A systematic review of brain metastases from lung cancer using magnetic resonance neuroimaging: Clinical and technical aspects

INTRODUCTION

Brain metastases (BMs) are common in lung cancer (LC) and are associated with poor prognosis. Magnetic resonance imaging (MRI) plays a vital role in the detection, diagnosis and management of BMs. This review summarises recent advances in MRI techniques for BMs from LC.

METHODS

This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive literature search was conducted in three electronic databases: PubMed, Scopus and the Web of Science. The search was limited to studies published between January 2000 and March 2023. The quality of the included studies was evaluated using appropriate tools for different study designs. A narrative synthesis was carried out to describe the key findings of the included studies.

RESULTS

Sixty-five studies were included. Standard MRI sequences such as T1-weighted (T1w), T2-weighted (T2w) and fluid-attenuated inversion recovery (FLAIR) were commonly used. Advanced techniques included perfusion-weighted imaging (PWI), diffusion-weighted imaging (DWI) and radiomics analysis. DWI and PWI parameters could distinguish tumour recurrence from radiation necrosis. Radiomics models predicted genetic mutations and the risk of BMs. Diagnostic accuracy was improved with deep learning (DL) approaches. Prognostic factors such as performance status and concurrent chemotherapy impacted survival.

CONCLUSION

Advanced MRI techniques and specialised MRI methods have emerging roles in managing BMs from LC. PWI and DWI improve diagnostic accuracy in treated BMs. Radiomics and DL facilitate personalised prognosis and treatment. Magnetic resonance imaging plays a key role in the continuum of care for BMs of patients with LC, from screening to treatment monitoring.

Comparison of Staged Stereotactic Radiosurgery and Fractionated Stereotactic Radiotherapy in Patients with Brain Metastases > 2 cm without Prior Whole Brain Radiotherapy: A Systematic Review and Meta-Analysis

OBJECTIVE

To compare fractionated stereotactic radiotherapy (FSRT) with staged stereotactic radiosurgery (SSRS) in patients with brain metastases >2 cm without prior whole brain radiotherapy.

METHODS

In this systematic review and meta-analysis, PubMed, Scopus, Web of Science, Embase, and Cochrane were searched to include studies that evaluated FSRT and/or SSRS for brain metastases >2 cm or 4 cm3 in adult patients with a known primary malignancy and no prior history of whole brain radiotherapy. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed and an indirect random-effect meta-analyses was conducted to compare treatment outcomes between the two modalities.

RESULTS

A total of 10 studies were included, comprising 612 (778 metastases) and 250 patients (265 metastases) in the SSRS and FSRT groups, respectively. The SSRS group had significantly older patients (66.6 ± 17.51 years vs. 62.37 ± 37.89 years; P = 0.029) with lower rate of control of primary disease (11.59% vs. 78.7%, P < 0.00001), and more patients with Karnofsky performance status ≥70 at baseline (92.81% vs. 88.56%; P = 0.045). FSRT was associated with a statistically nonsignificant but clinically important lower 12-month overall survival (44.75% [95% confidence interval [CI]: 30.48%-59.95%] vs. 53.25% [95%CI: 45.15%-61.19%], P = 0.1615) and higher rate of salvage radiotherapy (18.18% [95%CI: 8.75%-34%] vs. 12.27% [95%CI: 5.98%-23.53%], P = 0.0841). Both groups had comparable rates of local tumor control, mortality, tumor progression, recurrence, neurological death, and 6-month overall survival.

CONCLUSIONS

SSRS and FSRT were found to be comparable for treating brain metastases >2 cm not previously irradiated. Given the paucity of such studies, trials directly comparing the two treatment strategies are warranted to support these findings.

Fractionated versus staged gamma knife radiosurgery for mid-to-large brain metastases: a propensity score-matched analysis

PURPOSE

To compare treatment results between fractionated gamma knife radiosurgery (f-GKRS) and staged gamma knife radiosurgery (s-GKRS) for mid-to-large brain metastases (BMs).

METHODS

We retrospectively analyzed data of patients with medium (4-10 mL) to large (> 10 mL) BMs who underwent s-GKRS or f-GKRS between March 2008 and September 2022. Patients were treated with (i) s-GKRS before May 2018 and (ii) f-GKRS after May 2018. Patients who underwent follow-up magnetic resonance imaging at least once were enrolled. Case-matched studies were conducted by applying propensity score matching to minimize treatment selection bias and potential confounding. Local control (LC) was set as the primary endpoint and overall survival (OS) as the secondary endpoint.

RESULTS

This study included 129 patients with 136 lesions and 70 patients with 78 lesions who underwent s-GKRS and f-GKRS, respectively. Overall, 124 lesions (62 lesions in each group) were selected in the case-matched group. No differences were observed in the 6-month and 1-year cumulative incidences of LC failure between the s-GKRS and f-GKRS groups (15.6% vs. 15.9% at 6 months and 25.6% vs. 25.6% at 1 year; p = 0.617). One-year OS rates were 62.6% (95% confidence interval [CI]: 45.4-75.7%) and 73.9% (95% CI: 58.8-84.2%) in the s-GKRS and f-GKRS groups, respectively. The post-GKRS median survival time was shorter in the s-GKRS group than in the f-GKRS group (17 vs. 36 months), without significance (p = 0.202).

CONCLUSIONS

This is the first study to compare f-GKRS and s-GKRS in large BMs. Fractionation is as effective as staged GKRS for treating mid-to-large BMs.

Direct dosimetric comparison of linear accelerator vs. Gamma Knife fractionated stereotactic radiotherapy (fSRT) of large brain tumors

The purpose of this study was to directly compare the plan quality of Gamma Knife (GK) (Elekta, Stockholm, Sweden)- vs linear accelerator (LINAC)-based delivery techniques for fractionated stereotactic radiotherapy (fSRT) of large brain metastases. Eighteen patients with clinical target volumes (CTVs) larger than 9.5 cc were selected to generate comparative plans for the prescription dose of 9 Gy × 3 fractions, utilizing the Eclipse (Varian, Palo Alto, US) vs Leksell GammaPlan (LGP) (Elekta, Stockholm, Sweden) treatment planning systems (TPS). Each GK plan was first developed using LGP's automatic planning, followed by manual adjustments/refinements. The same MRI and structures, including CTVs and organs at risk, were then DICOM-transferred to the Eclipse TPS. Volumetric Modulated Arc Therapy (VMAT) and Dynamic Conformal Arc (DCA) plans for a Truebeam, with high-definition multi-leaf collimators (MLCs), were developed on these MR images and structures using a single isocenter and 3 non-coplanar arcs. No planning target volume (PTV) margins were added, and no heterogeneity correction was used for either TPS. GK plans were prescribed to the 50% isodose line, and Eclipse VMAT and DCA plans allowed a maximum dose up to 170% and ∼125%, respectively. Gradient index (GI), Paddick Conformity Index (PCI), V_20GyRind, and V_4GyRind of all 3 techniques were calculated and compared. One-way analysis of variance (ANOVA) was performed to determine the statistical significance of the differences of these planning indices for the 3 planning techniques. A total of eighteen treatment targets were analyzed. Median CTV volume was 14.4 cc (range 9.5 cc - 55.9 cc). Mean ± standard deviation of PCI were 0.85 ± 0.03, 0.90 ± 0.03, and 0.72 ± 0.11 for GK, VMAT and DCA plans, respectively. They were respectively 2.64 ± 0.17, 2.46 ± 0.18, and 2.83 ± 0.48 for GI; 15.33 ± 8.45 cc, 10.47 ± 4.32 cc and 23.51 ± 16 cc for V_20GyRind; and 316.28 ± 138.35 cc, 317.81 ± 108.21 cc, and 394.85 ± 142.16 cc for V_4GyRind. The differences were statistically significant with p < 0.01 for all indices, except for V_4GyRind (p > 0.129). In conclusion, a direct dosimetric comparison using the same MRI scan and contours was performed to evaluate the plan quality of various fSRT delivery techniques for CTV > 9.5 cc. LINAC VMAT plans provided the best dosimetric outcome in regard to PCI, GI, and V_20GyRind. GK outcomes were similar to LINAC VMAT plans while LINAC DCA outcomes were significantly worse. Even though GK has a smaller physical penumbra, LINAC VMAT outperformed GK in this study due to enhanced penumbra sharpening and better beam optimization.

