Postoperative stereotactic radiosurgery to the resection cavity for large brain metastases: clinical outcomes, predictors of intracranial failure, and implications for optimal patient selection

Survival improvements in patients with melanoma brain metastases and leptomeningeal disease in the modern era: Insights from a nationwide study (2015-2022)

INTRODUCTION

Advances in modern therapies have improved outcomes for patients with melanoma brain metastases (MBM), though prognosis remains poor. The optimal treatment strategy for patients who do not meet clinical trial inclusion criteria is unclear.

METHODS

This study included all patients with MBM diagnosed in Denmark between 2015 and 2022, identified through the Danish Metastatic Melanoma Database (DAMMED) and local surgical and radiotherapy records. Data were collected from electronic patient records.

RESULTS

A total of 838 patients were included, with a median overall survival (OS) of 9.0 months. Of these, 112 (19.4 %) survived beyond 3 years post-diagnosis. Patients treated with immune checkpoint inhibitors (ICI) as first line treatment, specifically ipilimumab + nivolumab, demonstrated an intracranial overall response rate (icORR) of 46 % and a 2-year OS of 49 %. Those treated with BRAF/MEK inhibitors (BRAF/MEKi) had an icORR of 56 % but a 2-year OS of 20 %. Patients with leptomeningeal disease (LMD, n = 67) had a median OS of 8.4 months. Systemic therapy was associated with a superior OS for patients with LMD, though no survival benefit was seen with ICI compared to BRAF/MEKi. Among the 230 patients who underwent surgery, 30 received postoperative stereotactic radiosurgery (SRS); however, there was no difference in OS or intracranial progression-free survival between the groups.

CONCLUSION

A considerable proportion of patients with brain metastases diagnosed after 2015 survived more than 3 years. Patients with LMD appeared to obtain limited benefit of ICI with only few patients alive > 3 years post-diagnosis.

Stereotactic radiotherapy of intracranial tumor beds on a ring-mounted Halcyon LINAC

PURPOSE

This study sought to evaluate the feasibility and efficacy of the Halcyon Ring Delivery System (RDS) for delivering stereotactic radiotherapy (SRT) treatments for intracranial tumors beds.

METHODS

Ten previously treated brain SRT patients for 30 Gy in five fractions with non-coplanar HyperArc plans on TrueBeam (6MV-FFF) were replanned on Halcyon (6MV-FFF) using the same number of arcs and Eclipse's AcurosXB dose engine. Plan quality evaluation metrics per SRT protocol included: PTV coverage, GTV dose (minimum and mean), target conformity indices (CI), heterogeneity index (HI), gradient index (GI), maximum dose 2 cm away from the PTV (D2cm), and doses to organs-at-risk (OAR). Additionally, patient-specific quality assurance (QA) results and beam-on-time (BOT) were analyzed.

RESULTS

The Halcyon RDS provided highly conformal SRT plans for intracranial tumor beds with similar dose to target. When benchmarked against clinically delivered HyperArc plans, target coverage, CI(s) and HI were statistically similar. The Halcyon plans saw no statistical difference in maximum OAR doses to the brainstem, spinal cord, and cochlea. Due to the machine's coplanar geometry, the Halcyon plans showed a decrease in optic pathway dose (0.75 Gy vs. 2.08 Gy, p = 0.029). Overall, Halcyon's coplanar geometry resulted in a larger GI (3.33 vs. 2.72, p = 0.008) and a larger D2cm (39.59% vs. 29.07%, p < 0.001). In this cohort, multiple cases had the PTV and the optic pathway in the same axial plane. In one such instance, the PTV was <2 cm away from the optic pathway but even at this close proximity OAR, Halcyon still adequately spared the optic pathway. Additionally, the Halcyon's geometry provided slightly larger amount of normal brain dose receiving 24.4 Gy (8.99 cc vs. 7.36 cc) and 28.8 Gy (2.9 cc vs. 2.5 cc), although statistically insignificant. The Halcyon plans achieved similar delivery accuracy, quantified by patient-specific QA results evaluated with a 2%/2 mm gamma criteria (99.42% vs. 99.70%). For both plans, independent Monte Carlo second checks calculation agreed within 1%. Average Halcyon BOT was slightly higher by 0.35 min (p = 0.045), however, due to the one-step patient set-up and verification overall estimated treatment times on Halcyon were lower compared to HyperArc treatments (7.61 min vs. 10.26 min, p < 0.001).

