, respectively, and for patients with pituitary adenomas this was 96% and 96%, respectively. We demonstrate low rates of CN morbidity after HSRT and the possibility of resolution or improvement in CN function for common histologies involving the CS.

Meningiomas: knowledge base, treatment outcomes, and uncertainties. A RANO review

Evolving interest in meningioma, the most common primary brain tumor, has refined contemporary management of these tumors. Problematic, however, is the paucity of prospective clinical trials that provide an evidence-based algorithm for managing meningioma. This review summarizes the published literature regarding the treatment of newly diagnosed and recurrent meningioma, with an emphasis on outcomes stratified by WHO tumor grade. Specifically, this review focuses on patient outcomes following treatment (either adjuvant or at recurrence) with surgery or radiation therapy inclusive of radiosurgery and fractionated radiation therapy. Phase II trials for patients with meningioma have recently completed accrual within the Radiation Therapy Oncology Group and the European Organisation for Research and Treatment of Cancer consortia, and Phase III studies are being developed. However, at present, there are no completed prospective, randomized trials assessing the role of either surgery or radiation therapy. Successful completion of future studies will require a multidisciplinary effort, dissemination of the current knowledge base, improved implementation of WHO grading criteria, standardization of response criteria and other outcome end points, and concerted efforts to address weaknesses in present treatment paradigms, particularly for patients with progressive or recurrent low-grade meningioma or with high-grade meningioma. In parallel efforts, Response Assessment in Neuro-Oncology (RANO) subcommittees are developing a paper on systemic therapies for meningioma and a separate article proposing standardized end point and response criteria for meningioma.

Long-term survival analysis of atypical meningiomas: survival rates, prognostic factors, operative and radiotherapy treatment

BACKGROUND

The rarity and the inconsistent criteria for defining atypical meningioma prior to the WHO 2007 classification made its management and prognostic factors poorly understood. Only few articles have addressed the survival rates of WHO-classified atypical meningiomas. The small number or the disproportionate representation of irradiated patients was a weakness for these articles. This study evaluated whether the extent of surgery and receiving adjuvant radiotherapy after an initial operation along with other patient characteristics influenced the recurrence and survival rates of atypical meningiomas.

METHODS

The clinical and surgical notes of the 79 patients with grade II atypical meningioma treated at our center over 13 years were retrospectively evaluated. The histology grading was consistent with WHO 2007 classification. The Simpson grading system was used to assess the extent of surgical resection. Kaplan Meier analysis, Cox multivariate regression analysis, and the Log-rank test were conducted using STATA® statistical package.

RESULTS

The average age at the time of initial operation was 58 years, and 54 % were males. The mean follow-up period was 50 months. In Cox multivariate analysis, only Simpson grading was predictive of recurrence (hazard ratio = 2.22 / 1 increase in Simpson grade. p = 0.003). Simpson grade I patients had a relapse-free survival rate of 97 and 74 % at one and five years, respectively, compared with 88 and 32 % in the subtotal resection group (Simpson grades II to IV). There was no statistically significant correlation between recurrence and subjecting patients to postoperative radiotherapy. Apart from Simpson grade I patients, there was a general trend for worse outcome in irradiated patients.

CONCLUSIONS

The most important prognostic factor in determining recurrence was Simpson grading. There was no statistically significant impact of adjuvant radiotherapy on the recurrence of atypical meningiomas. Meta-analysis for the existing literature is needed.

Outcomes and patterns of failure for grade 2 meningioma treated with reduced-margin intensity modulated radiation therapy

PURPOSE

The purpose of this study was to evaluate intracranial control and patterns of local recurrence (LR) for grade 2 meningiomas treated with intensity modulated radiation therapy (IMRT) with limited total margin expansions of ≤1 cm.

METHODS AND MATERIALS

We reviewed records of patients with a neuropathological diagnosis of grade 2 meningioma who underwent IMRT at our institution between 2002 and 2012. Actuarial rates were determined by the Kaplan-Meier method from the end of RT. LR was defined as in-field if ≥90% of the recurrence was within the prescription isodose, out-of-field (marginal) if ≥90% was outside of the prescription isodose, and both if neither criterion was met.

RESULTS

Between 2002 and 2012, a total of 54 consecutive patients underwent IMRT for grade 2 meningioma. Eight of these patients had total initial margins >1 cm and were excluded, leaving 46 patients for analysis. The median imaging follow-up period was 26.2 months (range, 7-107 months). The median dose for fractionated IMRT was 59.4 Gy (range, 49.2-61.2 Gy). Median clinical target volume (CTV), planning target volume (PTV), and total margin expansion were 0.5 cm, 0.3 cm, and 0.8 cm, respectively. LR occurred in 8 patients (17%), with 2-year and 3-year actuarial local control (LC) of 92% and 74%, respectively. Six of 8 patients (85%) had a known pattern of failure. Five patients (83%) had in-field LR; no patients had marginal LR; and 1 patient (17%) had both.