Treatment of breast cancer brain metastases: radiotherapy and emerging preclinical approaches

The breast is one of the common primary sites of brain metastases (BM). Radiotherapy for BM from breast cancer may include whole brain radiation therapy (WBRT), stereotactic radiosurgery (SRS), and stereotactic radiotherapy (SRT), but a consensus is difficult to reach because of the wide and varied protocols, indications, and outcomes of these interventions. Overall, dissemination of disease, patient functional status, and tumor size are all important factors in the decision of treatment with WBRT or SRS. Thus far, previous studies indicate that WBRT can improve tumor control compared to SRS, but increase side effects, however no randomized trials have compared the efficacy of these therapies in BM from breast cancer. Therapies targeting long non-coding RNAs and transcription factors, such as MALAT1, HOTAIR, lnc-BM, TGL1, and ATF3, have the potential to both prevent metastatic spread and treat BM with improved radiosensitivity. Given the propensity for HER2+ breast cancer to develop BM, the above-mentioned cell lines may represent an important target for future investigations, and the development of everolimus and pyrotinib are equally important.

Dose-Response Effect and Dose-Toxicity in Stereotactic Radiotherapy for Brain Metastases: A Review

Simple Summary

Brain metastases are one of the most frequent complications for cancer patients. Stereotactic radiosurgery is considered a cornerstone treatment for patients with limited brain metastases and the ideal dose and fractionation schedule still remain unknown. The aim of this literature review is to discuss the dose-effect relation in brain metastases treated by stereotactic radiosurgery, accounting for fractionation and technical considerations.

Abstract

For more than two decades, stereotactic radiosurgery has been considered a cornerstone treatment for patients with limited brain metastases. Historically, radiosurgery in a single fraction has been the standard of care but recent technical advances have also enabled the delivery of hypofractionated stereotactic radiotherapy for dedicated situations. Only few studies have investigated the efficacy and toxicity profile of different hypofractionated schedules but, to date, the ideal dose and fractionation schedule still remains unknown. Moreover, the linear-quadratic model is being debated regarding high dose per fraction. Recent studies shown the radiation schedule is a critical factor in the immunomodulatory responses. The aim of this literature review was to discuss the dose–effect relation in brain metastases treated by stereotactic radiosurgery accounting for fractionation and technical considerations. Efficacy and toxicity data were analyzed in the light of recent published data. Only retrospective and heterogeneous data were available. We attempted to present the relevant data with caution. A BED10 of 40 to 50 Gy seems associated with a 12-month local control rate >70%. A BED10 of 50 to 60 Gy seems to achieve a 12-month local control rate at least of 80% at 12 months. In the brain metastases radiosurgery series, for single-fraction schedule, a V12 Gy < 5 to 10 cc was associated to 7.1–22.5% radionecrosis rate. For three-fractions schedule, V18 Gy < 26–30 cc, V21 Gy < 21 cc and V23 Gy < 5–7 cc were associated with about 0–14% radionecrosis rate. For five-fractions schedule, V30 Gy < 10–30 cc, V 28.8 Gy < 3–7 cc and V25 Gy < 16 cc were associated with about 2–14% symptomatic radionecrosis rate. There are still no prospective trials comparing radiosurgery to fractionated stereotactic irradiation.

The evolving role of neurosurgery for central nervous system metastases in the era of personalized cancer therapy

Recent therapeutic advances involving the use of systemic targeted treatments and immunotherapeutic agents in patients with advanced cancers have translated into improved survival rates. Despite the emergence of such promising pharmacological therapies and extended survival, the frequency of metastases in the central nervous system has steadily increased. Effective medical and surgical therapies are available for many patients with brain metastases and need to be incorporated into multi-disciplinary care protocols. The role of neurosurgeons is evolving within these multi-disciplinary care teams. Surgical resection of brain metastases can provide immediate relief from neurological symptoms due to large lesions and provides the histopathological diagnosis in cases of no known primary malignancy. In situations where immunotherapy is part of the oncological treatment plan, surgery may be proposed for expeditious relief of edema to remove the need for steroids. In patients with multiple brain metastases and mixed response to therapeutics or radiosurgery, tumour resampling allows tissue analysis for druggable targets or to distinguish radiation effects from progression. Ventriculo-peritoneal shunting may improve quality of life in patients with hydrocephalus associated with leptomeningeal tumour dissemination and may allow for time to administer more therapy thus prolonging overall survival. Addressing the limited efficacy of many oncological drugs for brain metastases due to insufficient blood-brain barrier penetrance, clinical trial protocols in which surgical specimens are analysed after pre-surgical administration of therapeutics offer pharmacodynamic insights. Comprehensive neurosurgical assessment remains an integral element of multi-disciplinary oncological care of patients with brain metastases and is integral to tumour biology research and therapeutic advancement.

Single-fraction versus hypofractionated gamma knife radiosurgery for small metastatic brain tumors

Stereotactic radiosurgery (SRS) has become a standard of care for the treatment of metastatic brain tumors (METs). Although a better balance of tumor control and toxicity of hypofractionated SRS (hfSRS) compared with single-fraction SRS (sfSRS) was demonstrated in large METs, there is no data comparing two approaches for small METs (< 4 cm³). It was aimed to compare clinical outcomes between sfSRS versus hfSRS Gamma Knife radiosurgery (GKRS) in a series of patients with unresected, small METs. Patients (n = 208) treated with sfGKRS or hfGKRS between June 2017 and May 2020 were retrospectively examined in a single center. The co-primary endpoints of local control (LC) and toxicity were estimated by applying the Kaplan-Meier method. Multivariate analysis using Cox proportional hazards (HR) modeling was used to assess the effect of independent variables on the outcomes. The actuarial LC rate was 99.7% at six months and 98.8% at 18 months in the sfGKRS group, and 99.4% and 94.3% in the hfGKRS group (p = 0.089), respectively. In multivariate analysis, MET volume (p = 0.023, HR 2.064) and biologically effective dose (BED₁₀) (p < 0.0001, HR 0.753) was associated with LC. In total, treatment-related toxicity was observed in 13 (8.7%) patients during a median period of 10 weeks (range 1-31). Radiation necrosis was observed in four patients (1.9%), and all patients were in the sfGKRS group (p = 0.042). Only the maximum dose was associated with toxicity (p = 0.032, HR 1.047). Our current results suggest that hfGKRS is advantageous and beneficial also in patients with unresected, small METs.