CONCLUSIONS

When benchmarked against clinically delivered HyperArc treatments, the Halcyon brain SRT plans provided similar plan quality and delivery accuracy but achieved faster overall treatment times. We have started treating select brain SRT patients on the Halcyon RDS for patients having tumor beds greater than 1 cm in diameter with the closest OAR distance of greater than 2 cm away from the target. We recommend other clinics to consider commissioning SRT treatments on their Halcyon systems-allowing including remote Halcyon-only clinics to provide exceptionally high-quality therapeutic brain SRT treatments to an otherwise underserved patient cohort.

Hypofractionated stereotactic radiotherapy (HFSRT) versus single fraction stereotactic radiosurgery (SRS) to the resection cavity of brain metastases after surgical resection (SATURNUS): study protocol for a randomized phase III trial

BACKGROUND

The brain is a common site for cancer metastases. In case of large and/or symptomatic brain metastases, neurosurgical resection is performed. Adjuvant radiotherapy is a standard procedure to minimize the risk of local recurrence and is increasingly performed as local stereotactic radiotherapy to the resection cavity. Both hypofractionated stereotactic radiotherapy (HFSRT) and single fraction stereotactic radiosurgery (SRS) can be applied in this case. Although adjuvant stereotactic radiotherapy to the resection cavity is widely used in clinical routine and recommended in international guidelines, the optimal fractionation scheme still remains unclear. The SATURNUS trial prospectively compares adjuvant HFSRT with SRS and seeks to detect the superiority of HFSRT over SRS in terms of local tumor control.

METHODS

In this single center two-armed randomized phase III trial, adjuvant radiotherapy to the resection cavity of brain metastases with HFSRT (6 - 7 × 5 Gy prescribed to the surrounding isodose) is compared to SRS (1 × 12-20 Gy prescribed to the surrounding isodose). Patients are randomized 1:1 into the two different treatment arms. The primary endpoint of the trial is local control at the resected site at 12 months. The trial is based on the hypothesis that HFSRT is superior to SRS in terms of local tumor control.

DISCUSSION

Although adjuvant stereotactic radiotherapy after resection of brain metastases is considered standard of care treatment, there is a need for further prospective research to determine the optimal fractionation scheme. To the best of our knowledge, the SATURNUS study is the only randomized phase III study comparing different regimes of postoperative stereotactic radiotherapy to the resection cavity adequately powered to detect the superiority of HFSRT regarding local control.

TRIAL REGISTRATION

The study was retrospectively registered with ClinicalTrials.gov, number NCT05160818, on December 16, 2021. The trial registry record is available on  https://clinicaltrials.gov/study/NCT05160818 . The presented protocol refers to version V1.3 from March 21, 2021.

Neurotoxicity from Old and New Radiation Treatments for Brain Tumors

Research regarding the mechanisms of brain damage following radiation treatments for brain tumors has increased over the years, thus providing a deeper insight into the pathobiological mechanisms and suggesting new approaches to minimize this damage. This review has discussed the different factors that are known to influence the risk of damage to the brain (mainly cognitive disturbances) from radiation. These include patient and tumor characteristics, the use of whole-brain radiotherapy versus particle therapy (protons, carbon ions), and stereotactic radiotherapy in various modalities. Additionally, biological mechanisms behind neuroprotection have been elucidated.