CONCLUSIONS

The use of IMRT to treat grade 2 meningiomas with total initial margins (CTV + PTV) ≤1 cm did not appear to compromise outcomes or increase marginal failures compared with other modern retrospective series. Of the 46 patients who had margins ≤1 cm, none experienced marginal failure only. These results demonstrate efficacy and low risk of marginal failure after IMRT treatment of grade 2 meningiomas with reduced margins, warranting study within a prospective clinical trial.

Role of external beam radiotherapy in the treatment of relapsing meningioma

The role of radiotherapy in the treatment of relapsing meningiomas is not well established. Data of patients treated with radiotherapy for a relapsing meningioma were retrospectively analyzed. Overall survival (OS) was the primary endpoint of the analysis. Local control and acute and late toxicity rates have been also reported. From April 1986 to February 2011, 37 patients with a diagnosis of recurrent meningioma were treated. Median age was 64 years (range 36-79). A total of 18, 10, 5 and 4 patients were affected by relapsing benign, atypical, malignant meningiomas and meningiosarcomas, respectively (WHO classification). Median dose was 60 Gy (range 46-66 Gy). The median follow-up was 42 months (range 3-300 months). OS at 1, 3, 5 and 8 years was 81, 55.6, 43.9 and 25.8%, respectively (median OS 45 months). A strong statistical trend was observed toward better OS rates in patients treated with radiotherapy at first recurrence compared to those treated at the second (or more) recurrence (OS 50.5 vs. 30.8%, p=0.055). A statistical impact of the histology (WHO I vs. II, III and IV) on 5-year OS was also observed (OS 60 vs. 30%, 0 and 0%, p=0.010). Radiotherapy has been well tolerated, with no G2-4 neurological toxicity (RTOG toxicity score). Conventional radiation therapy has an important role in multidisciplinary approach in the treatment of recurrence of meningiomas. The histological type and the timing of the radiotherapy are prognostic factors in terms of survival.

A Phase I Study of Tomotherapy in Patients With Primary Benign and Low-grade Brain Tumors: Late Toxicity and Quality of Life

OBJECTIVES

To evaluate longitudinal quality of life and late neurotoxicity (>12 mo) of tomotherapy in patients with primary benign and low-grade brain tumors.

METHODS

Between January 2006 and October 2009, 49 patients with brain tumors were treated with tomotherapy at 2 radiotherapy centers in Canada. The median age of the patients was 51.0 years (range, 21 to 74 y); there were 21 men (42.86%) and 28 women (57.14%). All 49 patients had an initial Karnofsky performance score ≥70. One patient (2.04%) received 45 Gy in 25 fractions, 27 patients (55.10%) received 50.4 Gy in 28 fractions, 15 patients (30.6%) received 54 Gy in 30 fractions, and 5 patients (10.2%) received 60 Gy in 30 fractions. A total of 47 patients were analyzed for late toxicity and outcomes.

RESULTS

Changes in the Karnofsky Performance Status of the patients did not reach statistical significance (P>0.05). The majority of the quality of life parameters that reached a statistically significant level (P<0.05) of change at 2 years were changes toward improvement (drowsiness, itchy skin, emotional functioning, fatigue, nausea, and appetite). Statistically significant (P<0.05) interval deterioration in physical, role, and social functioning was observed. Actuarial overall survival at 5 years was 91.6%; disease-free survival at 5 years was 86.6%.

CONCLUSIONS

IMRT helical tomotherapy is well tolerated, without statistically significant constitutional and late neurotoxicity up to the 2-year mark.

Controversies in radiotherapy for meningioma

Meningiomas are the most common primary intracranial tumour. Although external beam radiotherapy and radiosurgery are well-established treatments, affording local control rates of 85-95% at 10 years, the evidence base is mainly limited to single institution case series. This has resulted in inconsistent practices. It is generally agreed that radiotherapy is an established primary therapy in patients requiring treatment for surgically inaccessible disease and postoperatively for grade 3 tumours. Controversy exists surrounding whether radiotherapy should be upfront or reserved for progression for incompletely excised and grade 2 tumours. External beam radiotherapy and radiosurgery have not been directly compared, but seem to offer comparable rates of control for benign disease. Target volume definition remains contentious, including the inclusion of hyperostotic bone, dural tail and surrounding brain, but pathological studies are shedding some light. Most agree that doses around 50-54 Gy are appropriate for benign meningiomas and ongoing European Organization for Research and Treatment of Cancer and Radiation Therapy Oncology Group studies are evaluating dose escalation for higher risk disease. Here we address the 'who, when and how' of radiotherapy for meningioma.

