Stereotactic radiosurgery for the management of brain metastases

Surgery versus stereotactic radiotherapy for people with single or solitary brain metastasis

BACKGROUND

Brain metastases occur when cancer cells spread from their original site to the brain and are a frequent cause of morbidity and death in people with cancer. They occur in 20% to 40% of people during the course of their disease. Brain metastases are also the most frequent type of brain malignancy. Single and solitary brain metastasis is infrequent and choosing the most appropriate treatment is a clinical challenge. Surgery and stereotactic radiotherapy are two options. For surgery, tumour resection is performed using microsurgical techniques, while in stereotactic radiotherapy, external ionising radiation beams are precisely focused on the brain metastasis. Stereotactic radiotherapy may be given as a single dose, also known as single dose radiosurgery, or in a number of fractions, also known as fractionated stereotactic radiotherapy. There is uncertainty regarding which treatment (surgery or stereotactic radiotherapy) is more effective for people with single or solitary brain metastasis.

OBJECTIVES

To assess the effectiveness and safety of surgery versus stereotactic radiotherapy for people with single or solitary brain metastasis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3, March 2018), MEDLINE and Embase up to 25 March 2018 for relevant studies. We also searched trials databases, grey literature and handsearched relevant literature.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing surgery versus stereotactic radiotherapy, either a single fraction (stereotactic radiosurgery) or multiple fractions (fractionated stereotactic radiotherapy) for treatment of single or solitary brain metastasis.

DATA COLLECTION AND ANALYSIS

Two review authors screened all references, evaluated the quality of the included studies using the Cochrane tool for assessing risk of bias, and performed data extraction. The primary outcomes were overall survival and adverse events. Secondary outcomes included progression-free survival and quality of life . We analysed overall survival and progression-free survival as hazard ratios (HRs) with 95% confidence intervals (CIs), and analysed adverse events as risk ratios (RRs). For quality of life we used mean difference (MD).

MAIN RESULTS

Two RCTs including 85 participants met our inclusion criteria. One study included people with single untreated brain metastasis (n = 64), and the other included people with solitary brain metastasis (22 consented to randomisation and 21 were analysed). We identified a third trial reported as completed and pending results this may be included in future updates of this review. The two included studies were prematurely closed due to poor participant accrual. One study compared surgery plus whole brain radiotherapy (WBRT) versus stereotactic radiosurgery alone, and the second study compared surgery plus WBRT versus stereotactic radiosurgery plus WBRT. Meta-analysis was not possible due to clinical heterogeneity between trial interventions. The overall certainty of evidence was low or very low for all outcomes due to high risk of bias and imprecision.We found no difference in overall survival in either of the two comparisons. For the comparison of surgery plus WBRT versus stereotactic radiosurgery alone: HR 0.92, 95% CI 0.48 to 1.77; 64 participants, very low-certainty evidence. We downgraded the certainty of the evidence to very low due to risk of bias and imprecision. For the comparison of surgery plus WBRT versus stereotactic radiosurgery plus WBRT: HR 0.53, 95% CI 0.20 to 1.42; 21 participants, low-certainty evidence. We downgraded the certainty of the evidence to low due to imprecision. Adverse events were reported in both trial groups in the two studies, showing no differences for surgery plus WBRT versus stereotactic radiosurgery alone (RR 0.31, 95% CI 0.07 to 1.44; 64 participants) and for surgery plus WBRT versus stereotactic radiosurgery plus WBRT (RR 0.37, 95% CI 0.05 to 2.98; 21 participants). Most of the adverse events were related to radiation toxicities. We considered the certainty of the evidence from the two comparisons to be very low due to risk of bias and imprecision.There was no difference in progression-free survival in the study comparing surgery plus WBRT versus stereotactic radiosurgery plus WBRT (HR 0.55, 95% CI 0.22 to 1.38; 21 participants, low-certainty evidence). We downgraded the evidence to low certainty due to imprecision. This outcome was not clearly reported for the other comparison. In general, there were no differences in quality of life between the two studies. The study comparing surgery plus WBRT versus stereotactic radiosurgery plus WBRT found no differences after two months using the QLQ-C30 global scale (MD -10.80, 95% CI -44.67 to 23.07; 14 participants, very low-certainty evidence). We downgraded the certainty of evidence to very low due to risk of bias and imprecision.

AUTHORS' CONCLUSIONS

Currently, there is no definitive evidence regarding the effectiveness and safety of surgery versus stereotactic radiotherapy on overall survival, adverse events, progression-free survival and quality of life in people with single or solitary brain metastasis, and benefits must be decided on a case-by-case basis until well powered and designed trials are available. Given the difficulties in participant accrual, an international multicentred approach should be considered for future studies.

Outcomes of Metastatic Brain Lesions Treated with Radioactive Cs-131 Seeds after Surgery: Experience from One Institution

Introduction

Brain metastases are common in patients with advanced systemic cancer and often recur despite treatment with surgical resection and radiotherapy. Whole brain radiation therapy (WBRT) and stereotactic radiosurgery (SRS) have significantly improved local control rates but are limited by complications including neurocognitive deficits and radiation necrosis. These risks can be higher in the re-irradiation setting. Brachytherapy may be an alternative method of additional targeted adjuvant radiotherapy with acceptable rates of toxicity.

Methods

A retrospective chart review of all patients undergoing resection for metastatic brain lesions and permanent low-dose rate Cs-131 brachytherapy was performed for one institution over a 10-year period. All patients had previous radiation therapy already and, after surgery, were followed with imaging every three months. Patient demographics, disease characteristics, intracranial disease, peri- and post-operative complications, and outcomes were recorded. The primary outcome of interest was local tumor recurrence at the site of brachytherapy while secondary outcomes included distant disease progression (within the brain) and complications such as radiation necrosis.

Results

During the study period, nine cases of individual patients met inclusion criteria. The median preoperative lesion diameter was 3 cm (0.8–4.1). The median overall survival after surgery and brachytherapy was 10.3 months, after excluding two patients who were lost to follow-up. Six of nine patients had no local recurrence, while three patients had development or progression of distant lesions. No patients experienced acute or delayed complications.

Conclusion

Cs-131 brachytherapy is a promising alternative method for controlling brain metastases after previous radiation interventions and surgical resection. In this case series, there were no incidences of local tumor recurrence or complications such as radiation necrosis.

Interventions for the treatment of brain radionecrosis after radiotherapy or radiosurgery

BACKGROUND

Brain radionecrosis (tissue death caused by radiation) can occur following high-dose radiotherapy to brain tissue and can have a significant impact on a person's quality of life (QoL) and function. The underlying pathophysiological mechanism remains unclear for this condition, which makes establishing effective treatments challenging.

OBJECTIVES

To assess the effectiveness of interventions used for the treatment of brain radionecrosis in adults over 18 years old.

SEARCH METHODS

In October 2017, we searched the Cochrane Register of Controlled Trials (CENTRAL), MEDLINE, Embase and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) for eligible studies. We also searched unpublished data through Physicians Data Query, www.controlled-trials.com/rct, www.clinicaltrials.gov, and www.cancer.gov/clinicaltrials for ongoing trials and handsearched relevant conference material.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of any intervention directed to treat brain radionecrosis in adults over 18 years old previously treated with radiation therapy to the brain. We anticipated a limited number of RCTs, so we also planned to include all comparative prospective intervention trials and quasi-randomised trials of interventions for brain radionecrosis in adults as long as these studies had a comparison group that reflects the standard of care (i.e. placebo or corticosteroids). Selection bias was likely to be an issue in all the included non-randomised studies therefore results are interpreted with caution.

DATA COLLECTION AND ANALYSIS

Two review authors (CC, PB) independently extracted data from selected studies and completed a 'Risk of bias' assessment. For dichotomous outcomes, the odds ratio (OR) for the outcome of interest was reported. For continuous outcomes, treatment effect was reported as mean difference (MD) between treatment arms with 95% confidence intervals (CIs).