Anti-Hormonal Therapy in Breast Cancer and Its Effect on the Blood-Brain Barrier

The molecular receptor status of breast cancer has implications for prognosis and long-term metastasis. Although metastatic luminal B-like, hormone-receptor-positive, HER2−negative, breast cancer causes brain metastases less frequently than other subtypes, though tumor metastases in the brain are increasingly being detected of this patient group. Despite the many years of tried and tested use of a wide variety of anti-hormonal therapeutic agents, there is insufficient data on their intracerebral effectiveness and their ability to cross the blood-brain barrier. In this review, we therefore summarize the current state of knowledge on anti-hormonal therapy and its intracerebral impact and effects on the blood-brain barrier in breast cancer.

Hypofractionated postoperative stereotactic radiotherapy for large resected brain metastases

PURPOSE

The aim of the present retrospective study was to report outcomes after hypofractionated stereotactic radiotherapy (HSRT) for resected brain metastases (BM).

PATIENTS AND METHODS

We reviewed results of patients with resected BM treated with postoperative HSRT (3×7.7Gy to the prescription isodose 70%) between May 2013 and June 2020. Local control (LC), distant brain control (DBC), overall survival (OS), leptomeningeal disease relapse (LMDR), and radiation necrosis (RN) occurrence were reported.

RESULTS

Twenty-two patients with 23 brain cavities were included. Karnofsky Performance status (KPS) was≥70 in 77.3%. Median preoperative diameter was 37mm [21.0-75.0] and median planning target volume (PTV) was 23 cm³ [9.9-61.6]. Median time from surgery to SRT was 69 days [7-101] and 48% of patients had a local relapse on pre-SRT imaging. Median follow-up was 17.5 months [1.6-95.9]. One and two-year LC rates were 60.9 and 52.2% respectively. One and 2-year DBC rates were 45.5 and 40.9%. Median OS was 16.5 months. Four patients (18.2%) presented LMDR during follow-up. RN occurred in 6 patients (27.2%). Three factors were associated with OS: ECOG-PS (P=0.009), KPS (P=0.04), and cystic metastasis before surgery (P=0.037). Several factors were related to RN occurrence: PTV diameter and volume, Normal brain V21, V21 and V24 isodoses volumes.

CONCLUSION

HSRT is the most widely used scheme for larger brain cavities after surgery. The optimal dose and scheme remain to be defined as well as the optimal delay between postoperative SRT and surgery. Dose escalation may be necessary, especially in case of subtotal resection.

Real-world data on melanoma brain metastases and survival outcome

Novel medical therapies have revolutionized outcome for patients with melanoma. However, patients with melanoma brain metastases (MBM) still have poor survival. Data are limited as these patients are generally excluded from clinical trials, wherefore real-world data on clinical outcome may support evidence-based treatment choices for patients with MBM. Patients diagnosed with MBM between 2008 and 2020 were included retrospectively. Patient characteristics, treatment, and outcome data were recorded from The Danish Metastatic Melanoma Database, pathology registries, electronic patient files, and radiation plans. Anti-programmed cell death protein 1 antibodies and the combination of BRAF/MEK-inhibitors were introduced in Denmark in 2015, and the cohort was split accordingly for comparison. A total of 527 patients were identified; 148 underwent surgical excision of MBM, 167 had stereotactic radiosurgery (SRS), 270 received whole-brain radiation therapy (WBRT), and 343 received systemic therapies. Median overall survival (mOS) for patients diagnosed with MBM before and after 2015 was 4.4 and 7.6 months, respectively. Patients receiving surgical excision as first choice of treatment had the best mOS of 10.9 months, whereas patients receiving WBRT had the worst outcome (mOS, 3.4 months). Postoperative SRS did not improve survival or local control after surgical excision of brain metastases. Of the 40 patients alive >3 years after diagnosis of MBM, 80% received immunotherapy at some point after diagnosis. Patients with meningeal carcinosis did not benefit from treatment with CPI. Outcome for patients with MBM has significantly improved after 2015, but long-term survivors are rare. Most patients alive >3 years after diagnosis of MBM received immunotherapy.

Stereotactic radiotherapy for brain oligometastases

Brain metastases, the most common metastases in adults, will develop in up to 40% of cancer patients, accounting for more than one-half of all intracranial tumors. They are most associated with breast and lung cancer, melanoma and, less frequently, colorectal and kidney carcinoma.