Benign orbital apex tumors treated with multisession gamma knife radiosurgery

OBJECTIVE

The orbital apex is an important anatomic landmark that hosts numerous critical neurovascular structures. Tumor resection performed at this complex region poses a therapeutic challenge to orbital surgeons and often is associated with significant visual morbidity. This article reports the efficacy and safety of multisession gamma knife radiosurgery (GKRS) in benign, well-circumscribed tumors located at the orbital apex.

DESIGN

Retrospective interventional case series.

PARTICIPANTS

Five patients with visual disturbances resulting from a benign, well-circumscribed orbital apex tumor (3 cases of cavernous hemangioma and 2 cases of schwannoma).

METHODS

Each patient treated with GKRS with a total radiation dose of 20 Gy in 4 sessions (5 Gy in each session with an isodose line of 50%) delivered to the tumor margin.

MAIN OUTCOME MEASURES

Best-corrected visual acuity, visual field changes, orbital imaging, tumor growth control, and side effects of radiation.

RESULTS

All patients demonstrated improvement in visual acuity, pupillary responses, color vision, and visual field. Tumor shrinkage was observed in all patients and remained stable until the last follow-up. No adverse events were noted during or after the radiosurgery. None of the patients experienced any radiation-related ocular morbidity.

CONCLUSIONS

From this experience, multisession GKRS seems to be an effective management strategy to treat solitary, benign, well-circumscribed orbital apex tumors.

Impaired survival and long-term neurological problems in benign meningioma

PURPOSE

To assess long-term functional outcome and survival among patients with meningioma World Health Organization (WHO) grade I.

METHODS

Retrospective analysis of 205 patients after resection of WHO grade I intracranial meningioma from 1985 through 2003. Expected age- and sex-specific survival was calculated by applying Dutch life-table statistics to each patient for the individual duration of follow-up. Long-term functional outcome was assessed using a mailed questionnaire to the general practitioner.

RESULTS

The mean duration of follow-up was 11.5 years. Survival at 5, 10, 15, and 20 years was 92%, 81%, 63%, and 53%, respectively, which is significantly lower than the expected survival (94%, 86%, 78%, and 66%, respectively). Survival was worse with higher age (P < .001). Survival among patients younger than 45 years and older than 65 years was comparable to the expected survival but significantly worse among patients aged 45-65 years. Analysis of the cause of death suggests an excess mortality associated with both brain tumor death and stroke (P = .07). Recurrence rates at 5, 10, and 15 years were 18%, 26%, and 32%, respectively. Higher Simpson grade (P < .001) and lower age (P = .02) were associated with a higher recurrence rate. In 29 patients (14%) receiving radiotherapy, the 5-year recurrence rate was 18% and the 5-year survival was only 58%. Long-term functioning (≥ 5 years after last treatment) could be assessed in 89 long-term survivors: 29 patients (33%) showed no deficits, and 60 (67%) showed at least 1 neurological symptom, of whom 24 (27%) were unable to perform normal daily activities.

CONCLUSION

Long-term survival in WHO grade I meningioma is challenged in patients more than 45 years of age. Excess mortality seems to be associated with both tumor recurrence and stroke. The majority of patients have long-term neurological problems.

Fractionated stereotactic conformal radiotherapy for large benign skull base meningiomas

Purpose

to assess the safety and efficacy of fractionated stereotactic radiotherapy (FSRT) for large skull base meningiomas.

Methods and Materials

Fifty-two patients with large skull base meningiomas aged 34-74 years (median age 56 years) were treated with FSRT between June 2004 and August 2009. All patients received FSRT for residual or progressive meningiomas more than 4 centimeters in greatest dimension. The median GTV was 35.4 cm³ (range 24.1-94.9 cm³), and the median PTV was 47.6 cm³ (range 33.5-142.7 cm³). Treatment volumes were achieved with 5-8 noncoplanar beams shaped using a micromultileaf collimator (MLC). Treatment was delivered in 30 daily fractions over 6 weeks to a total dose of 50 Gy using 6 MV photons. Outcome was assessed prospectively.

