Gamma knife radiosurgery for brainstem metastasis

Efficacy and safety of a "sandwich therapy" based on staged stereotactic radiosurgery and bevacizumab for large brainstem metastases

OBJECTIVE

Gamma Knife stereotactic radiosurgery (SRS) is an effective therapeutic option for unresectable brainstem metastases. Currently, staged stereotactic radiosurgery (SSRS) has become available for large brainstem metastases（≥ 1 cm3） despite the limitation of peritumoral edema. The authors developed the so-called "sandwich therapy" which integrated 2-stage stereotactic radiosurgery (2-SSRS) with bevacizumab for peritumoral edema reduction and local control of large brainstem metastases.

METHODS

42 patients with large brainstem metastases ≥1 cm3 who received 2-SSRS simultaneously with bevacizumab were screened from 2019 to 2021 retrospectively. The first SRS margin doses were 13 Gy (range 11-15) and the second SRS margin doses were 12 Gy (range 11-13), one-time vascular endothelial growth factor (VEGF) inhibitor (bevacizumab) of 3.5-5 mg/kg was administrated intravenously the next day after the first SRS. The median interval between the two sessions of SRS was 6 days. Baseline demographics, clinical and radiology imaging follow-ups were recorded to determine symptomatic improvement, peritumoral edema reduction, local control, and disease progression. Median survival was calculated using Kaplan-Meier analysis. Multivariate analysis was performed to identify prognostic factors.

RESULTS

The "sandwich therapy" was applied to 42 lesions. Significant reductions of tumor volume (p < 0.05) and peritumoral edema volume (p < 0.01) were achieved at the second SRS in comparison to those at the first SRS. The proportion of favorable Karnofsky performance scale (KPS) (≥80 %) increased significantly at early follow-up time points and reached the highest value of 85.7 %. The median survival time was 9.7 months, the median local control duration was 11.3 months. 8 acute adverse events of CTCAE grade 2 and 3 were observed in 6 patients and resolved with palliative treatment. Tyrosine kinase inhibitor (TKI) treatment was identified as a predictive factor for longer survival.

CONCLUSION

The "sandwich therapy" which integrates 2-SSRS with bevacizumab is a safe and effective option for large brainstem metastases.

Brainstem Metastases Treated with Stereotactic Radiosurgery: Masked versus Framed Immobilization

BACKGROUND

Patients with brainstem metastases (BSMs) have minimal surgical options due to high-risk anatomy. To review our efficacy treating BSM using Gamma Knife stereotactic radiosurgery (SRS), we compared results on the basis of the utilization of mask-fixation (MF) or frame-fixation (FF).

METHODS

Data were retrospectively collected for 32 patients. Follow-up data for 49 lesions were analyzed for local control rate (LCR) and objective response rate (ORR).

RESULTS

Primary cancers included lung, breast, and melanoma; most lesions were pontine. MF was used in 18 patients. Average tumor volume was 0.99 cm3 (0.005-13.3 cm3). Thirty-nine lesions were treated with single-fraction 16 Gy. Ten lesions were treated in 3-5 fractions with mean dose of 22.5 Gy. Mean follow-up was 14.2 months (1.2-48.2 months). One-year LCR was 94.7%. ORR at last follow-up did not differ between MF and FF (P = 0.81). Average reduction of lesion volume at 6 and 12 months did not differ between MF and FF (64% vs. 45%, P = 0.77; 70% vs. 77%, P = 0.78). Failure occurred in a pontine colorectal cancer metastasis mask-immobilized for treatment with 14 Gy.

CONCLUSIONS

SRS for BSM achieved high LCR despite variability in tumor size and histology with no significant difference between MF and FF. Although trials have historically excluded patients with BSM, our data support SRS as a safe and efficacious treatment. This is the first study showing that MF provides equivalent, successful outcomes when compared with FF for patients with BSM.