Hypofractionated frameless gamma knife radiosurgery for large metastatic brain tumors

Hypofractionated stereotactic radiosurgery has become an alternative for metastatic brain tumors (METs). We aimed to analyze the efficacy and safety of frameless hypofractionated Gamma Knife radiosurgery (hfGKRS) in the management of unresected, large METs. All patients who were managed with hfGKRS for unresected, large METs (> 4 cm³) between June 2017 and June 2020 at a single center were reviewed in this retrospective study. Local control (LC), progression-free survival (PFS), overall survival (OS), and toxicities were investigated. A total of 58 patients and 76 METs with regular follow-up were analyzed. LC rate was 98.5% at six months, 96.0% at one year, and 90.6% at 2 years during a median follow-up of 12 months (range, 2-37). The log-rank test indicated no difference in the distribution of LC for any clinical or treatment variable. PFS was 86.7% at 6 months, 66.6% at 1 year, and 58.5% at 2 years. OS was 81% at 6 months, 63.6% at one year, and 50.7% at 2 years. On the log-rank test, clinical parameters such as control status of primary cancer, presence of extracranial metastases, RTOG-RPA class, GPA group, and ds-GPA group were significantly associated with PFS and OS. Patients presented with grade 1 (19.0%), grade 2 (3.5%) and grade 3 (5.2%) side effects. Radiation necrosis was not observed in any patients. Our current results suggest that frameless hfGKRS for unresected, large METs is a rational alternative in selected patients with promising results.

Dosimetric comparison of Gamma Knife® IconTM and linear accelerator-based fractionated stereotactic radiotherapy (FSRT) plans for the re-irradiation of large (>14 cm3) recurrent glioblastomas

Our objective is to investigate dosimetric differences between clinically deliverable Gamma Knife^® (GK) Icon™ and linac-based FSRT plans on the basis of normal brain dose sparing for large (>14 cm³) recurrent glioblastomas (GBM). Sixteen patients with large, recurrent GBM were treated using re-irradiation via linac-based FSRT, 35 Gy in 10 fractions. For each patient, a new GK FSRT plan was created in Leksell GammaPlan^® V11 (LGP). To maintain clinical deliverability, the LGP optimization included a planning goal of treatment time <20 minutes per fraction. Dosimetric comparison of coverage and normal brain dose between the linac and GK treatment plans was performed in MIM. The GK FSRT plans had significantly (p < 0.05) lower mean normal brain dose values (-8.85%), mean values of normal brain V20 (-32.4%) and V12 (-25.9%), and a lower mean V4 (-10.0%). GK FSRT plans have the potential to reduce the risk of radiation-related toxicities.

The Judicious Use of Stereotactic Radiosurgery and Hypofractionated Stereotactic Radiotherapy in the Management of Large Brain Metastases

Simple Summary

Brain metastases are the most common cause of cancerous brain tumors in adults. Large brain metastases are an especially difficult clinical scenario as patients often have debilitating symptoms from these tumors, and large tumors are more difficult to control with traditional single treatment radiation regimens alone or after surgery. Hypofractionated stereotactic radiotherapy is a novel way to deliver the higher doses of radiation to control large tumors either after surgery (most common), alone (common), or potentially before surgery (uncommon). Herein, we describe how delivering high doses over three or five treatments may improve tumor control and decrease complication rates compared to more traditional single treatment regimens for brain metastases larger than 2 cm in maximum dimension.

Abstract

Brain metastases are the most common intracranial malignant tumor in adults and are a cause of significant morbidity and mortality for cancer patients. Large brain metastases, defined as tumors with a maximum dimension >2 cm, present a unique clinical challenge for the delivery of stereotactic radiosurgery (SRS) as patients often present with neurologic symptoms that require expeditious treatment that must also be balanced against the potential consequences of surgery and radiation therapy—namely, leptomeningeal disease (LMD) and radionecrosis (RN). Hypofractionated stereotactic radiotherapy (HSRT) and pre-operative SRS have emerged as novel treatment techniques to help improve local control rates and reduce rates of RN and LMD for this patient population commonly managed with post-operative SRS. Recent literature suggests that pre-operative SRS can potentially half the risk of LMD compared to post-operative SRS and that HSRT can improve risk of RN to less than 10% while improving local control when meeting the appropriate goals for biologically effective dose (BED) and dose-volume constraints. We recommend a 3- or 5-fraction regimen in lieu of SRS delivering 15 Gy or less for large metastases or resection cavities. We provide a table comparing the BED of commonly used SRS and HSRT regimens, and provide an algorithm to help guide the management of these challenging clinical scenarios.

Retrospective analysis of hypofractionated stereotactic radiotherapy for tumors larger than 2 cm

Stereotactic radiosurgery for large brain metastases (BM) not amenable to surgical resection is associated with limited local control and neurotoxicity, while hypofractionated stereotactic radiotherapy (HFSRT) has emerged as a promising option. We retrospectively evaluated 61 patients with BM larger than 2 cm in the maximum diameter, who were treated with HFSRT (mainly 35 Gy/5 fractions) in our center between 2006–2016, focusing on the effect of BM size on outcomes. Eligible patients were divided according to the maximum BM diameter (group A [23 patients]: ≥3 cm, group B [22 patients]: <3 cm) to assess the relationship between tumor size and prognosis or safety. The primary outcome was the local control rate (LCR), and secondary outcomes were the response rate (RR), brain progression-free survival (BPFS), median survival time (MST), and radionecrosis (RN). Univariate and multivariate analyses for LCR were conducted using Cox’s proportional hazards model. In the 45 eligible patients (58 lesions) enrolled in this study, the RR was 86.4% with an overall LCR of 64.7% at 12 months (67.1% for group A and 61.5% for group B [p = 0.45]). The median BPFS and MST were 11.6 and 14.2 months, respectively. Univariate analyses revealed that female patients and gynecological cancer patients had poorer LCR, but they were not significantly independent prognostic factors (p = 0.06, 0.09, respectively). Two patients (4.4%) experienced RN that was detected more than 4 years after HFSRT. We conclude that HFSRT is safe for large BM but further studies are needed to determine optimal doses and fractions.

Fractionated stereotactic radiosurgery for locally recurrent brain metastases after failed stereotactic radiosurgery

AIMS AND BACKGROUND

There is scant data on the utility of repeated radiosurgery for management of locally recurrent brain metastases after upfront stereotactic radiosurgery (SRS). Most studies have used single-fraction SRS for repeated radiosurgery, and the use of fractionated stereotactic radiosurgery (f-SRS) in this setting has been poorly addressed. In this study, we assessed the utility of f-SRS for the management of locally recurrent brain metastases after failed upfront single-fraction SRS and report our single-center experience.

METHODS AND STUDY DESIGN

A total of 30 patients receiving f-SRS for locally recurrent brain metastases after upfront single-fraction SRS at our department between September 2011 and September 2017 were retrospectively evaluated for local control (LC), toxicity, and overall survival outcomes.