Results

At a median follow-up of 42 months (range 9-72 months) the 3-year and 5-year progression-free survival (PFS) rates were 96% and 93%, respectively, and survival was 100%. Three patients required further debulking surgery for progressive disease. Hypopituitarism was the most commonly reported late complication, with a new hormone pituitary deficit occurring in 10 (19%) of patients. Clinically significant late neurological toxicity was observed in 3 (5.5%) patients consisting of worsening of pre-existing cranial deficits.

Conclusion

FSRT as a high-precision technique of localized RT is suitable for the treatment of large skull base meningiomas. The local control is comparable to that reported following conventional external beam RT. Longer follow-up is required to assess long term efficacy and toxicity, particularly in terms of potential reduction of treatment-related late toxicity.

Visual outcome in meningiomas around anterior visual pathways treated with linear accelerator fractionated stereotactic radiotherapy

PURPOSE

Meningiomas threatening the anterior visual pathways (AVPs) and not amenable for surgery are currently treated with multisession stereotactic radiotherapy. Stereotactic radiotherapy is available with a number of devices. The most ubiquitous include the gamma knife, CyberKnife, tomotherapy, and isocentric linear accelerator systems. The purpose of our study was to describe a case series of AVP meningiomas treated with linear accelerator fractionated stereotactic radiotherapy (FSRT) using the multiple, noncoplanar, dynamic conformal rotation paradigm and to compare the success and complication rates with those reported for other techniques.

PATIENTS AND METHODS

We included all patients with AVP meningiomas followed up at our neuro-ophthalmology unit for a minimum of 12 months after FSRT. We compared the details of the neuro-ophthalmologic examinations and tumor size before and after FSRT and at the end of follow-up.

RESULTS

Of 87 patients with AVP meningiomas, 17 had been referred for FSRT. Of the 17 patients, 16 completed >12 months of follow-up (mean 39). Of the 16 patients, 11 had undergone surgery before FSRT and 5 had undergone FSRT as first-line management. Tumor control was achieved in 14 of the 16 patients, with three meningiomas shrinking in size after RT. Two meningiomas progressed, one in an area that was outside the radiation field. The visual function had improved in 6 or stabilized in 8 of the 16 patients (88%) and worsened in 2 (12%).

CONCLUSIONS

Linear accelerator fractionated RT using the multiple noncoplanar dynamic rotation conformal paradigm can be offered to patients with meningiomas that threaten the anterior visual pathways as an adjunct to surgery or as first-line treatment, with results comparable to those reported for other stereotactic RT techniques.

Radiotherapy and radiosurgery for benign skull base meningiomas

Meningiomas located in the region of the base of skull are difficult to access. Complex combined surgical approaches are more likely to achieve complete tumor removal, but frequently at a cost of treatment related high morbidity. Local control following subtotal excision of benign meningiomas can be improved with conventional fractionated external beam radiation therapy with a reported 5-year progression-free survival up to 95%. New radiation techniques, including stereotactic radiosurgery (SRS), fractionated stereotactic radiotherapy (FSRT), and intensity-modulated radiotherapy (IMRT) have been developed as a more accurate technique of irradiation with more precise tumor localization, and consequently a reduction in the volume of normal brain irradiated to high radiation doses. SRS achieves a high tumour control rate in the range of 85-97% at 5 years, although it should be recommended only for tumors less than 3 cm away more than 3 mm from the optic pathway because of high risk of long-term neurological deficits. Fractionated RT delivered as FSRT, IMRT and protons is useful for larger and irregularly or complex-shaped skull base meningiomas close to critical structures not suitable for single-fraction SRS. The reported results indicate a high tumour control rate in the range of 85-100% at 5 years with a low risk of significant incidence of long-term toxicity. Because of the long natural history of benign meningiomas, larger series and longer follow-up are necessary to compare results and toxicity of different techniques.

Gamma Knife surgery of large meningiomas: early response to treatment

PURPOSE

Gamma Knife treatment is traditionally limited to tumours with a diameter not exceeding 3-3.5 cm. The current paper presents 97 patients with meningiomas with a minimum volume of 10 cm(3), treated with a prescription dose of 12 Gy (or sometimes less to protect neighbouring structures). The post-treatment assessment of these patients, the early response to treatment and the complications of treatment are presented.

METHODS

There were 97 patients, 70 females and 27 males. The mean age was 48.1 years (range 20.4-87.2 years). The mean follow-up was 54 months (range 25-86 months). All tumours had a volume of 10 cm(3) or more. The mean volume was 15.9 cm(3) (range 10.0-43.2 cm(3)). Post-treatment follow-up used quantitative and qualitative assessments, which are described.