The role of brain radiotherapy for EGFR- and ALK-positive non-small-cell lung cancer with brain metastases: a review

Non-small cell lung cancer (NSCLC) is frequently complicated by central nervous system (CNS) metastases affecting patients' life expectancy and quality. At the present clinical trials including neurosurgery, radiotherapy (RT) and systemic treatments alone or in combination have provided controversial results. CNS involvement is even more frequent in NSCLC patients with EGFR activating mutations or ALK rearrangement suggesting a role of target therapy in the upfront treatment in place of loco-regionals treatments (i.e. RT and/or surgery). So far clinical research has not explored the potential role of accurate brain imaging (i.e. MRI instead of the routine total-body contrast CT and/or PET/CT staging) to identify patients that could benefit of local therapies. Moreover, for patients who require concomitant RT there are no clear guidelines on the timing of intervention with respect to innovative precision medicine approaches with Tyrosine Kinase Inhibitors, ALK-inhibitors and/or immuno-oncological therapies. On this basis the present review describes the therapeutic strategies integrating medical and radiation oncology in patients with metastatic NSCLC (mNSCLC) adenocarcinoma with CNS involvement and EGFR activating mutations or ALK rearrangement.

Adult brainstem glioma differential diagnoses: an MRI-based approach in a series of 68 patients

BACKGROUND

Brainstem gliomas are rare in adults. The diagnosis is often difficult, as some teams still consider brainstem biopsies dangerous and often avoid this procedure. The aim of this study was to describe differential diagnoses that can mimic brainstem glioma, to help clinicians avoid diagnostic and therapeutic mistakes, and to propose a diagnostic algorithm according to radiological presentations.

METHODS

The French network of adult brainstem gliomas (GLITRAD) retrospectively collected all reported cases of differential diagnoses between 2006 and 2017. The inclusion criteria were as follows: age over 18 years, lesion epicenter in the brainstem, radiological pattern suggestive of a glioma and diagnostic confirmation (histopathological or not, depending on the disease).

RESULTS

We identified a total of 68 cases. Most cases (58/68, 85%) presented as contrast-enhancing lesions. The most frequent final diagnosis in this group was metastases in 24/58 (41%), followed by central nervous system lymphoma in 8/58 (14%). Conversely, MRI findings revealed 10/68 nonenhancing lesions. The most frequent diagnosis in this group was demyelinating disease (3/10, 30%).

CONCLUSION

The risk of diagnostic mistakes illustrates the need to consider the more systematic use of a brainstem biopsy when reasonably possible. However, we propose an MRI-based approach to the differential diagnosis of gliomas to limit the risk of misdiagnosis in cases where a biopsy is not a reasonable option.

Efficacy and Safety of Stereotactic Radiosurgery for Brainstem Metastases: A Systematic Review and Meta-analysis

Importance

Owing to the proximity to critical neurologic structures, treatment options for brainstem metastases (BSM) are limited, and BSM growth can cause acute morbidity or death. Stereotactic radiosurgery (SRS) is the only local therapy for BSM, but efficacy and safety of this approach are incompletely understood because patients with BSM are excluded from most clinical trials.

Objective

To perform a systematic review and comparative meta-analysis of SRS studies for BSM in the context of prospective trials of SRS or molecular therapy for nonbrainstem brain metastases (BM).

Data Sources

A comprehensive search of Pubmed/MEDLINE and Embase was performed on December 6, 2019.

Study Selection

English-language studies of SRS for BSM with at least 10 patients and reporting 1 or more outcomes of interest were included. Duplicate studies or studies with overlapping data sets were excluded. Studies were independently evaluated by 2 reviewers, and discrepancies were resolved by consensus. A total of 32 retrospective studies published between 1999 and 2019 were included in the analysis.

Data Extraction and Synthesis

Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed to identify studies. Study quality was assessed using Methodological Index for Non-Randomized Studies criteria. Fixed and random-effects meta-analyses and meta-regressions were performed for the outcomes of interest.

Main Outcomes and Measures

Primary study outcomes included 1-year and 2-year local control and overall survival, objective response rate, symptom response rate, neurological death rate, and rate of grade 3 to 5 toxic effects as described in Common Terminology Criteria for Adverse Events, version 4.0.