RESULTS

Median age and Karnofsky performance status were 57 (range: 38-78 years) and 80 (range: 70-100) at repeated radiosurgery (SRS2). The median time interval between the two radiosurgery applications was 13.5 months (range: 3.7-49 months). LC after SRS2 was 83.3%. Radionecrosis developed in 4 of the 30 lesions after SRS2, and total rate of radionecrosis was 13.3%. Statistical analysis revealed that the volume of planning target volume (PTV) at SRS2 was significantly associated with radionecrosis (P = 0.014). The volume of PTV was >13 cm³ at SRS2 in all patients with radionecrosis.

CONCLUSION

A repeated course of radiosurgery in the form of f-SRS may be a viable therapeutic option for the management of locally recurrent brain metastases after failed upfront SRS with high LC rates and an acceptable toxicity profile despite the need for further supporting evidence.

Tailored Treatment Options for Patients with Brain Metastases by a Relocatable Frame System with Gamma Knife Radiosurgery

OBJECTIVE

To report on our experience with the Elekta Extend system, a relocatable frame system used in patients with brain metastases for single-session, hypofractionated, or staged hypofractionated Gamma Knife radiosurgery (GKRS); and the evaluation of its efficacy.

METHODS

From March 2014 to September 2016, 856 patients with brain metastases underwent GKRS at our hospital. Of them, 35 patients who were retrospectively investigated, were selected for treatment with GKRS using the relocatable frame system. Individualized treatment strategy was chosen according to prior treatment history, number, size and location of tumor, or tumor harboring gene mutation.

RESULTS

Thirty-two (91.4%) patients underwent treatment with hypofractionated GKRS or staged hypofractionated GKRS, whereas 3 (8.6%) patients underwent single session GKRS. The mean radial setup difference from the reference measurements was 0.50 ± 0.16 mm. The median follow-up time after GKRS with the Extend system was 12 months (range, 1-45 months). The median overall survival time was 12 months (95% confidence interval 6.43-17.57). On multivariable analysis, performance status and extracranial metastases were independently prognostic factors for overall survival. Radiation necrosis developed in 4 cases (11.4%) during the follow-up period (2 with common terminology criteria for adverse events grade 2 and 2 with its grade 3).

CONCLUSIONS

The relocatable frame system can maintain submillimetric accuracy and provide tailored treatment option with reasonable tumor control and good survival benefits in selected patients with brain metastases. Especially, hypofractionated GKRS or staged hypofractionated GKRS with noninvasive frame is a safe and effective treatment option for large brain metastases or tumor adjacent to eloquent structures.

[Delineation of the surgical bed of operated brain metastases treated with adjuvant stereotactic irradiation: A review]

Stereotactic radiotherapy of the surgical bed of brain metastases is a technique that comes supplant indications of adjuvant whole brain radiotherapy after surgery. After a growing number of retrospective studies, a phase III trial has been presented and validated this indication. However, several criteria such as the dose, the fractionation, the use of a margin and definition of volumes remain to be defined. Our study consisted in making a literature review in order to provide a guideline of delineation of surgical beds of brain metastases, as well as the different modalities of their implementation process.

Impact of 2-staged stereotactic radiosurgery for treatment of brain metastases ≥ 2 cm

OBJECTIVE Stereotactic radiosurgery (SRS) is the primary modality for treating brain metastases. However, effective radiosurgical control of brain metastases ≥ 2 cm in maximum diameter remains challenging and is associated with suboptimal local control (LC) rates of 37%-62% and an increased risk of treatment-related toxicity. To enhance LC while limiting adverse effects (AEs) of radiation in these patients, a dose-dense treatment regimen using 2-staged SRS (2-SSRS) was used. The objective of this study was to evaluate the efficacy and toxicity of this treatment strategy. METHODS Fifty-four patients (with 63 brain metastases ≥ 2 cm) treated with 2-SSRS were evaluated as part of an institutional review board-approved retrospective review. Volumetric measurements at first-stage stereotactic radiosurgery (first SSRS) and second-stage SRS (second SSRS) treatments and on follow-up imaging studies were determined. In addition to patient demographic data and tumor characteristics, the study evaluated 3 primary outcomes: 1) response at first follow-up MRI, 2) time to local progression (TTP), and 3) overall survival (OS) with 2-SSRS. Response was analyzed using methods for binary data, TTP was analyzed using competing-risks methods to account for patients who died without disease progression, and OS was analyzed using conventional time-to-event methods. When needed, analyses accounted for multiple lesions in the same patient. RESULTS Among 54 patients, 46 (85%) had 1 brain metastasis treated with 2-SSRS, 7 patients (13%) had 2 brain metastases concurrently treated with 2-SSRS, and 1 patient underwent 2-SSRS for 3 concurrent brain metastases ≥ 2 cm. The median age was 63 years (range 23-83 years), 23 patients (43%) had non-small cell lung cancer, and 14 patients (26%) had radioresistant tumors (renal or melanoma). The median doses at first and second SSRS were 15 Gy (range 12-18 Gy) and 15 Gy (range 12-15 Gy), respectively. The median duration between stages was 34 days, and median tumor volumes at the first and second SSRS were 10.5 cm³ (range 2.4-31.3 cm³) and 7.0 cm³ (range 1.0-29.7 cm³). Three-month follow-up imaging results were available for 43 lesions; the median volume was 4.0 cm³ (range 0.1-23.1 cm³). The median change in volume compared with baseline was a decrease of 54.9% (range -98.2% to 66.1%; p < 0.001). Overall, 9 lesions (14.3%) demonstrated local progression, with a median of 5.2 months (range 1.3-7.4 months), and 7 (11.1%) demonstrated AEs (6.4% Grade 1 and 2 toxicity; 4.8% Grade 3). The estimated cumulative incidence of local progression at 6 months was 12% ± 4%, corresponding to an LC rate of 88%. Shorter TTP was associated with greater tumor volume at baseline (p = 0.01) and smaller absolute (p = 0.006) and relative (p = 0.05) decreases in tumor volume from baseline to second SSRS. Estimated OS rates at 6 and 12 months were 65% ± 7% and 49% ± 8%, respectively. CONCLUSIONS 2-SSRS is an effective treatment modality that resulted in significant reduction of brain metastases ≥ 2 cm, with excellent 3-month (95%) and 6-month (88%) LC rates and an overall AE rate of 11%. Prospective studies with larger cohorts and longer follow-up are necessary to assess the durability and toxicities of 2-SSRS.

Fractionated Stereotactic Gamma Knife Radiosurgery for Large Brain Metastases: A Retrospective, Single Center Study

PURPOSE

Stereotactic radiosurgery (SRS) is widely used for brain metastases but has been relatively contraindicated for large lesions (>3 cm). In the present study, we analyzed the efficacy and toxicity of hypofractionated Gamma Knife radiosurgery to treat metastatic brain tumors for which surgical resection were not considered as the primary treatment option.

METHODS AND MATERIALS

Thirty-six patients, forty cases were treated with Gamma Knife-based fractionated SRS for three to four consecutive days with the same Leksell frame on their heads. The mean gross tumor volume was 18.3 cm³, and the median dose was 8 Gy at 50% isodose line with 3 fractions for three consecutive days (range, 5 to 11 Gy and 2 to 4 fractions for 2 to 4 consecutive days). Survival rates and prognostic factors were analyzed.