MAIN RESULTS

Two RCTs and one prospective non-randomised study evaluating pharmacological interventions met the inclusion criteria for this review. As each study evaluated a different drug or intervention using different endpoints, a meta-analysis was not possible. There were no trials of non-pharmacological interventions that met the inclusion criteria.A very small randomised, double-blind, placebo-controlled trial of bevacizumab versus placebo reported that 100% (7/7) of participants on bevacizumab had reduction in brain oedema by at least 25% and reduction in post-gadolinium enhancement, whereas all those receiving placebo had clinical or radiological worsening or both. This was an encouraging finding but due to the small sample size we did not report a relative effect. The authors also failed to provide adequate details regarding the randomisation and blinding procedures Therefore, the certainty of this evidence is low and a larger RCT adhering to reporting standards is needed.An open-label RCT demonstrated a greater reduction in brain oedema (T2 hyperintensity) in the edaravone plus corticosteroid group than in the corticosteroid alone group (MD was 3.03 (95% CI 0.14 to 5.92; low-certainty evidence due to high risk of bias and imprecision); although the result approached borderline significance, there was no evidence of any important difference in the reduction in post-gadolinium enhancement between arms (MD = 0.47, 95% CI - 0.80 to 1.74; low-certainty evidence due to high risk of bias and imprecision).In the RCT of bevacizumab versus placebo, all seven participants receiving bevacizumab were reported to have neurological improvement, whereas five of seven participants on placebo had neurological worsening (very low-certainty evidence due to small sample size and concerns over validity of analyses). While no adverse events were noted with placebo, three severe adverse events were noted with bevacizumab, which included aspiration pneumonia, pulmonary embolus and superior sagittal sinus thrombosis. In the RCT of corticosteroids with or without edaravone, the participants who received the combination treatment were noted to have significantly greater clinical improvement than corticosteroids alone based on LENT/SOMA scale (OR = 2.51, 95% CI 1.26 to 5.01; low-certainty evidence due to open-label design). No differences in treatment toxicities were observed between arms.One included prospective non-randomised study of alpha-tocopherol (vitamin E) versus no active treatment was found but it did not include any radiological assessment. As only one included study was a double-blinded randomised controlled trial, the other studies were prone to selection and detection biases.None of the included studies reported quality of life outcomes or adequately reported details about corticosteroid requirements.A limited number of prospective studies were identified but subsequently excluded as these studies had a limited number of participants evaluating different pharmacological interventions using variable endpoints.

AUTHORS' CONCLUSIONS

There is a lack of good certainty evidence to help quantify the risks and benefits of interventions for the treatment of brain radionecrosis after radiotherapy or radiosurgery. In an RCT of 14 patients, bevacizumab showed radiological response which was associated with minimal improvement in cognition or symptom severity. Although it was a randomised trial by design, the small sample size limits the quality of data. A trial of edaravone plus corticosteroids versus corticosteroids alone reported greater reduction in the surrounding oedema with combination treatment but no effect on the enhancing radionecrosis lesion. Due to the open-label design and wide confidence intervals in the results, the quality of this data was also low. There was no evidence to support any non-pharmacological interventions for the treatment of radionecrosis. Further prospective randomised studies of pharmacological and non-pharmacological interventions are needed to generate stronger evidence. Two ongoing RCTs, one evaluating bevacizumab and one evaluating hyperbaric oxygen therapy were identified.

Predictors of quality of life and survival following Gamma Knife surgery for lung cancer brain metastases: a prospective study

OBJECTIVE

Lung cancer (LC) patients who develop brain metastases (BMs) have a poor prognosis. Estimations of survival and risk of treatment-related deterioration in quality of life (QOL) are important when deciding on treatment. Although we know of several prognostic factors for LC patients with BMs, the role of QOL has not been established. Authors of this study set out to evaluate changes in QOL following Gamma Knife surgery (GKS) for BMs in LC patients and QOL as a prognostic factor for survival.

METHODS

Forty-four of 48 consecutive LC patients with BMs underwent GKS in the period from May 2010 to September 2011, and their QOL was prospectively assessed before and 1, 3, 6, 9, and 12 months after GKS by using the Functional Assessment of Cancer Therapy–Brain (FACT-BR) questionnaire. A mixed linear regression model was used to identify potential predictive factors for QOL and to assess the effect of GKS and the disease course on QOL at follow-up.

RESULTS

Mean QOL as measured by the brain cancer subscale (BRCS) of the FACT-BR remained stable from baseline (score 53.0) up to 12 months post-GKS (57.1; p = 0.624). The BRCS score improved for 32 patients (72.3%) with a total BM volume ≤ 5 cm3. Mean improvement in these patients was 0.45 points each month of follow-up, compared to a decline of 0.50 points each month despite GKS treatment in patients with BM volumes > 5 cm3 (p = 0.04). Asymptomatic BMs (p = 0.01), a lower recursive partitioning analysis (RPA) classification (p = 0.04), and a higher Karnofsky Performance Scale (KPS) score (p < 0.01) at baseline were predictors for a high, stable QOL after GKS. After multivariate analysis, a high KPS score (p < 0.01) remained the only positive predictor of a high, stable QOL post-GKS.

Median survival post-GKS was 5.6 months (95% CI 1.0–10.3). A higher BRCS score (p = 0.01), higher KPS score (p = 0.01), female sex (p = 0.01), and the absence of liver (p = 0.02), adrenal (p = 0.02), and bone metastases (p = 0.03) predicted longer survival in unadjusted models. However, in multivariate analyses, a higher BRCS score (p < 0.01), female sex (p = 0.01), and the absence of bone metastases (p = 0.02) at GKS remained significant predictors. Finally, the BRCS score’s predictive value for survival was compared with the values for the variables behind well-known prognostic indices: age, KPS score, extracranial disease status, and number and volume of BMs. Both BRCS score (p = 0.01) and BM volume (p = 0.05) remained significant predictors for survival in the final model.

CONCLUSIONS

Patient-reported QOL according to the BRCS is a predictor of survival in patients with BMs and may be helpful in deciding on the optimal treatment. Gamma Knife surgery is a safe and effective therapeutic modality that improves QOL for LC patients with a BM volume ≤ 5 cm3 at treatment. Careful follow-up and salvage therapy on demand seem to prevent worsening of QOL due to relapse of BMs.

A randomised trial to compare cognitive outcome after gamma knife radiosurgery versus whole brain radiation therapy in patients with multiple brain metastases: research protocol CAR-study B

BACKGROUND

Gamma Knife radiosurgery (GKRS) is increasingly applied in patients with multiple brain metastases and is expected to have less adverse effects in cognitive functioning than whole brain radiation therapy (WBRT). Effective treatment with the least negative cognitive side effects is increasingly becoming important, as more patients with brain metastases live longer due to more and better systemic treatment options. There are no published randomized trials yet directly comparing GKRS to WBRT in patients with multiple brain metastases that include objective neuropsychological testing.

METHODS

CAR-Study B is a prospective randomised trial comparing cognitive outcome after GKRS or WBRT in adult patients with 11-20 newly diagnosed brain metastases on a contrast-enhanced MRI-scan, KPS ≥70 and life expectancy of at least 3 months. Randomisation by the method of minimization, is stratified by the cumulative tumour volume in the brain, systemic treatment, KPS, histology, baseline cognitive functioning and age. The primary endpoint is the between-group difference in the percentage of patients with significant memory decline at 3 months. Secondary endpoints include overall survival, local control, development of new brain metastases, cognitive functioning over time, quality of life, depression, anxiety and fatigue. Cognitive functioning is assessed by a standardised neuropsychological test battery. Assessments (cognitive testing, questionnaires and MRI-scans) are scheduled at baseline and at 3, 6, 9, 12 and 15 months after treatment.

DISCUSSION

Knowledge gained from this trial may be used to inform individual patients with BM more precisely about the cognitive effects they can expect from treatment, and to assist both doctors and patients in making (shared) individual treatment decisions. This trial is currently recruiting. Target accrual: 23 patients at 3-months follow-up in both groups.

TRIAL REGISTRATION

The Netherlands Trials Register number NTR5463. ClinicalTrials.gov registration number NCT02953717 , first received October 27, 2016, 8 patients were enrolled in this study on 31 July 2017.

Impact of pemetrexed on intracranial disease control and radiation necrosis in patients with brain metastases from non-small cell lung cancer receiving stereotactic radiation

BACKGROUND

Pemetrexed is a folate antimetabolite used in the management of advanced adenocarcinoma of the lung. We sought to assess the impact of pemetrexed on intracranial disease control and radiation-related toxicity among patients with adenocarcinoma of the lung who received stereotactic radiation for brain metastases.

MATERIALS/METHODS

We identified 149 patients with adenocarcinoma of the lung and newly diagnosed brain metastases without a targetable mutation receiving stereotactic radiation. Kaplan-Meier plots and Cox regression were employed to assess whether use of pemetrexed was associated with intracranial disease control and radiation necrosis.

RESULTS

Among the entire cohort, 105 patients received pemetrexed while 44 did not. Among patients who were chemotherapy-naïve, use of pemetrexed (n = 43) versus alternative regimens after stereotactic radiation (n = 24) was associated with a reduced likelihood of developing new brain metastases (HR 0.42, 95% CI 0.22-0.79, p = 0.006) and a reduced need for salvage brain-directed radiation therapy (HR 0.36, 95% CI 0.18-0.73, p = 0.005). Pemetrexed use was associated with increased radiographic necrosis. (HR 2.70, 95% CI 1.09-6.70, p = 0.03).