Results

The 32 retrospective studies included in the analysis comprised 1446 patients with 1590 BSM that were treated with SRS (median [range] dose, 16 [11-39] Gy; median [range] fractions, 1 [1-13]). Local control at 1 year was 86% (95% CI, 83%-88%; I2 = 38%) in 1410 patients across 31 studies, objective response rate was 59% (95% CI, 47%-71%; I2 = 88%) in 642 patients across 17 studies, and symptom improvement was 55% (95% CI, 47%-63%; I2 = 41%) in 323 patients across 13 studies. Deaths from BSM progression after SRS were rare (19 of 703 [2.7%] deaths across 19 studies), and the neurologic death rate in patients with BSM (24%; 95% CI, 19%-31%; I2 = 62%) was equivalent to the neurologic death rate in patients with BM who were treated on prospective trials. The rate of treatment-related grade 3 to 5 toxic effects was 2.4% (95% CI, 1.5%-3.7%; I2 = 33%) in 1421 patients across 31 studies. These results compared favorably to trials of targeted or immunotherapy for BM, which had a wide objective response rate range from 17% to 56%.

Conclusions and Relevance

Results of this systematic review and meta-analysis show that SRS for BSM was associated with effectiveness and safety and was comparable to SRS for nonbrainstem BM, suggesting that patients with BSM should be eligible for clinical trials of SRS. In this analysis, patients treated with SRS for BSM rarely died from BSM progression and often experienced symptomatic improvement. Given the apparent safety and efficacy of SRS for BSM in the context of acute morbidity or death from BSM growth, consideration of SRS at the time of enrollment on emerging trials of targeted therapy for BM should be considered.

Clinical and radiographic adverse events after Gamma Knife radiosurgery for brainstem lesions: A dosimetric analysis

OBJECTIVES

To analyze the association between dosvolume relationships and adverse events in brainstem lesions treated with Gamma Knife radiosurgery (GKRS).

METHODS

Treatment plans were generated on BrainLab Elements and GammaPlan software. Dosimetric data were analyzed as continuous variables for patients who received GKRS to brain metastases or arteriovenous malformations (AVM) within or abutting the brainstem. Adverse events were classified as clinical and/or radiographic. Logistic and cox regression were used to assess the relationship between dosimetric variables and adverse events.

RESULTS

Sixty-one patients who underwent single fraction GKRS for brain metastases or AVM were retrospectively analyzed. Median age was 62 years (range: 12-92 years) and the median prescription dose was 18 Gy (range: 13-25 Gy). Median follow-up was 6months. Clinical and radiographic complications were seen in ten (16.4%) and 17 (27.9%) patients, respectively. On logistic regression, increasing D_05% was found to be associated with an increased probability of developing a clinical complication post-GKRS (OR: 1.18; 95% CI: 1.01-1.39; p = 0.04). Furthermore, mean brainstem dose (HR: 1.43; 95% CI: 1.05-1.94; p < 0.02), D_05% (HR: 1.09; 95% CI: 1.01-1.18; p = 0.03), and D_95% (HR: 2.37; 95% CI: 0.99-5.67; p = 0.05) were associated with an increased hazard of experiencing post-GKRS complications over time.

CONCLUSIONS

Increasing D_05% to the brainstem is associated with an increased risk of developing clinical complications. Clinicians may consider this parameter in addition to fractionated stereotactic radiation therapy when well-established dose constraints are not met in this patient population. Additional data are needed to further validate these findings.

Cyberknife radiosurgery on the brainstem metastases of non-small cell lung cancer

OBJECTIVE

Management of brainstem metastatic tumor is challenging. This study aimed to evaluate overall survival and quality-of-life in patients with non-small cell lung cancer (NSCLC) brainstem metastases who were treated with the Cyberknife stereotactic radiosurgery.

METHODS

From August 2007 through August 2016, a total of 32 patients with 34 brainstem metastases of NSCLC were consecutively enrolled and treated with the Cyberknife radiosurgery (CKRS) at The Huashan Hospital. The study was limited to patients with NSCLC, which was confirmed by postoperative pathological examination. Patients were treated by CKRS as an initial treatment or a second treatment after whole-brain radiation therapy (WBRT). Quality of life was assessed by the SF-12 score and neurological examination.

RESULTS

Four out of the 32 (12.5%) patients received WBRT before or concurrent with CKRS treatment. The mean survival time after CKRS was 10.0 (95%CI: 6.0-14.0) months. Karnofsky performance score was not the independent predictor of survival after radiosurgery as analyzed by log-rank test (p = 0.392). Age, however, was a significant predictor of improved survival as analyzed by multivariate analysis (p = 0.024). SF-12 physical component scores demonstrated no significant change after treatment.