RESULTS

No tumour continued to grow. Twenty-seven were smaller and 72 unchanged in volume. Three patients suffered adverse radiation effects (defined as a new post-treatment oedema detected on the magnetic resonance image with or without contrast leakage). In one case this was silent. In two cases the clinical and radiological effects were temporary and resolved completely.

CONCLUSIONS

It is suggested on the basis of this material that the dosimetry used here permits the safe Gamma Knife treatment of larger meningiomas within the range reported. The early radiological response is encouraging, but further follow-up is needed to check long term tumour control. A qualitative method of tumour volume assessment is presented. It seems to be a simpler and more reliable way of assessing tumour volume changes than other methods currently in routine use.

Radiotherapy as an adjuvant in the management of intracranial meningiomas: are we practising evidence-based medicine?

Although increasingly used, the precise role of radiotherapy in the management of meningiomas is still disputed. The objective of this study, therefore, was to appraise the evidence for adjuvant radiotherapy in benign and atypical intracranial meningiomas, and to compare and contrast it with the current opinion and practice of neurosurgeons in the United Kingdom and the Republic of Ireland. The use of radiotherapy as a primary treatment strategy or its use in the treatment of recurrence was not considered. We performed a systematic review of the evidence for adjuvant radiotherapy in benign and atypical intracranial meningiomas, surveyed current opinion amongst neurosurgeons involved in such cases and ascertained local practice using data from the regional cancer registry. Overall, 10 cohorts were identified that fulfilled our eligibility criteria. Four studies showed significantly improved local control in patients receiving adjuvant radiotherapy for incompletely resected grade I meningiomas. Our survey demonstrated that the vast majority (98%) of neurosurgeons would not recommend adjuvant radiotherapy in grade I meningioma. In grade II meningioma, most (80%) would not advocate adjuvant radiotherapy if completely excised, but the majority (59%) would recommend radiotherapy in cases of subtotal resection. Significant variation in opinion between centres exists, however, particularly in cases of completely resected atypical meningiomas (p = 0.02). Data from the Eastern Cancer Registration and Information Centre appears to be in line with these findings: less than 10% of patients with grade I meningiomas, but almost 30% of patients with grade II meningiomas received adjuvant radiotherapy in the Eastern region. In conclusion, our study has highlighted significant variation in opinion and practice, reflecting a lack of class 1 evidence to support the use of adjuvant radiotherapy in the treatment of meningiomas. Efforts are underway to address this with a randomized multicentre trial comparing a policy of watchful waiting versus adjuvant irradiation.

Atypical and malignant meningioma: outcome and prognostic factors in 119 irradiated patients. A multicenter, retrospective study of the Rare Cancer Network

PURPOSE

To retrospectively analyze and assess the outcomes and prognostic factors in a large number of patients with atypical and malignant meningiomas.

METHODS AND MATERIALS

Ten academic medical centers participating in this Rare Cancer Network contributed 119 cases of patients with atypical or malignant meningiomas treated with external beam radiotherapy (EBRT) after surgery or for recurrence. Eligibility criteria were histologically proven atypical or anaplastic (malignant) meningioma (World Health Organization Grade 2 and 3) treated with fractionated EBRT after initial resection or for recurrence, and age >18 years. Sex ratio (male/female) was 1.3, and mean (+/-SD) age was 57.6 +/- 12 years. Surgery was macroscopically complete (Simpson Grades 1-3) in 71% of patients; histology was atypical and malignant in 69% and 31%, respectively. Mean dose of EBRT was 54.6 +/- 5.1 Gy (range, 40-66 Gy). Median follow-up was 4.1 years.

RESULTS

The 5- and 10-year actuarial overall survival rates were 65% and 51%, respectively, and were significantly influenced by age >60 years (p = 0.005), Karnofsky performance status (KPS) (p = 0.01), and high mitotic rate (p = 0.047) on univariate analysis. On multivariate analysis age >60 years (p = 0.001) and high mitotic rate (p = 0.02) remained significant adverse prognostic factors. The 5- and 10-year disease-free survival rates were 58% and 48%, respectively, and were significantly influenced by KPS (p = 0.04) and high mitotic rate (p = 0.003) on univariate analysis. On multivariate analysis only high mitotic rate (p = 0.003) remained a significant prognostic factor.

CONCLUSIONS

In this multicenter retrospective study, age, KPS, and mitotic rate influenced outcome. Multicenter prospective studies are necessary to clarify the management and prognostic factors of such a rare disease.