CONCLUSIONS

Patients receiving pemetrexed after brain-directed stereotactic radiation appear to benefit from improved intracranial disease control at the possible expense of radiation-related radiographic necrosis. Whether symptomatic radiation injury occurs more frequently in patients receiving pemetrexed requires further study.

Three or More Courses of Stereotactic Radiosurgery for Patients with Multiply Recurrent Brain Metastases

BACKGROUND

Although patients with brain metastasis are treated with primary stereotactic radiosurgery (SRS), the use of salvage therapies and their consequence remains understudied.

OBJECTIVE

To study the intracranial recurrence patterns and salvage therapies for patients who underwent multiple SRS courses.

METHODS

A retrospective review was performed of 59 patients with brain metastases who underwent ≥3 SRS courses for new lesions. Cox regression analyzed factors predictive for overall survival.

RESULTS

The median age at diagnosis was 52 years. Over time, patients underwent a median of 3 courses of SRS (range: 3-8) to a total of 765 different brain metastases. The 6-month risk of distant intracranial recurrence after the first SRS treatment was 64% (95% confidence interval: 52%-77%). Overall survival was 40% (95% confidence interval: 28%-53%) at 24 months. Only 24 patients (41%) had a decline in their Karnofsky Performance Status ≤70 at last office visit. Quality of life was preserved among 77% of patients at 12 months, with 45% experiencing clinically significant improvement during clinical follow-up. Radiation necrosis developed in 10 patients (17%). On multivariate analysis, gender (males, Hazard Ratio [HR]: 2.0, P < .05), Karnofsky Performance Status ≤80 (HR 3.2, P < .001), extracranial metastases (HR: 3.6, P < .001), and a distant intracranial recurrence ≤3 months from initial to repeat SRS (HR: 3.8, P < .001) were associated with a poorer survival.

CONCLUSION

In selected patients, performing ≥3 SRS courses controls intracranial disease. Patients may need salvage SRS for distant intracranial relapse, but focal retreatments are associated with modest toxicity, do not appear to negatively affect a patient's performance status, and help preserve quality of life.

Neurocognitive aspects of brain metastasis

Brain metastases are common, occurring in approximately 20% of cancer patients. One of the biggest concerns for these patients and their families is neurocognitive decline. Neurocognitive issues in this patient population are complex and many patients have neurocognitive impairment due to systemic therapies even before they develop brain metastases. The development of brain metastases as well as the treatment of these tumors can cause decline in neurocognitive function. Diffuse treatments such as whole-brain radiotherapy are more frequently associated with neurocognitive decline than focal interventions such as radiosurgery, surgical resection, and implantable chemotherapy wafers. For patients with brain metastases treatment decisions require a multidisciplinary approach, balancing many factors including the neurocognitive impact of treatment and the disease process itself. Finally, to continue to advance the field there needs to be continued utilization, both off and on clinical trial, of performance-based clinical outcome assessments (i.e., neurocognitive tests) to objectively assess and measure the neurocognitive outcomes of these patients.

Local control and overall survival for adjuvant stereotactic radiosurgery in patients with residual or recurrent disease

Prior studies of post-operative stereotactic radiosurgery (SRS) have not distinguished between Adjuvant SRS (ARS) versus Adjuvant SRS to residual/recurrent disease (ARD). In this study, we defined ARS and ARD and investigated local control (LC), overall survival (OS), distant development of brain metastases (DBF), and leptomeningeal disease (LMD). We retrospectively identified BM patients who received surgical resection and SRS for BM from an IRB approved database between Jan 2009-Aug 2015. Patients were stratified into two groups: ARS and ARD. LC was determined by follow-up MRI studies and OS was measured from the date of surgery. LC and OS were assessed using the Kaplan-Meier method. 70 cavities underwent surgical resection of BM and received SRS to the post-operative bed. 41 cavities were classified as ARS and 29 as ARD. There was no significant difference in 12-month LC between the ARS and ARD group (71.4 vs. 80.8%, respectively; p = 0.135) from the time point of SRS. The overall 1-year survival for ARS and ARD was 79.9 and 86.1%, respectively (p = 0.339). Mean time to progression was 6.45 and 8.0 months and median follow-up was 10 and 15 months for ARS and ARD, respectively. 11.8% of ARS patients and 15.4% of ARD patients developed LMD, p = 0.72. 29.4% of ARS and 48.0% of ARD patients developed DBF, p = 0.145. Our findings suggest that observation after surgical resection, with subsequent treatment with SRS after the development of local failure, may not compromise treatment efficacy. If validated, this would spare patients who do not recur post-surgically from additional treatment.

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.

Lung cancer-associated brain metastasis: Molecular mechanisms and therapeutic options

BACKGROUND

Lung cancer is the most common cause of cancer-related mortality in humans. There are several reasons for this high rate of mortality, including metastasis to several organs, especially the brain. In fact, lung cancer is responsible for approximately 50% of all brain metastases, which are very difficult to manage. Understanding the cellular and molecular mechanisms underlying lung cancer-associated brain metastasis brings up novel therapeutic promises with the hope to ameliorate the severity of the disease. Here, we provide an overview of the molecular mechanisms underlying the pathogenesis of lung cancer dissemination and metastasis to the brain, as well as promising horizons for impeding lung cancer brain metastasis, including the role of cancer stem cells, the blood-brain barrier, interactions of lung cancer cells with the brain microenvironment and lung cancer-driven systemic processes, as well as the role of growth factor/receptor tyrosine kinases, cell adhesion molecules and non-coding RNAs. In addition, we provide an overview of current and novel therapeutic approaches, including radiotherapy, surgery and stereotactic radiosurgery, chemotherapy, as also targeted cancer stem cell and epithelial-mesenchymal transition (EMT)-based therapies, micro-RNA-based therapies and other small molecule or antibody-based therapies. We will also discuss the daunting potential of some combined therapies.

CONCLUSIONS

The identification of molecular mechanisms underlying lung cancer metastasis has opened up new avenues towards their eradication and provides interesting opportunities for future research aimed at the development of novel targeted therapies.

Dynamic O-(2-18F-fluoroethyl)-L-tyrosine positron emission tomography differentiates brain metastasis recurrence from radiation injury after radiotherapy

Background

The aim of this study was to investigate the potential of dynamic O-(2-[18F]fluoroethyl)-L-tyrosine (18F-FET) PET for differentiating local recurrent brain metastasis from radiation injury after radiotherapy since contrast-enhanced MRI often remains inconclusive.

Methods

Sixty-two patients (mean age, 55 ± 11 y) with single or multiple contrast-enhancing brain lesions (n = 76) on MRI after radiotherapy of brain metastases (predominantly stereotactic radiosurgery) were investigated with dynamic 18F-FET PET. Maximum and mean tumor-to-brain ratios (TBRmax, TBRmean) of 18F-FET uptake were determined (20-40 min postinjection) as well as tracer uptake kinetics (ie, time-to-peak and slope of time-activity curves). Diagnoses were confirmed histologically (34%; 26 lesions in 25 patients) or by clinical follow-up (66%; 50 lesions in 37 patients). Diagnostic accuracies of PET parameters for the correct identification of recurrent brain metastasis were evaluated by receiver-operating-characteristic analyses or the chi-square test.

Results

TBRs were significantly higher in recurrent metastases (n = 36) than in radiation injuries (n = 40) (TBRmax 3.3 ± 1.0 vs 2.2 ± 0.4, P < .001; TBRmean 2.2 ± 0.4 vs 1.7 ± 0.3, P < .001). The highest accuracy (88%) for diagnosing local recurrent metastasis could be obtained with TBRs in combination with the slope of time-activity curves (P < .001).

Conclusions

The results of this study confirm previous preliminary observations that the combined evaluation of the TBRs of 18F-FET uptake and the slope of time-activity curves can differentiate local brain metastasis recurrence from radiation-induced changes with high accuracy. 18F-FET PET may thus contribute significantly to the management of patients with brain metastases.

Optimization of diagnostic performance for differentiation of recurrence from radiation necrosis in patients with metastatic brain tumors using tumor volume-corrected 11C-methionine uptake

Background

Tumor to normal tissue ratio (T/N ratio) on ¹¹C-methionine (¹¹C-MET) positron emission tomography/computed tomography (PET/CT) is affected by variable factors. We investigated whether T/N ratio cutoff values corrected according to metabolic tumor volume (MTV) could improve the diagnostic performance of ¹¹C-MET PET/CT for diagnosis of recurrence in patients with metastatic brain tumor.

Forty-eight patients with metastatic brain tumors underwent ¹¹C-MET PET/CT for differential diagnosis between recurrence and radiation necrosis after gamma knife radiosurgery (GKR). Both T/N ratio and MTV were estimated in each lesion on ¹¹C-MET PET/CT. The lesions were classified into three groups based on MTV criteria (≤ 0.5 cm³; > 0.5, ≤ 4.0 cm³; and > 4.0 cm³). The optimal cutoff values of the T/N ratio from receiver operating characteristic (ROC) curve were determined in each group (MTV-corrected) as well as total lesions (non-corrected). Finally, diagnostic performance of ¹¹C-MET PET/CT was compared with the MTV-corrected cutoff values.