CONCLUSIONS

The CKSR is a non-invasive, safe, and effective modality in the treatment of patients with brainstem metastases of NSCLC. Better therapeutic outcomes of CKSR for brainstem metastasis might be achieved in the patients older than 65 years old.

Adaptive hypofractionated gamma knife radiosurgery in the acute management of brainstem metastases

Background:

Intrinsic brainstem metastases are life-threatening neoplasms requiring rapid, effective intervention. Microsurgery is considered not feasible in most cases and systemic treatment seldom provides a successful outcome. In this context, radiation therapy remains the best option but adverse radiation effects (ARE) remain a major concern. A dose-adaptive gamma knife procedure coined as Rapid Rescue Radiosurgery (3R) offers the possibility to treat these lesions whilst reducing the risk of ARE evolvement. We report the results of 3R applied to a group of patients with brainstem metastases.

Methods:

Eight patients with nine brainstem metastases, having undergone three separate, dose-adapted gamma knife radiosurgery (GKRS) procedures over 7 days, were retrospectively analyzed in terms of tumor volume reduction, local control rates, and ARE-development under the period of treatment and at least 6 months after treatment completion.

Results:

Mean peripheral doses at GKRS 1, GKRS 2, and GKRS 3 were 7.4, 7.7, and 8.2 Gy (range 6–9 Gy) set at the 35–50% isodose lines. Mean tumor volume reduction between GKRS 1 and GKRS 3 was −15% and −56% at first follow-up. Four patients developed radiologic signs of ARE but remained clinically asymptomatic. One patient developed a local recurrence at 34 months. Mean survival from GKRS 1 was 13 months. Two patients were still alive at the time of paper submission (10 and 23 months from GKRS 1).

Conclusions:

In this study, 3R proved effective in terms of tumor volume reduction, rescue/preservation of neurological function, and limited ARE evolvement.

Toxicity of Radiosurgery for Brainstem Metastases

BACKGROUND

Although stereotactic radiosurgery (SRS) is an effective modality in the treatment of brainstem metastases (BSM), radiation-induced toxicity remains a critical concern. To better understand how severe or life-threatening toxicity is affected by the location of lesions treated in the brainstem, a review of all available studies reporting SRS treatment for BSM was performed.

METHODS

Twenty-nine retrospective studies investigating SRS for BSM were reviewed.

RESULTS

The rates of grade 3 or greater toxicity, based on the Common Terminology Criteria for Adverse Events, varied from 0 to 9.5% (mean 3.4 ± 2.9%). Overall, the median time to toxicity after SRS was 3 months, with 90% of toxicities occurring before 9 months. A total of 1243 cases had toxicity and location data available. Toxicity rates for lesions located in the medulla were 0.8% (1/131), compared with midbrain and pons, respectively, 2.8% (8/288) and 3.0% (24/811).

CONCLUSIONS

Current data suggest that brainstem substructure location does not predict for toxicity and lesion volume within this cohort with median tumor volumes 0.04-2.8 cc does not predict for toxicity.

Brainstem metastases treated with Gamma Knife stereotactic radiosurgery: the Indiana University Health experience

Brainstem metastases offer a unique challenge in cancer treatment, yet stereotactic radiosurgery (SRS) has proven to be an effective modality in treating these tumors. This report discusses the clinical outcomes of patients with brainstem metastases treated at Indiana University with Gamma Knife (GK) radiosurgery from 2008 to 2016. 19 brainstem metastases from 14 patients who had follow-up brain imaging were identified. Median tumor volume was 0.04 cc (range: 0.01–2.0 cc). Median prescribed dose was 17.5 Gy to the 50% isodose line (range: 14–22 Gy). Median survival after GK SRS treatment to brainstem lesion was 17.2 months (range: 2.8–45.6 months). The experience at Indiana University confirms the safety and efficacy of range of GK SRS prescription doses (14–22 Gy) to brainstem metastases.

Radiosurgery for brainstem metastases with and without whole brain radiotherapy: clinical series and literature review

OBJECTIVE

The objective of this study was to investigate outcomes for patients with brainstem metastases treated with stereotactic radiosurgery (SRS).