Role of radiation therapy in treating intracranial meningiomas

Surgery is the mainstay for many patients with meningiomas, and it remains the standard. In large single-institution series, gross-total resection has been reported to achieve 5-, 10-, and 15-year recurrence-free survival rates of approximately 90, 80, and 70%, respectively. There are a growing number of series of patients with prolonged follow-up in which authors have evaluated fractionated external-beam radiation therapy (EBRT) either as an adjuvant to surgery for subtotally resected, recurrent, or higher-grade meningiomas, or as an alternative to surgery. The primary focus of this review is EBRT, but to lend perspective, a comparative analysis of surgery and radiosurgery is also provided.

Gamma Knife surgery for benign meningioma

Object

Meningioma is the most frequent benign tumor treated with Gamma Knife surgery (GKS); however, the assessment of its efficacy and safety in slow-growing tumors is an ongoing process, requiring analysis of long-term results.

Methods

Three hundred sixty-eight patients harboring 400 meningiomas treated between 1992 and 1999 at Na Homolce Hospital were evaluated. The median patient age was 57 years (range 18–84 years). The median tumor volume was 4.4 cm3 (range 0.11–44.9 cm3). The median tumor margin dose to the 50% isodose line was 12.55 Gy (range 6.5–24 Gy). Descriptive analysis was performed in 331 patients (90%); 325 patients had a follow-up longer than 24 months (median 60 months), and six patients were included because of posttreatment complications. The volume of treated tumors decreased in 248 cases (69.7%), remained the same in 99 (27.8%), and increased in nine (2.5%). The actuarial tumor control rate was 97.9% at 5 years post-GKS. Perilesional edema after radiosurgery was confirmed on neuroim-aging in 51 patients (15.4%). The temporary and permanent morbidity rates after radiosurgery were 10.2 and 5.7%, respectively.

Results

A significantly higher incidence of tumor volume increase was observed in men compared with women and in tumors treated with a margin dose lower than 12 Gy. Significant risk factors for edema included an age greater than 60 years, no previous surgery, perilesional edema before radiosurgery, a tumor volume greater than 10 cm3, a tumor location in the anterior fossa, and a margin dose greater than 16 Gy.

Conclusions

Stereotactic radiosurgery is a safe method of treatment for meningiomas. A minimum margin dose of 12 to 16 Gy seems to represent the therapeutic window for benign meningiomas with a high tumor control rate in a mid-term follow-up period.

Visual field preservation after multisession cyberknife radiosurgery for perioptic lesions

OBJECTIVE

The restricted radiation tolerance of the anterior visual pathways represents a unique challenge for ablating adjacent lesions with single-session radiosurgery. Although preliminary studies have recently demonstrated that multisession radiosurgery for selected perioptic tumors is both safe and effective, the number of patients in these clinical series was modest and the length of follow-up limited. The current retrospective study is intended to help address these shortcomings.

METHODS

Forty-nine consecutive patients with meningioma (n = 27), pituitary adenoma (n = 19), craniopharyngioma (n = 2), or mixed germ cell tumor (n = 1) situated within 2 mm of a "short segment" of the optic apparatus underwent multisession image-guided radiosurgery at Stanford University Medical Center. Thirty-nine of these patients had previous subtotal surgical resection, and six had previously been treated with conventional fractionated radiotherapy (6). CyberKnife radiosurgery was delivered in two to five sessions to an average tumor volume of 7.7 cm3 and a cumulative average marginal dose of 20.3 Gy. Formal visual testing and clinical examinations were performed before treatment and at follow-up intervals beginning at 6 months.

RESULTS

After a mean visual field follow-up of 49 months (range, 6-96 mo), vision was unchanged postradiosurgery in 38 patients, improved in eight (16%), and worse in three (6%). In each instance, visual deterioration was accompanied by tumor progression that ultimately resulted in patient death. However, one of these patients, who had a multiply recurrent adrenocorticotropic hormone-secreting pituitary adenoma, initially experienced early visual loss without significant tumor progression after both a previous course of radiotherapy and three separate sessions of radiosurgery. After a mean magnetic resonance imaging follow-up period of 46 months, tumor volume was stable or smaller in all other cases. Two patients died of unrelated nonbrain causes.

CONCLUSION

Multisession radiosurgery resulted in high rates of tumor control and preservation of visual function in this group of perioptic tumors. Ninety-four percent of patients retained or improved preradiosurgical vision. This intermediate-term experience reinforces the findings from earlier studies that suggested that multisession radiosurgery can be a safe and effective alternative to either surgery or fractionated radiotherapy for selected lesions immediately adjacent to short segments of the optic apparatus.