Results

Among 77 lesions, 51 were diagnosed with recurrence. The mean T/N ratio was 2.25 (± 1.12) for recurrent lesions and 1.44 (± 0.22) for radiation necrosis (P < 0.001). T/N ratio of 1.61 (non-corrected) provided the best sensitivity, specificity, and diagnostic accuracy (70.6, 80.8, and 74.0%, respectively). Using the MTV criteria, optimal cutoff values of the T/N ratios in each group were 1.23 (MTV ≤ 0.5 cm³), 1.54 (0.5 cm³ < MTV ≤ 4.0 cm³), and 1.85 (MTV > 4.0 cm³). In small-sized lesions (MTV ≤ 0.5 cm³), MTV-corrected cutoff values (1.23) could maintain favorable diagnostic performance with sensitivity, specificity, and diagnostic accuracy (70.0, 80.0, and 73.3%, respectively), compared to non-corrected cutoff values.

Conclusions

MTV-corrected cutoff values of T/N ratio could maintain the diagnostic performance of ¹¹C-MET PET/CT in small sized, metastatic brain tumors. We expect our results to contribute to reproducible and standardized interpretation of ¹¹C-MET PET/CT.

Dynamic contrast-enhanced MRI perfusion for differentiating between melanoma and lung cancer brain metastases

Brain metastases originating from different primary sites overlap in appearance and are difficult to differentiate with conventional MRI. Dynamic contrast-enhanced (DCE)-MRI can assess tumor microvasculature and has demonstrated utility in characterizing primary brain tumors. Our aim was to evaluate the performance of plasma volume (Vp) and volume transfer coefficient (Ktrans ) derived from DCE-MRI in distinguishing between melanoma and nonsmall cell lung cancer (NSCLC) brain metastases. Forty-seven NSCLC and 23 melanoma brain metastases were retrospectively assessed with DCE-MRI. Regions of interest were manually drawn around the metastases to calculate Vpmean and Kmeantrans. The Mann-Whitney U test and receiver operating characteristic analysis (ROC) were performed to compare perfusion parameters between the two groups. The Vpmean of melanoma brain metastases (4.35, standard deviation [SD] = 1.31) was significantly higher (P = 0.03) than Vpmean of NSCLC brain metastases (2.27, SD = 0.96). The Kmeantrans values were higher in melanoma brain metastases, but the difference between the two groups was not significant (P = 0.12). Based on ROC analysis, a cut-off value of 3.02 for Vpmean (area under curve = 0.659 with SD = 0.074) distinguished between melanoma brain metastases and NSCLC brain metastases (P < 0.01) with 72% specificity. Our data show the DCE-MRI parameter Vpmean can differentiate between melanoma and NSCLC brain metastases. The ability to noninvasively predict tumor histology of brain metastases in patients with multiple malignancies can have important clinical implications.

A prospective patient-focused evaluation of the tolerance and acceptability of a stereotactic radiosurgery procedure

Stereotactic radiosurgery (SRS) is a frequently used non-surgical procedure to treat benign and malignant brain lesions. Few studies have focused on patient perceptions of SRS. The aims of this patient-focused study were to assess patient experiences of SRS, and changes in patient-reported symptoms over 12weeks post-SRS. Using the 6-point Likert Scoring Scale in a diary-format for a less discriminatory evaluation, patients self-reported presence or absence, and severity of physical and psychological symptoms within 24h, 1-week, and 12-weeks post-SRS. Non-parametric repeated measures ANOVA was used to evaluate changes in symptoms. Of the 748 recruited patients, 690 returned the first diary (92%), while 564 patients returned all three diaries for matched responses analysis (82%). Three-quarters of 690 patients reported receiving clear verbal explanations and printed material prior to their procedure, and 99% reported the clinical team were 'very supportive' or gave 'wonderful care'. Fatigue (82%) and headaches (65%) were the most frequently reported symptoms within 24-h post-SRS. Over 12weeks, patients reported significant reductions in headache, nausea, fatigue, anxiety and tension (p<0.001); loss of balance and concentration significantly increased by 12-weeks post-SRS (p<0.001). Some patients attributed symptoms such as fatigue or headaches to the demands of the procedure day. Findings of this study reflect the need to further research patients' physical and psychological symptoms post-SRS, which may differ from the clinicians' perception of the effects of treatment.

Quality of Life following Stereotactic Radiosurgery for Single and Multiple Brain Metastases

BACKGROUND: Given the neurological morbidity and poor prognosis associated with brain metastases, it is critical to deliver appropriate therapy while remaining mindful of patient quality of life (QOL). For many patients, stereotactic radiosurgery (SRS) effectively controls intracranial disease, but QOL outcomes have not been characterized.

OBJECTIVE: To determine the effect of number of brain metastases upon QOL preservation following SRS.

METHODS: The EuroQol 5 Dimensions questionnaire (EQ-5D) and Patient Health Questionnaire 9 instruments were prospectively collected from a cohort of patients undergoing SRS for brain metastasis between 2008 and 2015. These instruments served as measures of overall QOL and depression. QOL deterioration exceeding the minimum clinically important difference was considered failure. Freedom from 12-month EQ-5D index failure was the primary outcome.

RESULTS: One hundred and twenty-two SRS treatments (67 patients, 421 lesions) were eligible for inclusion. Intracranial failure (local or distant) occurred following 61% of treatments. Among 421 lesions, 8% progressed locally. Median follow-up was 12 months.

All subscores of the EQ-5D instrument expectantly worsened at last follow-up; however, the magnitude of this difference (0.079) did not exceed the EQ-5D index minimum clinically important difference (mean 0.752 vs 0.673, P &lt; .01). Twelve-month EQ-5D index QOL preservation was 79%. Patients with more than 3 brain metastases had a greater rate of EQ-5D index deterioration (hazard ratio 4.14, P &lt; .01) than those with a single metastasis.

CONCLUSIONS: Among patients with brain metastasis, QOL preservation must remain paramount as multimodality therapy continues to improve. In the present investigation, 12-month QOL preservation was 79%. However, patients with more than 3 brain metastases were at significantly greater risk for QOL decline.

Significant tumor shift in patients treated with stereotactic radiosurgery for brain metastasis

Introduction

Linac-based stereotactic radiosurgery (SRS) for brain metastases may be influenced by the time interval between treatment preparation and delivery, related to risk of anatomical changes. We studied tumor position shifts and its relations to peritumoral volume edema changes over time, as seen on MRI.

Methods

Twenty-six patients who underwent SRS for brain metastases in our institution were included. We evaluated the occurrence of a tumor shift between the diagnostic MRI and radiotherapy planning MRI. For 42 brain metastases the tumor and peritumoral edema were delineated on the contrast enhanced T1weighted and FLAIR images of both the diagnostic MRI and planning MRI examinations. Centre of Mass (CoM) shifts and tumor borders were evaluated. We evaluated the influence of steroids on peritumoral edema and tumor volume and the correlation with CoM and tumor border changes.

Results

The median values of the CoM shifts and of the maximum distances between the tumor borders obtained from the diagnostic MRI and radiotherapy planning MRI were 1.3 mm (maximum shift of 5.0 mm) and 1.9 mm (maximum distance of 7.4 mm), respectively. We found significant correlations between the absolute change in edema volume and the tumor shift of the CoM (p < 0.001) and tumor border (p = 0.040). Patients who received steroids did not only had a decrease in peritumoral edema, but also had a median decrease in tumor volume of 0.02 cc while patients who did not receive steroids had a median increase of 0.06 cc in tumor volume (p = 0.035).

Conclusion

Our results show that large tumor shifts of brain metastases can occur over time. Because shifts may have a significant impact on the local dose coverage, we recommend minimizing the time between treatment preparation and delivery for Linac based SRS.

Clinical efficacy and safety of surface imaging guided radiosurgery (SIG-RS) in the treatment of benign skull base tumors

Frameless, surface imaging guided radiosurgery (SIG-RS) is a novel platform for stereotactic radiosurgery (SRS) wherein patient positioning is monitored in real-time through infra-red camera tracking of facial topography. Here we describe our initial clinical experience with SIG-RS for the treatment of benign neoplasms of the skull base. We identified 48 patients with benign skull base tumors consecutively treated with SIG-RS at a single institution between 2009 and 2011. Patients were diagnosed with meningioma (n = 22), vestibular schwannoma (n = 20), or nonfunctional pituitary adenoma (n = 6). Local control and treatment-related toxicity were retrospectively assessed. Median follow-up was 65 months (range 61-72 months). Prescription doses were 12-13 Gy in a single fraction (n = 18), 8 Gy × 3 fractions (n = 6), and 5 Gy × 5 fractions (n = 24). Actuarial tumor control rate at 5 years was 98%. No grade ≥3 treatment-related toxicity was observed. Grade ≤2 toxicity was associated with symptomatic lesions (p = 0.049) and single fraction treatment (p = 0.005). SIG-RS for benign skull base tumors produces clinical outcomes comparable to conventional frame-based SRS techniques while enhancing patient comfort.