METHODS

Patients with brainstem metastases treated with SRS between April 2006 and June 2012 were identified from a prospective database. Patient and treatment-related factors were recorded. Kaplan-Meier analysis was used to calculate survival and freedom from local and distant brain progression. Univariate and multivariate Cox regression was used to identify factors important for overall survival.

RESULTS

In total, 44 patients received SRS for 48 brainstem metastases of whom 33 (75 %) also received whole brain radiotherapy (WBRT): 23 patients (52 %) WBRT prior to SRS, 6 (13.6 %) WBRT concurrently with SRS and 4 (9.0 %) WBRT after SRS. Eight patients received a second course of WBRT at further progression. Median target volume was 1.33 cc (range 0.04-12.17) and median prescribed marginal dose was 15 Gy (range 10-22). There were four cases of local failure, and 6-month and 1-year freedom from local failure was 84.6 and 76.9 %, respectively. Median overall survival (OS) was 5.4 months. There were four cases of radionecrosis, 2 (4.8 %) of which were symptomatic. The absence of external beam brain radiotherapy (predominantly WBRT) showed a trend towards improved OS on univariate analysis. Neither local nor distant brain failure significantly impacted OS.

CONCLUSION

This retrospective series of patients treated with SRS for brainstem metastases, largely in combination with at least one course of WBRT, demonstrates that this approach is safe and results in good local control. In this cohort, no variables significantly impacted OS, including intracranial control.

Medullary metastasis of a malignant peripheral nerve sheath tumor: A case report

The present study reports a case of medullary metastasis without lung metastasis that occurred as a result of a malignant peripheral nerve sheath tumor (MPNST). An 81-year-old woman presented with a MPNST in the left brachial plexus, arising from the cervical nerve root. The patient underwent carbon ion radiotherapy; however, tumor recurrence was identified in the left shoulder. Subsequently, the patient underwent wide excision. Three weeks subsequent to surgery, imbalance and dysarthria developed suddenly. Dysphagia emerged and left upper limb pain disappeared on the day after symptom development. Magnetic resonance imaging (MRI) revealed that this was due to metastasis to the medulla. Five days subsequent to the onset of dysarthria, the patient succumbed due to respiratory failure. To the best of our knowledge, no previous cases of medullary metastasis arising from a MPNST in the absence of lung metastasis have been reported. MRI is a useful examination tool for the identification of brain metastases; however, the high cost of MRI as a routine examination must be considered due to the rarity of brain metastases. Therefore, methods to detect brain metastasis warrant further investigation.

Stereotactic Radiosurgery for Brainstem Metastases: An International Cooperative Study to Define Response and Toxicity

PURPOSE

To pool data across multiple institutions internationally and report on the cumulative experience of brainstem stereotactic radiosurgery (SRS).

METHODS AND MATERIALS

Data on patients with brainstem metastases treated with SRS were collected through the International Gamma Knife Research Foundation. Clinical, radiographic, and dosimetric characteristics were compared for factors prognostic for local control (LC) and overall survival (OS) using univariate and multivariate analyses.

RESULTS

Of 547 patients with 596 brainstem metastases treated with SRS, treatment of 7.4% of tumors resulted in severe SRS-induced toxicity (grade ≥3, increased odds with increasing tumor volume, margin dose, and whole-brain irradiation). Local control at 12 months after SRS was 81.8% and was improved with increasing margin dose and maximum dose. Overall survival at 12 months after SRS was 32.7% and impacted by age, gender, number of metastases, tumor histology, and performance score.

CONCLUSIONS

Our study provides additional evidence that SRS has become an option for patients with brainstem metastases, with an excellent benefit-to-risk ratio in the hands of experienced clinicians. Prior whole-brain irradiation increases the risk of severe toxicity in brainstem metastasis patients undergoing SRS.

Adaptive hypofractionated gamma knife radiosurgery for a large brainstem metastasis

Background:

To demonstrate how adaptive hypofractionated radiosurgery by gamma knife (GK) can be successfully utilized to treat a large brainstem metastasis - a novel approach to a challenging clinical situation.