RESULTS

The overall survival rate at one and two years was 66.7 and 33.1%, respectively. The median survival time was 16.2 months, and the local control rate was 90%. RTOG toxicity grade 1 was observed in 3 (8.3%) patients, grade 2 in 1 (2.7%) patient and grade 3 in 1 (2.7%) patient respectively. Radiation necrosis was developed in 1 (2.7%) patient. KPS scores and control of primary disease resulted in significant differences in survival.

CONCLUSIONS

Our findings suggest that consecutive hypofractionated Gamma Knife SRS could be applied to large metastatic brain tumors with effective tumor control and low toxicity rates.

Role of Surgical Resection in Patients with Single Large Brain Metastases: Feasibility, Morbidity, and Local Control Evaluation

OBJECTIVE

The aim of this study was to evaluate the safety and the feasibility of surgery for single large brain metastases.

METHODS

This retrospective study included 69 patients. All received a "supramarginal resection" according to functional boundaries, defined as a microsurgical excision with an extension larger at least 5 mm greater than the enhancing T1-weighted magnetic resonance imaging (MRI) sequence borders with dural attachment radicalization. Hypofractionated stereotactic radiosurgery on the tumor bed, using 30 Gy in 3 fractions, was performed within 1 month after surgery. Clinical outcome was evaluated at 30 days postoperative and by MRI performed every 3 months. The appearance of postoperative neurologic deficits, local control (LC), brain distant progression (BDP), and overall survival were evaluated.

RESULTS

Clinical remission of symptomatology was obtained in 90.5% of patients. None of them had new neurologic deficits or worsening of preoperative functional status. No major complications or cerebrospinal fluid leakage occurred. No residual tumor was detected on postoperative MRI. The median follow-up was 24 months (range 4-33 months). The 1- to 2-year LC was 100%. Twenty-four (29% of) patients had new BDP, and 75% had extracranial progression. The median 1- to 2-year overall survival was 24 months, 91.3% and 73%. At the last observation time, 15 patients (21.7%) were dead and 54 patients (78.3%) were alive.

CONCLUSION

Supramarginal resection along with dural attachment radicalization have proved to be safe and effective for selected patients with single large brain metastases.

Single-Fraction Versus Multifraction (3 × 9 Gy) Stereotactic Radiosurgery for Large (>2 cm) Brain Metastases: A Comparative Analysis of Local Control and Risk of Radiation-Induced Brain Necrosis

PURPOSE

To investigate the local control and radiation-induced brain necrosis in patients with brain metastases >2 cm in size who received single-fraction or multifraction stereotactic radiosurgery (SRS); factors associated with clinical outcomes and the development of brain radionecrosis were assessed.

METHODS AND MATERIALS

Two hundred eighty-nine consecutive patients with brain metastases >2.0 cm who received SRS as primary treatment at Sant'Andrea Hospital, University of Rome Sapienza, Rome, Italy, were analyzed. Cumulative incidence analysis was used to compare local control and radiation-induced brain necrosis between groups from the time of SRS. To achieve a balanced distribution of baseline covariates between treatment groups, a propensity score analysis was used.

RESULTS

The 1-year cumulative local control rates were 77% in the single-fraction SRS (SF-SRS) group and 91% in the multifraction SRS (MF-SRS) group (P=.01). Recurrences occurred in 25 and 11 patients who received SF-SRS or MF-SRS (P=.03), respectively. Thirty-one patients (20%) undergoing SF-SRS and 11 (8%) subjected to MF-SRS experienced brain radionecrosis (P=.004); the 1-year cumulative incidence rate of radionecrosis was 18% and 9% (P=.01), respectively. Significant differences between the 2 groups in terms of local control and risk of radionecrosis were maintained after propensity score adjustment.

CONCLUSIONS

Multifraction SRS at a dose of 27 Gy in 3 daily fractions seems to be an effective treatment modality for large brain metastases, associated with better local control and a reduced risk of radiation-induced radionecrosis as compared with SF-SRS.

Efficacy and Safety of Fractionated Stereotactic Radiosurgery for Large Brain Metastases

Objective

To investigate the efficacy and safety of fractionated stereotactic radiosurgery for large brain metastases (BMs).

Methods

Between June 2011 and December 2013, a total of 38 large BMs >3.0 cm in 37 patients were treated with fractionated Cyberknife radiosurgery. These patients comprised 16 men (43.2%) and 21 women, with a median age of 60 years (range, 38-75 years). BMs originated from the lung (n=19, 51.4%), the gastrointestinal tract (n=10, 27.0%), the breast (n=5, 13.5%), and other tissues (n=3, 8.1%). The median tumor volume was 17.6 cc (range, 9.4-49.6 cc). For Cyberknife treatment, a median peripheral dose of 35 Gy (range, 30-41 Gy) was delivered in 3 to 5 fractions.

Results

With a median follow-up of 10 months (range, 1-37 months), the crude local tumor control (LTC) rate was 86.8% and the estimated LTC rates at 12 and 24 months were 87.0% and 65.2%, respectively. The median overall survival (OS) and progression-free survival (PFS) rates were 16 and 11 months, respectively. The estimated OS and PFS rates at 6, 12, and 18 months were 81.1% and 65.5%, 56.8% and 44.9%, and 40.7% and 25.7%, respectively. Patient performance status and preoperative focal neurologic deficits improved in 20 of 35 (57.1%) and 12 of 17 patients (70.6%), respectively. Radiation necrosis with a toxicity grade of 2 or 3 occurred in 6 lesions (15.8%).

Conclusion

These results suggest a promising role of fractionated stereotactic radiosurgery in treating large BMs in terms of both efficacy and safety.

Outcome of surgical resection for brain metastases and radical treatment of the primary tumor in Chinese non-small-cell lung cancer patients

Purpose

Brain metastasis is the most common complication of brain cancer; nevertheless, primary lung cancer accounts for approximately 20%–40% of brain metastases cases. Surgical resection is the preferred treatment for brain metastases. However, no studies have reported the outcome of surgical resection of brain metastases from non–small-cell lung cancer (NSCLC) in the People’s Republic of China. Moreover, the optimal treatment for primary NSCLC in patients with synchronous brain metastases is hitherto controversial.

Patients and methods

We retrospectively analyzed the cases of NSCLC patients with brain metastases who underwent neurosurgical resection at the Sun Yat-sen University Cancer Center, and assessed the efficacy of surgical resection and the necessity of aggressive treatment for primary NSCLC in synchronous brain metastases patients.

Results

A total of 62 patients, including 47 men and 15 women, with brain metastases from NSCLC were enrolled in the study. The median age at the time of craniotomy was 54 years (range 29–76 years). At the final follow-up evaluation, 50 patients had died. The median OS time was 15.1 months, and the survival rates were 70% and 37% at 1 and 2 years, respectively. The median OS time of synchronous brain metastases patients was 12.5 months. Univariate analysis revealed that radical treatment of primary NSCLC was positively correlated with survival, and it was an independent prognostic factor in the multivariate analysis.