The impact of tumor biology on survival and response to radiation therapy among patients with non-small cell lung cancer brain metastases

PURPOSE

To investigate the natural history and response to radiation therapy among ALK-rearranged, EGFR-mutated, wild-type adenocarcinoma, and squamous cell non-small cell lung cancer (NSCLC) brain metastases.

METHODS AND MATERIALS

Patients with NSCLC brain metastasis diagnosed from 1989 through 2014 at a single tertiary-care institution were included. The primary outcome was overall survival, whereas secondary outcomes included local failure, distant intracranial failure, and radiation necrosis. Cox proportional hazards regression was used to model overall survival; multivariate competing risks regression was used to model secondary outcomes.

RESULTS

Within the study period, 1920 patients presented with 6312 brain metastases. Squamous histology was associated with poorer median survival compared with adenocarcinomas (5.4 vs 8.8 months, P < .01). Median survival was greatest among ALK+ patients (49.2 months), followed by EGFR+ (20.3 months), and wild-type adenocarcinomas (10.0 months, P < .01). Treatment with estimated glomerular filtration rate inhibitors (hazard ratio [HR], 0.66; P < .01) and vascular endothelial growth factor antibodies (HR, 0.65; P < .01) increased survival independent of mutational status. Among 2056 lesions treated with stereotactic radiosurgery, the 12-month cumulative incidence of local failure was significantly greater among squamous cell carcinomas relative to adenocarcinomas (15% vs 10%, HR, 1.26; P = .04). Patients with ALK+ metastases experienced higher rates of local failure (10%; HR, 2.00; P = .05), distant failure (39%; HR, 2.94; P < .01), and radiation necrosis (18%; HR, 5.77; P < .01), whereas EGFR+ patients experienced the lowest rates of local failure (5%; HR, 0.46; P = .04) and distant failure (3%; HR, 0.13; P = .04).

CONCLUSIONS

Advances in precision medicine have increased survival among select patients with NSCLC. In the present investigation, ALK+ and EGFR+ status were associated with improved survival. However, patients with ALK+ metastases have poor intracranial control relative to EGFR+ metastases, possibly because of limited intracranial penetration of crizotinib compared with estimated glomerular filtration rate inhibitors. Future investigations are warranted to determine the optimal management of ALK+ brain metastases with the introduction of second-generation ALK inhibitors.

Value of serial magnetic resonance imaging in the assessment of brain metastases volume control during stereotactic radiosurgery

AIM

To evaluate brain metastases volume control capabilities of stereotactic radiosurgery (SRS) through serial magnetic resonance (MR) imaging follow-up.

METHODS

MR examinations of 54 brain metastases in 31 patients before and after SRS were reviewed. Patients were included in this study if they had a pre-treatment MR examination and serial follow-up MR examinations at 6 wk, 9 wk, 12 wk, and 12 mo after SRS. The metastasis volume change was categorized at each follow-up as increased (> 20% of the initial volume), stable (± 20% of the initial volume) or decreased (< 20% of the initial volume).

RESULTS

A local tumor control with a significant (P < 0.05) volume decrease was observed in 25 metastases at 6-wk follow-up. Not significant volume change was observed in 23 metastases and a significant volume increase was observed in 6 metastases. At 9-wk follow-up, 15 out of 25 metastases that decreased in size at 6 wk had a transient tumor volume increase, followed by tumor regression at 12 wk. At 12-wk follow-up there was a significant reduction in volume in 45 metastases, and a significant volume increase in 4 metastases. At 12-mo follow-up, 19 metastases increased significantly in size (up to 41% of the initial volume). Volume tumor reduction was correlated to histopathologic subtype.

CONCLUSION

SRS provided an effective local brain metastases volume control that was demonstrated at follow-up MR imaging.

The evolving clinical management of cerebral metastases

Concepts in the management of brain metastases are evolving. Until recently, brain metastases have been considered as a homogenous condition, managed with whole brain radiotherapy, surgical resection for large lesions and stereotactic radiosurgery for smaller lesions. Increasingly, specific systemic medical therapies are being used to treat brain metastases based on the primary site of disease. This disease specific management is causing a change in perspective about brain metastases and has led to improved survival for patients with primary disease subtypes amenable to tailored medical therapies. We review the recent literature to present evidence for the use of subtype specific medical therapies, advances in surgical resection techniques and stereotactic radiosurgery as the primary treatment modalities. The decline in use of whole brain radiotherapy as first line treatment is also discussed. Based on the recent literature, we propose a new management algorithm to reflect the progress in available options for tailoring disease specific treatments and support the change in paradigm to consider brain metastases as separate disease states based on the primary site of cancer rather than as a homogenous entity.

Hypofractionated Stereotactic Radiosurgery and Radiotherapy to Large Resection Cavity of Metastatic Brain Tumors

OBJECTIVE

To evaluate the efficacy of postoperative fractionated stereotactic radiosurgery (FSRS) and hypofractionated stereotactic radiotherapy (SRT) to large surgical cavities after gross total resection of brain metastases.

METHODS

A retrospective analysis of 41 patients who had received tumor-bed FSRS (5 fractions) or SRT (10 fractions) after resection of brain metastasis between 2005 and 2015 was performed. All resection cavities were treated with a frameless linear accelerator-based system. Patients who underwent subtotal resection, single-dose SRS to the resection cavity, or were treated with a fractionation schedule other than 5 or 10 fractions, were excluded.

RESULTS

Twenty-six patients were treated with 5 fractions and 15 patients with 10 fractions. The median planning target volume was 19.78 cm³ (12.3-28 cm³) to the 5-fraction group and 29.79 cm³ (26.3-47.6 cm³) to the 10-fraction group (P = 0.020). The 1-year and 2-year local control rates for all patients were 89.4% and 77.1%, respectively, and 89.6% and 78.6% were free from distant intracranial progression, respectively. No difference was observed in local control or freedom from distant intracranial progression between the 5-fraction or 10-fraction groups. The median overall survival was 28.27 months (95% confidence interval, 19.42-37.12) for all patients. No patient developed necrosis at the resection cavity.

CONCLUSIONS

Fractionation offers the potential to exploit the different biological responses between neoplastic and normal tissues to ionizing radiation. The use of 5 daily doses of 5-6 Gy or 10 daily doses of 3 Gy is a good strategy to have a reasonable local control and avoid neurotoxicity.

Veliparib in combination with whole-brain radiation therapy for patients with brain metastases from non-small cell lung cancer: results of a randomized, global, placebo-controlled study

Veliparib is a potent, orally bioavailable, poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitor that crosses the blood-brain barrier and has been shown to potentiate the effects of radiation in preclinical and early clinical studies. This phase 2, randomized, global study evaluated the efficacy and safety of veliparib in combination with whole-brain radiation therapy (WBRT) in patients with brain metastases from non-small cell lung cancer (NSCLC). Three-hundred and seven patients with brain metastases from NSCLC were randomized 1:1:1 to WBRT (30 Gy in 10 fractions) plus 50 mg veliparib twice daily (BID; n = 103), 200 mg veliparib BID (n = 102), or placebo BID (n = 102). Treatment began within 28 days of diagnosis. Tumor response and safety were assessed; the primary endpoint was overall survival (OS). Patients who received ≥1 dose of treatment were included in the safety analysis. All randomized patients were included in the efficacy endpoint analyses. Patient characteristics were well balanced between treatment arms. Median OS was 185 days for patients treated with WBRT plus placebo and 209 days for WBRT plus veliparib (50 or 200 mg). No statistically significant differences in OS, intracranial response rate, and time to clinical or radiographic progression between any of the treatment arms were noted. No differences were observed in adverse events (all grades) across treatment arms; nausea, fatigue, alopecia, and headache were the most commonly reported. No new safety signals were identified for veliparib. A significant unmet need for therapies that improve the outcomes of patients with brain metastases from NSCLC remains.