Diagnosis and treatment of atypical and anaplastic meningiomas: a review

Atypical and anaplastic meningiomas are uncommon tumors with a poorer prognosis than benign meningiomas. We reviewed the current literature and attempted to integrate and summarize available information to determine a logical approach to these tumors. Both tumors are rare and are often integrated with benign meningiomas when treatments are evaluated. In addition, because there has not been one histopathological classification scheme for atypical and anaplastic meningiomas in the past, there are numerous inconsistencies in the literature. Malignant progression with accumulation of mutations in a benign meningioma can result in an atypical and/or anaplastic meningioma. Both tumors are difficult to manage and have high recurrence and poor survival rates. The extent of tumor resection and histological grade are the key determinants for recurrence. In addition, metastases are unusual, but they do occur. We also review the evidence available that has resulted in the current World Health Organization classification. Radiation therapy can be used as an adjunctive treatment after both total and subtotal resection. In addition, the role of stereotactic radiosurgery is increasing, along with a possible role for brachytherapy. There are no effective chemotherapeutic agents available. A treatment algorithm is suggested.

Fractionated stereotactic radiotherapy in the treatment of exclusive cavernous sinus meningioma: functional outcome, local control, and tolerance

BACKGROUND

Fractionated stereotactic radiotherapy (FSRT) combines the precision of stereotactic positioning with the radiobiologic advantage of dose fractionation.

METHODS

From June 1997 to June 2001, 30 patients with cavernous sinus meningiomas were treated with FSRT using fixed noncoplanar conformal fields. Patient skull fixation was achieved using the BrainLAB mask (20 patients) or Beverly frame (10 patients). The Cosman-Roberts-Wells coordinate frame was used for stereotactic space definition. In selected cases before 1999, and in all cases afterward, gadolinium-enhanced MRI for image fusion was performed. The median radiation dose was 52 Gy, with a daily fraction of 2 Gy. Patients were regularly followed up analyzing symptoms, tumor progression, and side effects. Neurocognitive function was evaluated retrospectively for 26 patients using Mini-Mental State Examination.

RESULTS

Median follow-up period was 50 months (range, 28.2-74.5 months). Preexisting neurologic symptoms improved in 50% of the patients and worsened in 2 patients. Only 2 patients progressed and the actuarial local progression free survival was 93% at 4 years. Tolerance was good with 2 cases of late radiation toxicity which consisted of moderate short-term memory loss and dysphasia in one case and neuropsychologic deficit with seizures in the other. Postradiotherapy Mini-Mental State Examination results showed a median score of 28 (range, 16-30).

CONCLUSIONS

Fractionated stereotactic radiotherapy is a high-precision technique. It is safe and feasible in the primary and adjuvant treatment of cavernous sinus meningiomas. Fractionated stereotactic radiotherapy allowed local control in more than 90% of patients.

Prolonged Oral Hydroxyurea and Concurrent 3d-Conformal Radiation in Patients with Progressive or Recurrent Meningioma: Results of a Pilot Study

PURPOSE

Treatment of recurrent and progressive meningiomas remains a challenge in clinical neurooncology. This study was designed to evaluate the efficacy of the simultaneous application of 3d-conformal radiotherapy and chemotherapy with hydroxyurea (HU).

PATIENTS AND METHODS

Twenty-one patients with recurrent or progressive meningiomas (13 benign, 4 atypical and malignant, 4 with unproven histology) received treatment by fractionated 3d-conformal radiation (55.8-59.4 Gy) and concurrent HU, administered for a median time of three months with a daily dosage of 20 mg/kg. Response was evaluated using clinical and neuro-imaging data.

RESULTS

Disease stabilization was achieved in 14/21 patients (pts). Three pts had significant improvement of tumor associated neurological symptoms with imaging criteria of minor response. Progression free survival rates 1 year and 2 years after the initiation of radio-chemotherapy were 84% and 77%, respectively. At the time of analysis a total of 6/21 pts presented with progressive disease with a median time to progression of 59 weeks. Documented radio- and chemotherapy associated toxicity was minimal; only one patient discontinued HU treatment due to gastrointestinal symptoms such as anorexia and weight loss.

CONCLUSION

Results obtained in this study indicate that treatment with HU and simultaneous radiotherapy is safe and effective with disease stabilization in the majority of patients. Randomized trials comparing radiosurgery versus radiochemotherapy versus fractionated radiotherapy are warranted.

Pushing the limits of radiotherapy for atypical and malignant meningioma

PURPOSE

The purpose of this study was to report the outcome of an extremely aggressive radiotherapy program in patients with atypical and malignant meningioma (60 Gy at 1.5 Gy per fraction twice daily +/- radiosurgery boost).