Magnetic resonance imaging (MRI) is the gold standard for diagnosis. For the treatment plan, computed tomography (CT ) images are co-registered and fused with a gadolinium-enhanced T1-weighted MRI where tumor volume and organs at risk are contoured. Alternatively, plain and contrast-enhanced CT scans are co-registered. Single-fraction stereotactic radiotherapy (SRT ) is used to treat patients with good performance status and up to 4 lesions with a diameter of 30 mm or less that are distant from crucial brain function areas. Fractionated SRT (2–5 fractions) is used for larger lesions, in eloquent areas or in proximity to crucial or surgically inaccessible areas and to reduce treatment-related neurotoxicity. The single-fraction SRT dose, which depends on tumor diameter, impacts local control. Fractionated SRT may encompass different schedules. No randomized trial data compared the safety and efficacy of single and multiple fractions. Both single-fraction and fractionated SRT provide satisfactory local control rates, tolerance, a low risk of transient acute adverse events and of radiation necrosis the incidence of which correlated with the irradiated brain volume.

Redistributing Central Target Dose Hot Spots for Hypofractionated Radiosurgery of Large Brain Tumors: A Proof-of-Principle Study

OBJECTIVE

The present proof-of-principle study investigated radiobiological effects of redistributing central target dose hot spots across different treatment fractions during hypofractionated stereotactic radiosurgery (HSRS) of large intracranial tumors.

METHODS

Redistribution of central target dose hot spots during HSRS was simulated, and its effects were evaluated in eight cases of brain metastases. To assess dose variations in the target across N number of treatment fractions, a generalized biologically effective dose (gBED) was formulated. The gBED enhancement ratio was defined as the ratio of gBED in the tested treatment plan (with central target dose hot spot redistributions across fractions) to gBED in the conventional treatment plan (without central target dose hot spot redistributions).

RESULTS

At a median α value of 0.3/Gy, the tested treatment plans resulted in average gBED increases of 15.6 ± 3.5% and 8.3 ± 1.8% for α/β ratios of 2 and 10 Gy, respectively. In comparison with conventional treatment plans, the differences in the Paddick conformity index and gradient index did not exceed 2%.

CONCLUSION

Redistributing central target dose hot spots across different treatment fractions during HSRS may be considered promising for enhancing gBED in the target. It may be beneficial for management of large intracranial neoplasms; thus, it warrants further clinical testing.

A matched-pair analysis of clinical outcomes after intracavitary cesium-131 brachytherapy versus stereotactic radiosurgery for resected brain metastases

OBJECTIVE

Adjuvant radiation therapy (RT), such as cesium-131 (Cs-131) brachytherapy or stereotactic radiosurgery (SRS), reduces local recurrence (LR) of brain metastases (BM). However, SRS is less efficacious for large cavities, and the delay between surgery and SRS may permit tumor repopulation. Cs-131 has demonstrated improved local control, with reduced radiation necrosis (RN) compared to SRS. This study represents the first comparison of outcomes between Cs-131 brachytherapy and SRS for resected BM.

METHODS

Patients with BM treated with Cs-131 and SRS following gross-total resection were retrospectively identified. Thirty patients who underwent Cs-131 brachytherapy were compared to 60 controls who received SRS. Controls were selected from a larger cohort to match the patients treated with Cs-131 in a 2:1 ratio according to tumor size, histology, performance status, and recursive partitioning analysis class. Overall survival (OS), LR, regional recurrence, distant recurrence (DR), and RN were compared.

RESULTS

With a median follow-up of 17.5 months for Cs-131-treated and 13.0 months for SRS-treated patients, the LR rate was significantly lower with brachytherapy; 10% for the Cs-131 cohort compared to 28.3% for SRS patients (OR 0.281, 95% CI 0.082-0.949; p = 0.049). Rates of regional recurrence, DR, and OS did not differ significantly between the two cohorts. Kaplan-Meier analysis with log-rank testing showed a significantly higher likelihood of freedom from LR (p = 0.027) as well as DR (p = 0.018) after Cs-131 compared to SRS treatment (p = 0.027), but no difference in likelihood of OS (p = 0.093). Six (10.0%) patients who underwent SRS experienced RN compared to 1 (3.3%) patient who received Cs-131 (p = 0.417).