Case Description:

A 42-year-old woman, diagnosed with metastatic nonsmall cell lung cancer in July 2011, initially treated with chemotherapy and tyrosine kinase inhibitors, developed multiple brain metastases March 2013, with subsequent whole brain radiotherapy, after which a magnetic resonance imaging (MRI) showed a significant volume regression of all brain metastases. A follow-up MRI in October 2013 revealed a growing brainstem lesion of 26 mm. Linear accelerator-based radiotherapy and microsurgery were judged contraindicated, why the decision was made to treat the patient with three separate radiosurgical sessions during the course of 1 week, with an 18% tumor volume reduction demonstrated after the last treatment. Follow-up MRI 2.5 months after her radiosurgical treatment showed a tumor volume reduction of 67% compared to the 1^st day of treatment. Later on, the patient developed a radiation-induced perilesional edema although without major clinical implications. An MRI at 12 months and 18-fluoro-deoxyglucose positron emission tomography of the brain at 13 months showed decreased edema with no signs of tumor recurrence. Despite disease progression during the last months of her life, the patient's condition remained overall acceptable.

Conclusion:

GK-based stereotactic adaptive hypofractionation proved to be effective to achieve tumor control while limiting local adverse reactions. This surgical modality should be considered when managing larger brain lesions in critical areas.

CyberKnife radiosurgery for brainstem metastases: Management and outcomes and a review of the literature

To our knowledge this paper is the first to use recursive partitioning analysis (RPA) for brainstem metastasis (BSM) patient outcomes, after CyberKnife radiosurgery (CKRS; Accuray, Sunnyvale, CA, USA); nine similar previous publications used mainly Gamma Knife radiosurgery (Elekta AB, Stockholm, Sweden). Retrospective chart reviews from 2006-2013 of 949 CKRS-treated brain metastasis patients showed 54 BSM patients (5.7%): 35 RPA Class II (65%) and 19 Class III (35%). There were 30 women (56%) and 24 men (44%). The median age was 59 years (range 36-80) and median follow-up was 5 months (range 1-52). Twenty-three patients (43%) had lung carcinoma BSM and 12 (22%) had breast cancer BSM. Fifty-four RPA Class II and III BSM patients had a median overall survival (OS) of 5 months, and for each Class 8 and 2 months, respectively. Of 36 RPA Class II and III patients with available symptoms (n=31) and findings (n=33), improvement/stability occurred in the majority for symptoms (86%) and findings (92%). Of 35 cases, 28 (80%) achieved BSM local control (LC); 13/14 with breast histology (93%) and 10/13 with lung histology (77%). All six RPA Class II and III patients with controlled extracranial systemic disease (ESD) experienced LC. Median tumor volume was 0.14 cm(3); of 34 RPA Class II and III cases, 26 LC patients had a 0,13 cm(3) median tumor volume while it was 0.27 cm(3) in the eight local failures. Of 35 cases, single session equivalent dosages less than the median (n=13), at the 17.9 Gy median (n=5) and greater than the median (n=17) had BSM LC in 10 (77%), four (80%) and 14 cases (82%), respectively. Univariate analysis showed Karnofsky Performance Score, RPA Class and ESD-control predicted OS. CKRS is useful for RPA Class II and III BSM patients with effective clinical and local BSM control.

Brainstem metastases treated with stereotactic radiosurgery: safety, efficacy, and dose response

The safety and efficacy of stereotactic radiosurgery (SRS) in the brainstem is questioned by some over concern of violating historical brainstem SRS dose tolerance. Our purpose was to report on the clinical outcomes of patients treated at our institution with radiosurgery for brainstem metastases. Patients with metastatic tumors within or directly abutting the brainstem from 1992 to 2014 were analyzed. Patient and tumor characteristics, SRS parameters, and toxicity were recorded and analyzed for associations with local control and survival. Multivariate statistical analysis was performed using Cox proportional hazards modeling. One-hundred and eighty-nine (189) brainstem metastases from 161 patients were included in our analysis. Whole brain irradiation was administered prior to SRS in 52 % of patients. The median margin dose was 18 Gy prescribed to the 50 % isodose line. Median imaging follow up was 5.4 months and median survival was 5.5 months after SRS. At last follow up, local control was achieved in 87.3 % of brainstem lesions treated. There were 3 recorded events of grade 3-5 toxicity (1.8 %). On multivariate analysis, a margin dose ≥16 Gy was associated with improved local control (p = 0.049) and greater KPS score was associated with improved overall survival following SRS (p = 0.024). Patients with brainstem metastases who have limited intracranial disease and/or who have received whole brain irradiation should be considered for SRS. Margin doses of at least 16 Gy are associated with superior local control, and serious radiation toxicity in SRS for brainstem metastasis appears rare.