Dosimetric comparison between cone/Iris-based and InCise MLC-based CyberKnife plans for single and multiple brain metastases

We performed an evaluation of the CyberKnife InCise MLC by comparing plan qualities for single and multiple brain lesions generated using the first version of InCise MLC, fixed cone, and Iris collimators. We also investigated differences in delivery efficiency among the three collimators. Twenty‐four patients with single or multiple brain mets treated previously in our clinic on a CyberKnife M6 using cone/Iris collimators were selected for this study. Treatment plans were generated for all lesions using the InCise MLC. Number of monitor units, delivery time, target coverage, conformity index, and dose falloff were compared between MLC‐ and clinical cone/Iris‐based plans. Statistical analysis was performed using the nonparametric Wilcoxon‐Mann‐Whitney signed‐rank test. The planning accuracy of the MLC‐based plans was validated using chamber and film measurements. The InCise MLC‐based plans achieved mean dose and target coverage comparable to the cone/Iris‐based plans. Although the conformity indices of the MLC‐based plans were slightly higher than those of the cone/Iris‐based plans, beam delivery time for the MLC‐based plans was shorter by 30%∼40%. For smaller targets or cases with OARs located close to or abutting target volumes, MLC‐based plans provided inferior dose conformity compared to cone/Iris‐based plans. The QA results of MLC‐based plans were within 5% absolute dose difference with over 90% gamma passing rate using 2%/2 mm gamma criteria. The first version of InCise MLC could be a useful delivery modality, especially for clinical situations for which delivery time is a limiting factor or for multitarget cases.

PACS number(s): 87.53.Ly, 87.55.D‐

Management of Brain Metastasis in Patients With Pulmonary Neuroendocrine Carcinomas

Background:

The patterns of intracranial failure in patients with brain metastasis from pulmonary neuroendocrine carcinoma (PNEC) remain unknown.

Methods:

From 1998 to 2013, 29 patients with the diagnosis of PNEC were treated for brain metastasis: 16 patients (55%) underwent whole-brain radiation therapy (WBRT), 5 (17%) patients underwent WBRT with a stereotactic radiosurgery (SRS) boost, and 8 (28%) patients underwent primary SRS alone.

Results:

The median age at treatment was 61 years (range: 44-84 years) and the median follow-up was 9.6 months (0-157.4 months). Of the patients treated with SRS alone, 1 patient had radiographic local progression of disease and 1 patient had a distant intracranial failure. Of the patients treated with WBRT with or without an SRS boost, 9 patients developed intracranial progression, including 1 local failure. No differences in rates of intracranial progression or local failure between the 2 groups ( P = .94 and P = .44, respectively) were observed. The actuarial rates of distant intracranial failure at 12 months were 32.9% (95% confidence interval [95% CI] 8.9%-56.8%) and 25% (95% CI 0.0%-67.4%) in patients undergoing primary WBRT or SRS, respectively ( P = .31). The median overall survival was 15.8 months in patients treated with WBRT and 20.4 months in patients treated with primary SRS ( P = .78).

Conclusion:

Patients with brain metastasis from PNECs can be effectively treated with either WBRT or SRS alone, with a pattern of failure more consistent with non-small cell lung cancer than small cell lung cancer. In this series, there was not a statistically significant increased risk of distant intracranial failure when patients were treated with primary SRS.

Strategies to Alleviate Anxiety Before the Placement of a Stereotactic Radiosurgery Frame

BACKGROUND

Patients scheduled for stereotactic radiosurgery (SRS) need the placement of a head frame for accurate treatment of brain metastases and other abnormalities in the brain. These patients frequently experience anxiety before frame placement. Although there is evidence that preprocedure education can alleviate anxiety, less is known about education for patients undergoing head frame placement.

OBJECTIVE

The aim of this study was to determine whether a preprocedure educational intervention can reduce/alleviate anxiety for patients undergoing head frame placement for SRS.

METHODS

This study was a practice improvement project using a nonrandomized controlled design to evaluate patients (N = 28) diagnosed with metastasized brain cancer or other abnormalities in the brain. Patients aged ≥19 and <75 years were recruited, and all participants had been radiographically diagnosed and were dispositioned for SRS. The control group (n = 14) received the standard preprocedure teaching, and the intervention group (n = 14) received both the standard preprocedure teaching and an additional educational intervention. Data collecting tools included the Hospital Anxiety and Depression Scale and a visual analog scale to measure the patient's anxiety.

RESULTS

It was found that, on average, anxiety levels were lower in the intervention group on both the visual analog scale and Hospital Anxiety and Depression Scale. However, the findings did not reach statistical significance, p < .05.

CONCLUSION

On the basis of existing literature, preprocedure education has been shown to decrease patient anxiety. This study aimed to determine whether an additional educational intervention impacted anxiety in patients undergoing SRS for metastatic cancer. Although we found that anxiety levels were decreased in the intervention group, this finding did not reach statistical significance. A larger randomized study is needed to confirm the efficacy of such an intervention in this unique patient population.

Discovery of additional brain metastases on the day of stereotactic radiosurgery: risk factors and outcomes

OBJECTIVE High-resolution double-dose gadolinium-enhanced Gamma Knife (GK) radiosurgery-planning MRI (GK MRI) on the day of GK treatment can detect additional brain metastases undiagnosed on the prior diagnostic MRI scan (dMRI), revealing increased intracranial disease burden on the day of radiosurgery, and potentially necessitating a reevaluation of appropriate management. The authors identified factors associated with detecting additional metastases on GK MRI and investigated the relationship between detection of additional metastases and postradiosurgery patient outcomes. METHODS The authors identified 326 patients who received GK radiosurgery at their institution from 2010 through 2013 and had a prior dMRI available for comparison of numbers of brain metastases. Factors predictive of additional brain metastases on GK MRI were investigated using logistic regression analysis. Overall survival was estimated by Kaplan-Meier method, and postradiosurgery distant intracranial failure was estimated by cumulative incidence measures. Multivariable Cox proportional hazards model and Fine-Gray regression modeling assessed potential risk factors of overall survival and distant intracranial failure, respectively. RESULTS The mean numbers of brain metastases (SD) on dMRI and GK MRI were 3.4 (4.2) and 5.8 (7.7), respectively, and additional brain metastases were found on GK MRI in 48.9% of patients. Frequencies of detecting additional metastases for patients with 1, 2, 3-4, and more than 4 brain metastases on dMRI were 29.5%, 47.9%, 55.9%, and 79.4%, respectively (p < 0.001). An index brain metastasis with a diameter greater than 1 cm on dMRI was inversely associated with detecting additional brain metastases, with an adjusted odds ratio of 0.57 (95% CI 0.4-0.9, p = 0.02). The median time between dMRI and GK MRI was 22 days (range 1-88 days), and time between scans was not associated with detecting additional metastases. Patients with additional brain metastases did not have larger total radiosurgery target volumes, and they rarely had an immediate change in management (abortion of radiosurgery or addition of whole-brain radiation therapy) due to detection of additional metastases. Patients with additional metastases had a higher incidence of distant intracranial failure than those without additional metastases (p = 0.004), with an adjusted subdistribution hazard ratio of 1.4 (95% CI 1.0-2.0, p = 0.04). Significantly worse overall survival was not detected for patients with additional brain metastases on GK MRI (log-rank p = 0.07), with the relative adjusted hazard ratio of 1.07, (95% CI 0.81-1.41, p = 0.65). CONCLUSIONS Detecting additional brain metastases on GK MRI is strongly associated with the number of brain metastases on dMRI and inversely associated with the size of the index brain metastasis. The discovery of additional brain metastases at time of GK radiosurgery is very unlikely to lead to aborting radiosurgery but is associated with a higher incidence of distant intracranial failure. However, there is not a significant difference in survival. ▪ CLASSIFICATION OF EVIDENCE Type of question: prognostic; study design: retrospective cohort trial; evidence: Class IV.

Isotoxic radiosurgery planning for brain metastases

PURPOSE/OBJECTIVE(S)

Radionecrosis (RN) has previously been correlated with radiosurgery (RS) dose, lesion volume, and the volume of the brain receiving specific doses, i.e. V10-14Gy. A knowledge-based individualized estimation of the optimum RS dose has been derived based on lesional volume and brain toxicity parameters.

METHODS AND MATERIALS

A prediction model for brain toxicity parameters and estimation of the optimum RS dose was derived using 30 historical linac-based dynamic conformal arc RS plans for single brain metastases (BM) (0.2-20.3cc) with risk-adapted dose prescription ranging from 15 to 24Gy. Derivation of the model followed a three-step process: (1) Derivation of formulas for the prediction of brain toxicity parameters V10-18Gy; (2) Establishing the relationship of the coefficients used for the prediction of V12Gy with prescription dose; (3) Derivation of the optimum prescription dose for a given maximum V12Gy as a function of a given lesion volume. Model validation was performed on 65 new patients with 138 lesions (44 with multiple BM) treated with non-coplanar volumetric modulated stereotactic arc treatment (VMAT).