Conclusion

Surgical resection is an effective treatment for brain metastases. Besides craniotomy, radical therapy is necessary for the management of primary NSCLC in patients with synchronous brain metastases.

Treatment outcomes using CyberKnife for brain metastases from lung cancer

We investigated the clinical outcomes following treatment using stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (SRT) for brain metastases from lung cancer. A total of 67 patients with 109 brain metastases from lung cancer treated using CyberKnife between 1998 and 2011 were retrospectively analyzed. SRS (median dose, 24 Gy) was used to treat 79 lesions, and 3-fraction SRT (median dose, 30 Gy) was used to treat 30 lesions. The median follow-up time was 9.4 months (range, 0.4-125 months). The 1-year local control rate was 83.3%, and the 1-year distant brain failure rate was 30.1%. The median survival time was 13.1 months, and the 1- and 3-year overall survival (OS) rates were 54.8% and 25.9%, respectively. On multivariate analysis, three factors were found to be statistically significant predictors of OS: (i) presence of uncontrolled primary disease [hazard ratio (HR) = 3.04; P = 0.002]; (ii) Brinkman index (BI) ≥ 1000 (HR = 2.75; P = 0.007); and (iii) pulmonary metastases (HR = 3.54; P = 0.009). Radionecrosis and worsening of neurocognitive function after radiosurgery were observed in 5 (7%) and 3 (4%) patients, respectively. Our results indicated that SRS/SRT for brain metastases from lung cancer was effective. Uncontrolled primary disease, high BI, and pulmonary metastases at treatment were significant risk factors for OS.

The volumetric response of brain metastases after stereotactic radiosurgery and its post-treatment implications

BACKGROUND

Changes in tumor volume are seen on magnetic resonance imaging within weeks after stereotactic radiosurgery (SRS), but it remains unclear what clinical outcomes early radiological changes portend.

OBJECTIVE

We hypothesized that rapid, early reduction in tumor volume post-SRS is associated with prolonged local control and favorable clinical outcome.

METHODS

A retrospective review of patients treated with CyberKnife SRS for brain metastases at the University of North Carolina from 2007 to 2009 was performed. Patients with at least 1 radiological follow-up, minimal initial tumor volume of 0.1 cm, no previous focal radiation, and no recent whole-brain radiation therapy were eligible for inclusion.

RESULTS

Fifty-two patients with 100 metastatic brain lesions were analyzed and had a median follow-up of 15.6 months (range, 2-33 months) and a median of 2 (range, 1-8) metastatic lesions. In treated metastases in which there was a significant tumor volume reduction by 6 or 12 weeks post-SRS, there was no local progression for the duration of the study. Furthermore, patients with metastases that did not reduce in volume by 6 or 12 weeks post-SRS were more likely to require corticosteroids (P = .01) and to experience progression of neurological symptoms (P = .003).

CONCLUSION

Significant volume reductions of brain metastases measured at either 6 or 12 weeks post-SRS were strongly associated with prolonged local control. Furthermore, early volume reduction was associated with less corticosteroid use and stable neurological symptoms.

Predicting tumor control after resection bed radiosurgery of brain metastases

BACKGROUND

Stereotactic radiosurgery (SRS) to the resection bed of a brain metastasis is an important treatment option.

OBJECTIVE

To identify factors associated with tumor progression after SRS of the resection bed of a brain metastasis and to evaluate patterns of failure for patients who eventually had tumor progression.

METHODS

We performed a retrospective analysis of 120 patients who underwent tumor bed radiosurgery after an initial gross total resection. The mean imaging follow-up time was 55 weeks. The median margin dose was 16 Gy. Forty-seven patients (39.2%) underwent whole-brain radiation therapy before or shortly after SRS.

RESULTS

Local tumor control was achieved in 103 patients (85.8%). Progression-free survival was 96% at 6 months, 87% at 12 months, and 74% at 24 months. Recurrence most commonly occurred deep in the cavity (65%) outside the planned treatment volume (PTV) margin (53%). PTV, cavity diameter, and a margin dose < 16 Gy significantly correlated with local failure. For patients with PTVs ≥ 8.0 cm, local progression-free survival declined to 93% at 6 months, 83% at 12 months, and 65% at 24 months. Development or progression of distant metastases occurred in 40% of patients. Whole-brain radiation therapy was not associated with improved local control.

CONCLUSION

Resection bed SRS for brain metastases provided excellent local control. The cavity PTV is predictive of tumor control. Because failure usually occurs outside the PTV, inclusion of a judicious 2- to 3-mm margin beyond the area of postoperative enhancement may be prudent.

A minimally invasive treatment option for large metastatic brain tumors: long-term results of two-session Gamma Knife stereotactic radiosurgery

Background

Large brain metastases (BM) remain a significant cause of morbidity and death for cancer patients despite current advances in multimodality therapies. The goal of the present study was to evaluate the efficacy and limitations of 2-session Gamma Knife stereotactic radiosurgery (SRS) for patients with large BM.

Methods

This is a prospective, open-label and single arm study analyzing 58 consecutive patients who received 2-session SRS for large BM (≥ 10 mL). The median age was 66 years, and the median Karnofsky performance status (KPS) score was 70. SRS was the initial treatment in 51 large tumors (84%) and was used as salvage after failed prior treatments for 10 tumors (16%). The fraction protocol was 20-30 Gy given in 2 fractions with 3–4 weeks between fractions. Overall survival (OS) and neurological death (ND), local tumor control and KPS were analyzed.

Results

The median follow-up time was 9.0 months. One- and 2-year OS rates were 47% and 20%, respectively. The median OS time was 11.8 months (95% CI: 5.5-15.6). The causes of death were intracranial local progression in 5 cases, meningeal carcinomatosis in 3 and progression of the primary lesion in 39. One- and 2-year ND-free survival rates were 91% and 84%, respectively. In 52 of 61 large BM (85%) with sufficient radiological follow-up data, 6- and 12-month local tumor control rates were 85% and 64%, respectively. The mean KPS improved from 70 at the 1st SRS to 82 at the 2nd; the first follow-up mean KPS was 87 (P < 0.001). Symptomatic radiation injury developed and required conservative treatment in 3 patients (5%).

Conclusions

Long-term follow-up showed that two-session Gamma Knife SRS achieved durable tumor control rates as well as acceptable treatment-related morbidity. This treatment method may potentially merit being offered to patients with large BM who are in poor condition or are otherwise ineligible for standard care.