Stereotactic Radiosurgery for Metastases in Eloquent Central Brain Locations

Background: To examine stereotactic radiosurgery (SRS) following whole brain radiotherapy for metastases in eloquent, central brain locations: brainstem, thalamus, and basal ganglia. Methods: We conducted a retrospective review of patients with metastases in eloquent, central brain locations who were treated with SRS between January 2000 and April 2012. All patients had whole brain radiotherapy. Patients eligible for SRS had one to three brain metastases, metastasis size ≤4 cm, and Karnofsky performance status ≥70. Local progression-free survival and overall survival were calculated using the Kaplan-Meier method. Results: For 24 patients, the median age was 50 years (range, 36-73). Metastases by location were: 11 brainstem, 9 thalamus, and 5 basal ganglia. The median metastasis size was 15 mm (range, 2-33) and the median SRS dose prescription was 15 Gy (range, 12-24). The median local progression-free survival was 13.7 months and median overall survival was 16.4 months. Compared with a cohort of 188 patients with noneloquent brain metastases receiving a median dose of 24 Gy, overall survival of 10.8 months was not significantly different (p=0.16). The only symptomatic complication was grade 2 headache in 8.3%. Asymptomatic adverse radiologic events were radionecrosis in two (8.3%), peritumoural edema in four (16.7%), and hemorrhage in one patient (4.2%). Conclusions: Lower SRS marginal doses do not appear to compromise survival in patients with eloquently located brain metastases compared with higher doses for other brain metastases, with minimal symptomatic complications.

Gamma knife stereotactic radiosurgery in the treatment of brainstem metastases: The MD Anderson experience

BACKGROUND

Brainstem metastases (BSMs) represent a significant treatment challenge. Stereotactic radiosurgery (SRS) is often used to treat BSM. We report our experience in the treatment of BSM with Gamma Knife SRS (GK_SRS).

METHODS

The records of 1962 patients with brain metastases treated with GK_SRS between 2009 and 2013 were retrospectively reviewed. Seventy-four patients with 77 BSMs and follow-up brain imaging were identified. Local control (LC), overall survival (OS), progression-free survival (PFS), and toxicity were assessed.

RESULTS

Median follow-up was 5.5 months (range, 0.2-48.5 months). Median tumor volume was 0.13 cm³ (range, 0.003-5.58 cm³). Median treatment dose was 16 Gy (range, 10-20 Gy) prescribed to 50% isodose line (range, 40%-86%). Crude LC was 94% (72/77). Kaplan-Meier estimate of median OS was 8.5 months (95% CI, 5.6-9.4 months). Symptomatic lesions and larger lesions, especially size ≥2 cm³, were associated with worse LC (HR = 8.70, P = .05; HR = 14.55, P = .02; HR = 62.81, P < .001) and worse OS (HR = 2.00, P = .02; HR = 2.14, P = .03; HR = 2.81, P = .008). Thirty-six percent of BSMs were symptomatic, of which 36% (10/28) resolved after SRS and 50% (14/28) had stable or improved symptoms. Actuarial median PFS was 3.9 months (95% CI, 2.7-4.9 months). Midbrain location was significant for worse PFS (HR = 2.29, P = .03). Toxicity was low (8%, 6/74), with size and midbrain location associated with increased toxicity (HR 1.57, P = .05; HR = 5.25, P = .045).

CONCLUSIONS

GK_SRS is associated with high LC (94%) and low toxicity (8%) for BSMs. Presence of symptoms or lesion size ≥ 2 cm³ was predictive of worse LC and OS.