RESULTS

A linear dependence with the PTV size was found for all investigated brain toxicity parameters (V10-18Gy). Individualized RS prescription doses can be calculated for any given PTV size based on a linear relationship between V12Gy and PTV size, according to the formula PD=[V12Gy+0.96+(1.44×PTV)]/[0.12+(0.12×PTV)]. A very good correlation (R(2)=0.991) was found between the predicted V12Gy and the resulting V12Gy in 65 new patients with 138 lesions treated with non-coplanar VMAT technique in our clinic.

CONCLUSIONS

A simple formula is proposed for estimation of the optimal individual RS dose for any given lesion volume for patients with (multiple) BM. This formula is based on calculation of the brain toxicity parameter, V12Gy, for the normal brain minus PTV.

Overview of PET Tracers for Brain Tumor Imaging

This article provides an overview of the key considerations for the development and application of molecular imaging agents for brain tumors and the major classes of PET tracers that have been used for imaging brain tumors in humans. The mechanisms of uptake, biological implications, primary applications, and limitations of PET tracers in neuro-oncology are reviewed. The available data indicate that several of these classes of tracers, including radiolabeled amino acids, have imaging properties superior to those of (18)F-fluorodeoxyglucose, and can complement contrast-enhanced magnetic resonance imaging in the evaluation of brain tumors.

Single-Isocenter Frameless Volumetric Modulated Arc Radiosurgery for Multiple Intracranial Metastases

BACKGROUND

Stereotactic radiosurgery (SRS) is a well-accepted treatment for patients with intracranial metastases, but outcomes with volumetric modulated arc radiosurgery (VMAR) are poorly described.

OBJECTIVE

To report our initial clinical experience applying a novel single-isocenter technique to frameless VMAR for simultaneous treatment of multiple intracranial metastases.

METHODS

We performed a retrospective analysis of 15 patients undergoing frameless VMAR for multiple intracranial metastases using a single, centrally located isocenter in the period 2009 and 2011. Of these, 3 patients were treated for progressive or recurrent intracranial disease. A total of 62 metastases (median, 3 per patient; range, 2-13) were treated to a median dose of 20 Gy (range, 15-30 Gy). Three patients were treated with fractionated SRS. Follow-up including clinical examination and magnetic resonance imaging (MRI) occurred every 3 months.

RESULTS

The median follow-up for all patients was 7.1 months (range, 1.1-24.3), with 11 patients (73.3%) followed until death. For the remaining 4 patients alive at the time of analysis, the median follow-up was 19.6 months (range, 9.2-24.3). Local control at 6 and 12 months was 91.7% (95% confidence interval [CI], 84.6%-100.0%) and 81.5% (95% CI, 67.9%-100.0%), respectively. Regional failure was observed in 9 patients (60.0%), and 7 patients (46.7%) received salvage therapy. Overall survival at 6 months was 60.0% (95% CI, 40.3%-88.2%). Grade 3 or higher treatment-related toxicity was not observed. The median total treatment time was 7.2 minutes (range, 2.8-13.2 minutes).

CONCLUSION

Single-isocenter, frameless VMAR for multiple intracranial metastases is a promising technique that may provide similar clinical outcomes compared with conventional radiosurgery.

The Energy Index Does Not Affect Local Control of Brain Metastases Treated by Gamma Knife Stereotactic Radiosurgery

BACKGROUND

The energy index (EI) is a measure of dose homogeneity within a target volume calculated by the integral dose divided by the product of prescription dose and tumor volume.

OBJECTIVE

To assess whether a higher EI is associated with greater local control for brain metastases (BMs) treated by Gamma Knife radiosurgery (GKRS).

METHODS

We reviewed all patients treated with GKRS for BM at our institution between January 2009 and February 2014. Data on the prescription dose, prescription isodose line, minimum dose, mean dose, integral dose, tumor volume, and EI were collected. Tumor response was assessed by reviewing follow-up brain imaging studies and classified according to the Response Evaluation Criteria in Solid Tumors. Local control per lesion and dosimetric prognostic factors for local control were assessed by univariate and multivariate Cox proportional hazards regression analyses.

RESULTS

Of 213 patients treated, 126 had follow-up imaging available with a median follow-up of 6 months. Three hundred seventy-three individual tumors were analyzed. Of these, 133 showed a complete response, 157 showed a partial response, 46 remained stable, and 37 developed local failure. Tumors with EI ≥1.6 mJ·mL(-1)·Gy(-1) showed a higher rate of complete response. Local control rates at 6, 11, and 17 months were 95.4%, 86.5%, and 81.5%, respectively. On univariate analysis, the following factors were associated with higher rates of local failure: prescription doses of 16 and 18 Gy compared with a prescription dose of 20 Gy. The following factors were associated with a greater rate of local control: maximum dose and mean dose. On multivariate analysis, the only statistically significant factor associated with a greater rate of local failure was prescription dose of 16 Gy compared with 20 Gy.

CONCLUSION

GKRS for BM results in a high rate of local control with an 11-month rate of 86.5%. A higher EI was not significantly associated with a higher rate of local control on multivariate analysis. Prescription dose was found to be the only significant predictor of local control on multivariate analysis.

The Rationale for Targeted Therapies and Stereotactic Radiosurgery in the Treatment of Brain Metastases

Brain metastases are the most common intracranial malignancy. Many approaches, including radiation therapy, surgery, and cytotoxic chemotherapy, have been used to treat patients with brain metastases depending on the patient's disease burden and symptoms. However, stereotactic surgery (SRS) has revolutionized local treatment of brain metastases. Likewise, targeted therapies, including small-molecule inhibitors and monoclonal antibodies that target cancer cell metabolism or angiogenesis, have transformed managing systemic disease. Prospective data on combining these treatments for synergistic effect are limited, but early data show favorable safety and efficacy profiles. The combination of SRS and targeted therapy will further individualize treatment, potentially obviating the need for cytotoxic chemotherapy or whole-brain radiation. There is a great need to pursue research into these exciting modalities and novel combinations to further improve the treatment of patients with brain metastases. This article discusses reported and ongoing clinical trials assessing the safety and efficacy of targeted therapy during SRS.

IMPLICATIONS FOR PRACTICE

Treatment of patients with brain metastases requires a multidisciplinary approach. Stereotactic radiosurgery is increasingly used in the upfront setting to treat new brain metastasis. Targeted therapies have revolutionized systemic treatment of many malignancies and may sometimes be used as initial treatment in metastatic patients. There is sparse literature regarding safety and efficacy of combining these two treatment modalities. This article summarizes the supporting literature and highlights ongoing clinical trials in combining radiosurgery with targeted therapy.

Current treatment options of brain metastases and outcomes in patients with malignant melanoma

The prognosis for patients with melanoma who have brain metastases is poor, a median survival does not exceed 4-6 months. There are no uniform standards of treatment for patients with melanoma brain metastases (MBMs). The most preferred treatment approaches include local therapy - surgical resection and/or stereotactic radiosurgery (SRS). The role of whole brain radiotherapy (WBRT) as an adjuvant to local therapy is controversial. WBRT remains a palliative approach for those patients who have multiple MBMs with contraindications for surgery or SRS, or/and poor performance status, or/and very widespread extracranial metastases. Corticosteroids have been used in palliative treatment of MBMs as relief from symptoms related to intracranial pressure and edema. In recent years, the development of new systemic therapeutic strategies has been observed. Various modalities of systemic treatment include chemotherapy, immunotherapy and targeted therapy. Also, multimodality management in different combinations is a common strategy. Decisions regarding the use of specific treatment modalities are dependent on patient's performance status, and the extent of both intracranial and extracranial disease. This review summarizes current treatment options, indications and outcomes in patients with brain metastases from melanoma.

Lung cancer: Biology and treatment options

Lung cancer remains the leading cause of cancer mortality in men and women in the U.S. and worldwide. About 90% of lung cancer cases are caused by smoking and the use of tobacco products. However, other factors such as radon gas, asbestos, air pollution exposures, and chronic infections can contribute to lung carcinogenesis. In addition, multiple inherited and acquired mechanisms of susceptibility to lung cancer have been proposed. Lung cancer is divided into two broad histologic classes, which grow and spread differently: small-cell lung carcinomas (SCLCs) and non-small cell lung carcinomas (NSCLCs). Treatment options for lung cancer include surgery, radiation therapy, chemotherapy, and targeted therapy. Therapeutic-modalities recommendations depend on several factors, including the type and stage of cancer. Despite the improvements in diagnosis and therapy made during the past 25 years, the prognosis for patients with lung cancer is still unsatisfactory. The responses to current standard therapies are poor except for the most localized cancers. However, a better understanding of the biology pertinent to these challenging malignancies, might lead to the development of more efficacious and perhaps more specific drugs. The purpose of this review is to summarize the recent developments in lung cancer biology and its therapeutic strategies, and discuss the latest treatment advances including therapies currently under clinical investigation.