Five-fraction CyberKnife radiotherapy for large brain metastases in critical areas: impact on the surrounding brain volumes circumscribed with a single dose equivalent of 14 Gy (V14) to avoid radiation necrosis

The efficacy and toxicity of five-fraction CyberKnife radiotherapy were evaluated in patients with large brain metastases in critical areas. A total of 85 metastases in 78 patients, including tumors >30 cm(3) (4 cm in diameter) were treated with five-fraction CyberKnife radiotherapy with a median marginal dose of 31 Gy at a median prescribed isodose of 58%. Changes in the neurological manifestations, local tumor control, and adverse effects were investigated after treatment. The surrounding brain volumes circumscribed with 28.8 Gy (single dose equivalent to 14 Gy: V14) were measured to evaluate the risk of radiation necrosis. Neurological manifestations, such as motor weakness, visual disturbances and aphasia improved in 28 of 55 patients (50.9%). Local tumor control was obtained in 79 of 85 metastases (92.9%) during a median follow-up of eight months. Symptomatic edema occurred in 10 patients, and two of them (2.6%) required surgical resection because of radiation necrosis. The V14 of these patients was 3.0-19.7 cm(3). There were 16 lesions with a V14 of ≥7.0 cm(3), and two of these lesions developed extensive brain edema due to radiation necrosis. None of the patients with a V14 of <7.0 cm(3) exhibited edema requiring surgical intervention. We therefore conclude that a high rate of local tumor control and low rates of complications can be obtained after five-fraction CyberKnife radiotherapy for large metastases in critical areas. The V14 of the surrounding brain is therefore a useful indicator for the risk of radiation necrosis in patients with large metastases.

Fractionated stereotactic radiosurgery for patients with brain metastases

Stereotactic radiosurgery (SRS) delivered in 2-5 fractions (multi-fraction SRS) has been employed in patients with brain metastases as an alternative to single-fraction SRS with the aim to reduce late radiation-induced toxicity while maintaining high local control rate. In the present study we have evaluated the efficacy and toxicity of multi-fraction SRS in patients with 1-3 brain metastases. Between March 2006 and October 2012, 135 patients (63 men and 72 women) with 171 brain metastases have been treated with multi-fraction SRS (3 × 9 Gy or 3 × 12 Gy). At a median follow-up of 11.4 months, 16 lesions recurred locally. The 1- and 2-year local control rates were 88 and 72 %, respectively. The 1- and 2-year survival rates were 57 and 25 %, and respective distant failure rates were 52 and 73 %. Seventy-eight percent of patients succumbed to their extracranial disease and 22 % died of progressive intracranial disease. Multivariate analysis showed that melanoma histology was predictive of local failure (p = 0.02; HR 6.1, 95 % CI 1.5-24). Specifically, the 1-year local control rates were 68 % for melanoma, 92 % for breast carcinoma, and 88 % for NSCLC, respectively. Stable extracranial disease (p = 0.004) and Karnofsky performance status (p = 0.01) were predictive of longer survival. Radiologic changes suggestive of radionecrosis occurred in 12 (7 %) out of 171 lesions, with an actuarial risk of 9 % at 1 year and 17 % at 2 years, respectively. In conclusion, multi-fraction SRS appears to be an effective and safe treatment modality for brain metastases. It may represent an alternative to single-dose SRS for patients with large lesions or lesions located near critical structures.

Large intracranial metastatic tumors treated by Gamma Knife surgery: outcomes and prognostic factors

OBJECT

The use of radiosurgery has been well accepted for treating small to medium-size metastatic brain tumors (MBTs). However, its utility in treating large MBTs remains uncertain due to potentially unfavorable effects such as progressive perifocal brain edema and neurological deterioration. In this retrospective study the authors evaluated the local tumor control rate and analyzed possible factors affecting tumor and brain edema response.

METHODS

The authors defined a large brain metastasis as one with a measurement of 3 cm or more in at least one of the 3 cardinal planes (coronal, axial, or sagittal). A consecutive series of 109 patients with 119 large intracranial metastatic lesions were treated with Gamma Knife surgery (GKS) between October 2000 and December 2012; the median tumor volume was 16.8 cm(3) (range 6.0-74.8 cm(3)). The pre-GKS Karnofsky Performance Status (KPS) score for these patients ranged from 70 to 100. The most common tumors of origin were non-small cell lung cancers (29.4% of cases in this series). Thirty-six patients (33.0%) had previously undergone a craniotomy (1-3 times) for tumor resection. Forty-three patients (39.4%) underwent whole-brain radiotherapy (WBRT) before GKS. Patients were treated with GKS and followed clinically and radiographically at 2- to 3-month intervals thereafter.

RESULTS

The median duration of imaging follow-up after GKS for patients with large MBTs in this series was 6.3 months. In the first follow-up MRI studies (performed within 3 months after GKS), 77 lesions (64.7%) had regressed, 24 (20.2%) were stable, and 18 (15.1%) were found to have grown. Peritumoral brain edema as defined on T2-weighted MRI sequences had decreased in 79 lesions (66.4%), was stable in 21 (17.6%), but had progressed in 19 (16.0%). In the group of patients who survived longer than 6 months (76 patients with 77 MBTs), 88.3% of the MBTs (68 of 77 lesions) had regressed or remained stable at the most recent imaging follow-up, and 89.6% (69 of 77 lesions) showed regression of perifocal brain edema volume or stable condition. The median duration of survival after GKS was 8.3 months for patients with large MBTs. Patients with small cell lung cancer and no previous WBRT had a significantly higher tumor control rate as well as better brain edema relief. Patients with a single metastasis, better KPS scores, and no previous radiosurgery or WBRT were more likely to decrease corticosteroid use after GKS. On the other hand, higher pre-GKS KPS score was the only factor that showed a statistically significant association with longer survival.

CONCLUSIONS

Treating large MBTs using either microsurgery or radiosurgery is a challenge for neurosurgeons. In selected patients with large brain metastases, radiosurgery offered a reasonable local tumor control rate and favorable functional preservation. Exacerbation of underlying edema was rare in this case series. Far more commonly, edema and steroid use were lessened after radiosurgery. Radiosurgery appears to be a reasonable option for some patients with large MBTs.

Motor function after stereotactic radiosurgery for brain metastases in the region of the motor cortex

Object

The authors sought to better define the clinical response of patients who underwent stereotactic radiosurgery (SRS) for brain metastases located in the region of the motor cortex.

Methods

A retrospective analysis was performed in 2026 patients with brain metastasis who underwent SRS with the Gamma Knife between 2002 and 2012, and multiple factors that affect motor function before and after SRS were evaluated. Ninety-four patients with tumors ≥ 1.5 cm in diameter located in or adjacent to the motor strip were identified, including 2 patients with bilateral motor strip metastases.

Results

Motor function improved after SRS in 30 (31%) of 96 cases, remained stable in 48 (50%), and worsened over time in 18 (19%) instances. Forty-seven patients had no motor weakness prior to radiosurgery; 10 (22%) developed new Grade 3/5–4/5 weakness. Thirty (68%) of 44 patients with ≥ 3/5 pre-SRS weakness improved, 6 (14%) remained stable, and 8 (18%) worsened. Three of 5 patients with < 3/5 pre-SRS motor function improved. Motor deficits prior to SRS did not correlate with a worse outcome; however, worse outcomes were associated with larger tumor volumes. The median tumor volume in patients whose function improved or remained stable was 5.3 cm3, but it was 9.2 cm3 in patients who worsened (p < 0.05). Tumor volumes > 9 cm3 were associated with a higher risk of worsening motor function. Adverse radiation effects occurred in 5 patients.

Conclusions

Most intact patients with brain metastases in or adjacent to motor cortex maintained neurological function after SRS, and most patients with symptomatic motor weakness remained stable or improved. Larger tumor volumes were associated with less satisfactory outcomes.