Stereotactic aspiration combined with gamma knife radiosurgery for the treatment of cystic brainstem metastasis originating from lung adenosquamous carcinoma: A case report

Brainstem metastases have a poor prognosis and are difficult to manage. The present study describes the first case of histopathologically-confirmed brainstem metastasis originating from lung adenosquamous carcinoma, and discusses the outcomes of treatment by stereotactic aspiration combined with gamma knife radiosurgery (GKRS). A 59-year-old female presented with a cystic mass (15×12×13 mm; volume, 1.3 cm³) located in the pons, two years following surgical treatment for adenosquamous carcinoma of the lung. The patient received initial GKRS for the lesion in the pons with a total dose of 54.0 Gy, however, the volume of the mass subsequently increased to 3.9 cm³ over a period of three months. Computed tomography-guided stereotactic biopsy and aspiration of the intratumoral cyst were performed, yielding 2.0 cm³ of yellow-white fluid. Histology confirmed the diagnosis of adenosquamous carcinoma. Aspiration provided immediate symptomatic relief, and was followed one week later by repeat GKRS with a dose of 12.0 Gy. The patient survived for 12 months following the repeat GKRS; however, later succumbed to the disease after lapsing into a two-week coma. The findings of this case suggest that stereotactic aspiration of cysts may improve the effects of GKRS for the treatment of cystic brainstem metastasis; the decrease in tumor volume allowed a higher radiation dose to be administered with a lower risk of radiation-induced side effects. Therefore, stereotactic aspiration combined with GKRS may be an effective treatment for brainstem metastasis originating from adenosquamous carcinoma.

Gamma knife treatment of brainstem metastases

The management of brainstem metastases is challenging. Surgical treatment is usually not an option, and chemotherapy is of limited utility. Stereotactic radiosurgery has emerged as a promising palliative treatment modality in these cases. The goal of this study is to assess our single institution experience treating brainstem metastases with Gamma Knife radiosurgery (GKRS). This retrospective chart review studied 41 patients with brainstem metastases treated with GKRS. The most common primary tumors were lung, breast, renal cell carcinoma, and melanoma. Median age at initial treatment was 59 years. Nineteen (46%) of the patients received whole brain radiation therapy (WBRT) prior to or concurrent with GKRS treatment. Thirty (73%) of the patients had a single brainstem metastasis. The average GKRS dose was 17 Gy. Post-GKRS overall survival at six months was 42%, at 12 months was 22%, and at 24 months was 13%. Local tumor control was achieved in 91% of patients, and there was one patient who had a fatal brain hemorrhage after treatment. Karnofsky performance score (KPS) >80 and the absence of prior WBRT were predictors for improved survival on multivariate analysis (HR 0.60 (p = 0.02), and HR 0.28 (p = 0.02), respectively). GKRS was an effective treatment for brainstem metastases, with excellent local tumor control.

Gamma knife radiosurgery treatment for metastatic melanoma of the trigeminal nerve and brainstem: a case report and a review of the literature

Objective and Importance. Brainstem metastases (BSMs) are uncommon but serious complications of some cancers. They cause significant neurological deficit, and options for treatment are limited. Stereotactic radiosurgery (SRS) has been shown to be a safe and effective treatment for BSMs that prolongs survival and can preserve or in some cases improve neurological function. This case illustrates the use of repeated SRS, specifically Gamma Knife radiosurgery (GKRS) for management of a unique brainstem metastasis. Clinical Presentation. This patient presented 5 years after the removal of a lentigo maligna melanoma from her left cheek with left sided facial numbness and paresthesias with no reported facial weakness. Initial MRI revealed a mass on the left trigeminal nerve that appeared to be a trigeminal schwannoma. Intervention. After only limited response to the first GKRS treatment, a biopsy of the tumor revealed it to be metastatic melanoma, not schwannoma. Over the next two years, the patient would receive 3 more GKRS treatments. These procedures were effective in controlling growth in the treated areas, and the patient has maintained a good quality of life. Conclusion. GKRS has proven in this case to be effective in limiting the growth of this metastatic melanoma without acute adverse effects.

A review of the clinical outcomes for patients diagnosed with brainstem metastasis and treated with stereotactic radiosurgery

Only 3%-5% of all brain metastases are located in the brainstem. We present a comprehensive review of the clinical outcomes from modern studies that treated patients with brainstem metastasis using either a Gamma Knife or a linear accelerator-based stereotactic radiosurgery. The median survival time of patients was compared to better understand what clinical or treatment factors are predictive of improved survival. This information can then be utilized to optimize patient care. The data suggests that higher prescribed marginal dose and the associated greater local control of brainstem lesions are associated with longer patient survival. Further research is necessary to better describe the most effective dose for individual brainstem lesions and to tailor optimum therapy to specific patient subgroups.