Steroid and anticonvulsant prophylaxis for stereotactic radiosurgery: Large variation in physician recommendations

PURPOSE/OBJECTIVE(S)

The risk of developing symptomatic edema or seizure following stereotactic radiosurgery (SRS) is poorly defined, and many practitioners prescribe prophylactic corticosteroids and/or anticonvulsants. Because there are no clear guidelines regarding appropriate use, we sought to characterize prescribing practices and factors associated with these recommendations.

METHODS AND MATERIALS

We conducted a 1-time, internet-based survey among 500 randomly selected radiation oncologists self-described as specializing in central nervous system diseases who were registered in the American Society for Radiation Oncology directory. Physicians were contacted by e-mail and invited to complete the 22-question survey.

RESULTS

The response rate was 32% (n = 161). Sixty-six percent of respondents had been in practice for >10 years, and 45% of respondents practiced at an academic medical center. During/after SRS, 53% of respondents "always" or "usually" recommended corticosteroids, whereas 47% "never," "rarely," or "sometimes" recommended them. When prescribing corticosteroids, the recommended duration of use was <1 week, 1-2 weeks, or >2 weeks among 49%, 33%, and 18% of respondents, respectively. Respondents who worked in an academic medical center were less likely to prescribe corticosteroids, although this did not reach significance (P = .09). Seizure prophylaxis was less common overall, as 79% of respondents "rarely" or "never" prescribed anticonvulsants for SRS. Respondents who prescribed anticonvulsants more frequently had higher estimations of the risk of seizure within 2 weeks of SRS (P < .001), and their recommended duration of anticonvulsant use was <1 week, 1-2 weeks, and >2 weeks among 35%, 25%, and 41% of respondents, respectively.

CONCLUSIONS

There is extreme variation in physician recommendations regarding prophylactic corticosteroid and anticonvulsant use for patients undergoing SRS. Further investigation of the risks and benefits of these medications for SRS is warranted, which may promote guideline development and more patient-centered, rational prescribing practices.

Outcome of gamma knife radiosurgery for metastatic brain tumors derived from non-small cell lung cancer

The purpose of this study was to analyze outcomes in patients treated with gamma knife radiosurgery (GKS) for brain metastases from non-small cell lung cancer (NSCLC). We retrospectively reviewed the medical records of 817 patients who underwent GKS for brain metastases from NSCLC between January 2002 and December 2012. A total of 1363 GKS procedures were performed for 2970 lesions. The median overall survival time from the initial GKS was 13 months and the salvage treatment-free survival from the first GKS was 6.5 months. Younger age (≤65 years), female sex, better RPA class, higher DS-GPA score, adenocarcinoma, synchronous onset, and lower integrated value of the "numbers and cumulative volume of tumors" were associated with better outcomes. Among the 601 patients with an available follow up image, the pattern of the first progression after initial GKS was the development of new lesions in 356 patients (59.2 %), regrowth of treated lesions in 106 patients (17.6 %), and leptomeningeal seeding (LMS) in 51 patients (8.5 %). Among the deceased, the last MRI performed prior to death was evaluated in 409 patients and showed progression in 263 patients (64.3 %), despite multiple salvage treatments. LMS was identified in 63 patients (15.4 %); a rate much higher than the incidence at first progression. Intracranial tumor burden, defined as the integrated value of the "number of the lesions and cumulative tumor volume", is a new prognostic factor of greater significance than tumor volume or number alone when analyzed as separate factors. Although the cause of death was not progression of brain lesions in the majority of patients, the brain lesions tended to have been persistently progressive in most patients, despite repeated salvage treatment. LMS is an important pattern of treatment failure, in addition to local progression or development of new lesions, particularly in the terminal phase of the disease.

Central nervous system cancers, version 2.2014. Featured updates to the NCCN Guidelines

The NCCN Guidelines for Central Nervous System Cancers provide multidisciplinary recommendations for the clinical management of patients with cancers of the central nervous system. These NCCN Guidelines Insights highlight recent updates regarding the management of metastatic brain tumors using radiation therapy. Use of stereotactic radiosurgery (SRS) is no longer limited to patients with 3 or fewer lesions, because data suggest that total disease burden, rather than number of lesions, is predictive of survival benefits associated with the technique. SRS is increasingly becoming an integral part of management of patients with controlled, low-volume brain metastases.

Postoperative stereotactic radiosurgery for resected brain metastasis

Despite therapeutic advances in management, the prognosis of patients with brain metastasis remains dismal. Treatment options include surgical resection, whole brain radiation therapy (WBRT), and stereotactic radiosurgery (SRS). Patients who undergo surgical resection typically receive WBRT as adjuvant therapy. However, several studies have demonstrated an association between WBRT and neurotoxicity. Thus, clinicians are increasingly delaying WBRT in favor of postoperative use of SRS. In this review, we will discuss the current literature exploring the efficacy and toxicity of postoperative SRS in the treatment of patients with resected brain metastasis.

Treatment of Large Brain Metastases With Stereotactic Radiosurgery

Introduction:

We report our series of patients with large brain metastases, >3 cm in diameter, who received stereotactic radiosurgery (SRS) as a component of their treatment, focusing on survival and intracranial recurrence rates.

Materials and Methods:

The brain tumor database was queried for patients treated with SRS for large brain metastases. Local recurrence (LR) and distant brain recurrence (DBR) rates were calculated using cumulative incidence analysis, and overall survival (OS) was calculated using Kaplan-Meier analysis. Patients were classified into 1 of the 4 groups based on treatment strategy: SRS alone, surgery plus SRS, SRS plus whole-brain radiation therapy (WBRT), and salvage SRS from more remote WBRT and/or surgery.

Results:

A total of 153 patients with 164 lesions were evaluated. The SRS alone was the treatment approach in 62 lesions, surgery followed by SRS to the resection bed (S + SRS) in 33, SRS + WBRT in 19, and salvage SRS in 50. There was no statistically significant difference in OS between the 4 treatment groups ( P = .06). Median survival was highest in patients receiving surgery + SRS (12.2 months) followed by SRS + WBRT (6.9 months), SRS alone (6.6 months), and salvage SRS (6.1 months). There was also no significant difference for LR rates between the groups at 12 months. No significant variables on univariate analysis were noted for LR. The 12-month DBR rates were highest in the S + SRS group (52%), followed by salvage SRS (31%), SRS alone (28%), and SRS + WBRT (13%; P = .03).

Conclusion:

There were no significant predictors for local control. Keeping in mind that patient numbers in the SRS + WBRT group are small, the addition of WBRT to SRS did not appear to significantly improve survival or local control, supporting the delayed use of WBRT for some patients to prevent potential side effects provided regular imaging surveillance and salvage therapy are utilized. Prospective studies are needed to optimize SRS treatment regimens for patients with large brain metastases.

Intraoperative radiotherapy to treat newly diagnosed solitary brain metastasis: initial experience and long-term outcomes

OBJECT

The authors assessed the feasibility of intraoperative radiotherapy (IORT) using a portable radiation source to treat newly diagnosed, surgically resected, solitary brain metastasis (BrM).

METHODS

In a nonrandomized prospective study, 23 patients with histologically confirmed BrM were treated with an Intrabeam device that delivered 14 Gy to a 2-mm depth to the resection cavity during surgery.

RESULTS

In a 5-year minimum follow-up period, progression-free survival from the time of surgery with simultaneous IORT averaged (± SD) 22 ± 33 months (range 1-96 months), with survival from the time of BrM treatment with surgery+IORT of 30 ± 32 months (range 1-96 months) and overall survival from the time of first cancer diagnosis of 71 ± 64 months (range 4-197 months). For the Graded Prognostic Assessment (GPA), patients with a score of 1.5-2.0 (n = 12) had an average posttreatment survival of 21 ± 26 months (range 1-96 months), those with a score of 2.5-3.0 (n = 7) had an average posttreatment survival of 52 ± 40 months (range 5-94 months), and those with a score of 3.5-4.0 (n = 4) had an average posttreatment survival of 17 ± 12 months (range 4-28 months). A BrM at the treatment site recurred in 7 patients 9 ± 6 months posttreatment, and 5 patients had new but distant BrM 17 ± 3 months after surgery+IORT. Six patients later received whole-brain radiation therapy, 7 patients received radiosurgery, and 2 patients received both treatments. The median Karnofsky Performance Scale scores before and 1 and 3 months after surgery were 80, 90, and 90, respectively; at the time of this writing, 3 patients remain alive with a CNS progression-free survival of > 90 months without additional BrM treatment.

CONCLUSIONS

The results of this study demonstrate the feasibility of resection combined with IORT at a dose of 14 Gy to a 2-mm peripheral margin to treat a solitary BrM. Local control, distant control, and long-term survival were comparable to those of other commonly used modalities. Surgery combined with IORT seems to be a potential adjunct to patient treatment for CNS involvement by systemic cancer.