Three-fraction CyberKnife radiotherapy for brain metastases in critical areas: referring to the risk evaluating radiation necrosis and the surrounding brain volumes circumscribed with a single dose equivalence of 14 Gy (V14)

The efficacy and toxicity of three-fraction CyberKnife radiotherapy were evaluated in patients with brain metastases in critical areas. One hundred and fifty-nine metastases in 145 patients including tumors >10 cm(3) were treated with three-fraction CyberKnife radiotherapy with a median marginal dose of 27 Gy at a median prescribed isodose of 60%. Changes in the neurological manifestations, local tumor control and adverse effects were investigated after treatment. The surrounding brain volumes circumscribed with 23.1 Gy (single dose equivalence of 14 Gy: V14) were measured to evaluate the risk of adverse effects. Neurological manifestations, such as motor weakness, visual disturbances and aphasia improved in 26 of 97 patients (26.8%). Local tumor control was obtained in 137 of 143 metastases (95.8%) during a median follow-up of 7 months. Nine patients had symptomatic edema and three of them (2.1%) required surgical resection because of radiation necrosis. The V14 of these patients was 4.6-31.5 cm(3). There were 35 lesions with a V14 of 7 cm(3) or more and three of them developed extensive brain edema due to radiation necrosis. None of the patients with a V14 of <7 cm(3) exhibited edema requiring an operation. We therefore conclude that a high rate of local tumor control and low rates of complications are obtained after three-fraction CyberKnife radiotherapy for metastases in critical areas. The V14 of the surrounding brain therefore seems to be a useful indicator for the risk evaluation of radiation necrosis in patients with larger metastases.

Multidose stereotactic radiosurgery (9 Gy × 3) of the postoperative resection cavity for treatment of large brain metastases

PURPOSE

To evaluate the clinical outcomes with linear accelerator-based multidose stereotactic radiosurgery (SRS) to large postoperative resection cavities in patients with large brain metastases.

METHODS AND MATERIALS

Between March 2005 to May 2012, 101 patients with a single brain metastasis were treated with surgery and multidose SRS (9 Gy × 3) for large resection cavities (>3 cm). The target volume was the resection cavity with the inclusion of a 2-mm margin. The median cavity volume was 17.5 cm(3) (range, 12.6-35.7 cm(3)). The primary endpoint was local control. Secondary endpoints were survival and distant failure rates, cause of death, performance measurements, and toxicity of treatment.

RESULTS

With a median follow-up of 16 months (range, 6-44 months), the 1-year and 2-year actuarial survival rates were 69% and 34%, respectively. The 1-year and 2-year local control rates were 93% and 84%, with respective incidences of new distant brain metastases of 50% and 66%. Local control was similar for radiosensitive (non-small cell lung cancer and breast cancer) and radioresistant (melanoma and renal cell cancer) brain metastases. On multivariate Cox analysis stable extracranial disease, breast cancer histology, and Karnofsky performance status >70 were associated with significant survival benefit. Brain radionecrosis occurred in 9 patients (9%), being symptomatic in 5 patients (5%).

CONCLUSIONS

Adjuvant multidose SRS to resection cavity represents an effective treatment option that achieves excellent local control and defers the use of whole-brain radiation therapy in selected patients with large brain metastases.

Radionecrosis induced by stereotactic radiosurgery of brain metastases: results of surgery and outcome of disease

Sterotactic radiosurgery (SRS) is an effective and commonly employed therapy for metastatic brain tumors. Among complication of this treatment, symptomatic focal cerebral radionecrosis (RN) occurs in 2-10 % of cases. The large diffusion of combined therapies as SRS followed by WBRT and/or CHT, has significantly amplified the number of patients who potentially might be affected by this pathology and neurosurgeons are increasingly called to treat suspected area of RN. Results of surgery of RN in patients with brain metastases are rarely reported in literature, a standardization of diagnostic work-up to correctly identify RN is still lacking and the timing and indications in favour of surgical therapy over medical treatments are not clear as well. In this retrospective study, we review current concept related to RN and analyze the outcome of surgical treatment in a series of 15 patients previously submitted to SRS for brain metastases and affected by suspected radionecrotic lesions. After surgery, all patients except one neurologically improved. No intra-operative complications occurred. Brain edema improved in all patients allowing a reduction or even suspension of corticosteroid therapy. Pure RN was histologically determined in 7 cases; RN and tumor recurrence in the other 8. Overall median survival was 19 months. An aggressive surgical attitude may be advisable in symptomatic patients with suspected cerebral RN, to have histologic confirmation of the lesion, to obtain a long-lasting relief from the mass effect and brain edema and to improve the overall quality of life, sparing a prolonged corticosteroid therapy.

Local progression and pseudo progression after single fraction or fractionated stereotactic radiotherapy for large brain metastases. A single centre study

PURPOSE

The 1-year local control rates after single-fraction stereotactic radiotherapy (SRT) for brain metastases > 3 cm diameter are less than 70%, but with fractionated SRT (FSRT) higher local control rates have been reported. The purpose of this study was to compare our treatment results with SRT and FSRT for large brain metastases.

MATERIALS AND METHODS

In two consecutive periods, 41 patients with 46 brain metastases received SRT with 1 fraction of 15 Gy, while 51 patients with 65 brain metastases received FSRT with 3 fractions of 8 Gy. We included patients with brain metastases with a planning target volume of > 13 cm(3) or metastases in the brainstem.

RESULTS

The minimum follow-up of patients still alive was 22 months. Comparing 1 fraction of 15 Gy  with 3 fractions of 8 Gy, the 1-year rates of freedom from any local progression (54% and 61%, p = 0.93) and pseudo progression (85% and 75%, p = 0.25) were not significantly different. Overall survival rates were also not different.

CONCLUSION

The 1-year local progression and pseudo progression rates after 1 fraction of 15 Gy or 3 fractions of 8 Gy for large brain metastases and metastases in the brainstem are similar. For better local control rates, FSRT schemes with a higher biological equivalent dose may be necessary.

Hypofractionated stereotactic radiotherapy for brain metastases larger than three centimeters

Background

To evaluate the efficacy and outcomes of hypofractionated stereotactic radiotherapy (HSRT) for brain metastases > 3 cm.

Methods

From March 2003 to October 2009, 40 patients with brain metastases larger than 3 cm were treated by HSRT. HSRT was applied in 29 patients for primary treatment and in 11 patients for rescue. Single brain metastasis was detected in 21 patients. Whole brain radiotherapy was incorporated into HSRT in 10 patients for primary treatment. HSRT boosts were applied in 23 patients. The diameters of the brain metastases ranged from 3.1 to 5.5 cm (median, 4.1 cm). The median prescribed dose (not including HSRT boosts) was 40 Gy (range, 20-53 Gy) with a median of 10 fractions (range, 4-15 fractions) to the 90% isodose line. The median dose of the boost was 20 Gy (range, 10-35 Gy) in 4 fractions (range, 2-10 fractions).

Result

The median overall survival time was 15 months. The overall survival and local control rate at 12 months was 55.3% and 94.2%, respectively. Four patients experienced local progression of large brain metastases. Nine patients died of intracranial disease progression. One patient died of radiation necrosis with brain edema.

Conclusion

HSRT was a safe and effective treatment for patients with brain metastases ranged from 3.1 to 5.5 cm. Dose escalation of HSRT boost may improve local control with an acceptable toxicity.