METHODS AND MATERIALS

Thirty-six patients received radiotherapy with curative intent between 1984 and 1999 for atypical (27 patients) or malignant (9 patients) meningioma. All patients had a minimum of 2 years follow up.

RESULTS

The overall 5-year local control, cause-specific survival, and absolute survival rates were 45%, 39%, and 36%, respectively. Accelerated hyperfractionated radiotherapy resulted in a local control rate of 45% compared with 50% for patients treated with less aggressive schedules (P = 0.99). A radiosurgery boost did not improve tumor control. The complication rate for those treated with accelerated hyperfractionated radiotherapy was dramatically higher (grade 3-5: 55% vs. 0%, grade 4-5: 27% vs. 0%. both P <0.05).

CONCLUSION

Our data suggests that 50 to 60 Gy delivered with conventional, once-daily fractionation is probably the optimal schedule for atypical and malignant meningioma. More aggressive radiotherapy fractionation schedules and radiosurgery are unlikely to improve outcome.

Bone metastasis of intracranial meningeal hemangiopericytoma

The authors investigated the clinical and radiological features and the treatment strategy for bone metastasis from a rare tumor, intracranial meningeal hemangiopericytoma. The clinical presentations and characteristic imagings were retrospectively reviewed in 15 bony metastatic lesions of four patients with this tumor. All four cases were initially diagnosed as atypical meningioma, and all of the bone metastases developed more than 10 years after the initial intracranial surgery. The common symptom induced by the metastatic lesions was pain. On plain roentgen films and computed tomography (CT), the involved bones showed thinning and expansion. On bone scintigraphy, a "cold-in-hot" appearance was typically observed. The clinical and radiological findings were diagnosed as bone metastasis from intracranial meningeal hemangiopericytoma. The prognosis after bone metastasis was relatively short compared to the long duration before bone metastases, because of the coexistence of other, visceral, metastasis. Combined with effective radiation therapy, surgical intervention for bone metastasis of this tumor should be carefully considered.

Volume reduction in meningiomas after gamma knife surgery

Object.The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment.

Methods.A group of 127 patients with a mean age of 57.1 years (range 9–81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter.

The mean tumor volume was 5.9 cm3(range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11–61 months). The mean prescription dose was 13.8 Gy (range 10–18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) showed a volume increase.

Conclusions.Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.

Volume reduction in meningiomas after gamma knife surgery

Object. The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment.

Methods. A group of 127 patients with a mean age of 57.1 years (range 9–81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter.

The mean tumor volume was 5.9 cm3 (range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11–61 months). The mean prescription dose was 13.8 Gy (range 10–18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) showed a volume increase.

Conclusions. Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.

Radiotherapy after surgery for benign cerebral meningioma

BACKGROUND AND PURPOSE

To compare the outcome from adjuvant and delayed radiotherapy (RT) after surgery in patients with benign cerebral meningioma.

PATIENTS AND METHODS

Between March 1953 and January 2001, 92 patients with benign cerebral meningioma (WHO grade I) were treated with surgery. Forty-eight patients underwent gross total resection (GTR), and 44 patients underwent subtotal resection (STR). Treatments were classified as GTR (n = 48), STR+adjuvant RT (n = 12), STR alone (n = 32). The prognostic factors were assessed as, gender, the Karnofsky performance score (KPS) (> or =90 vs. <90), the extent of surgery, and adjuvant or delayed RT. The endpoints analyzed were progression-free survival (PFS) and overall survival (OS). Overall survival curve of the study population is compared with the age-adjusted expected survival curve for the US population born in 1970.

RESULTS

The median follow-up was 7.7 years. The 5-year PFS and OS rates for all patients were 65 and 93%, respectively. The 5-year PFS rates in patients treated with GTR and STR were 77 and 52%, respectively (P = 0.02). Patients treated with STR+adjuvant RT had significantly better PFS (91%) at 5 years than with STR alone (38%) (P = 0.0005). Gender showed no statistically significant impact on either PFS or OS (P > 0.05). However, multivariate analysis showed the KPS to have a statistically significant effect on OS (P = 0.02). The OS rate was the same across all three treatment groups. The age-adjusted expected survival curve for the US population born in 1970 lay within the confidence intervals for the overall survival curve of the study population.

CONCLUSIONS

Although OS was not affected, adjuvant RT appeared to significantly reduce tumor progression. However, only a prospective randomized trial can adequately determine whether adjuvant or delayed radiotherapy is the better approach in patients with subtotally resected benign meningioma.