CONCLUSIONS

Postresection patients with BM treated with Cs-131 brachytherapy were more likely to achieve local control compared to SRS-treated patients. This study provides preliminary evidence of the potential of Cs-131 to reduce LR following gross-total resection of single BM, with minimal toxicity, and suggests the need for a prospective study to address this question.

Post-operative management of brain metastases: GRADE-based clinical practice recommendations on behalf of the Italian Association of Radiotherapy and Clinical Oncology (AIRO)

PURPOSE

To perform a systematic review of the current level of evidence on post-operative management following brain metastasectomy (namely: adjuvant stereotactic radiosurgery, whole brain radiotherapy or observation), and to propose a GRADE-based dedicated recommendation to inform Radiation Oncologists' clinical practice.

METHODS

A panel of expert Radiation Oncologists from the Italian Association of Radiotherapy and Clinical Oncology had defined the search question per the PICO methodology. Electronic databases were independently screened; the Preferred Reporting Items for Systematic Reviews and Meta-Analyses was adopted. The individual and pooled hazard ratios with 95% confidence intervals (CI), as well as the pooled risk ratio (RR) were calculated using a fixed- or random-effects model.

RESULTS

Eight full-texts were retrieved: six retrospective studies and two randomized clinical trials. Outcomes of benefit and damage were analyzed for SRS + observation (PICO A) and SRS + WBRT. SRS allowed for increased rates of local control when compared to both observation and WBRT, while evidence was less conclusive for distant brain control, leptomeningeal disease control and overall survival. In the SRS, the incidence of severe radionecrosis was higher as compared to WBRT, despite neurocognitive deterioration rates were lower. Overall, SRS seems to favorably compare with observation and whole brain RT, despite the level of evidence for the recommendation was low and very low, respectively.

CONCLUSION

Despite low level of evidence, the panel concluded that the risk/benefit ratio probably favors adjuvant SRS as compared to the observation and whole brain RT as adjuvant treatments following brain metastasectomy (5 votes/5 participants, 100% attendance).

Resection and Surgically Targeted Radiation Therapy for the Treatment of Larger Recurrent or Newly Diagnosed Brain Metastasis: Results From a Prospective Trial

Introduction Achieving durable local control (LC) for larger (e.g., >2-3 cm) brain metastasis whether newly diagnosed or recurrent remains problematic. Resection (R) alone is typically insufficient and adding radiation therapy (RT) still results in a 12-month recurrence rate of 20% or more in many series. Hypothesizing that R plus immediate radiation utilizing brachytherapy may improve outcomes for this cohort of patients, we designed and prospectively evaluated a permanently implanted surgically targeted radiation therapy (STaRT) device consisting of cesium-131 (Cs-131) seeds positioned within a collagen carrier (GammaTile, GT Medical Technologies, Tempe, AZ). The device was designed to prevent direct source-to-brain contact and maintain inter-source spacing after closure. Methods This was a subgroup analysis of a cohort of patients with either recurrent or previously untreated brain metastases enrolled in a prospective, multi-histology single-arm trial (ClinicalTrials.gov, NCT#03088579), conducted between February 2013 and February 2018, of resection and tumor bed brachytherapy with Cs-131 containing permanently implanted collagen tiles to deliver 60 Gray (Gy) at .5 cm depth. No additional local therapy was given without progression. Results A total of 16 metastases in 11 patients were treated; 12 tumors were recurrent and four were previously untreated. The median preoperative maximum diameter was 3.2 cm (range: 1.9-5.1 cm). Histology was seven breasts, six lungs, and three sarcomas. The median age was 60 years (range: 41-80 years); the Karnofsky Performance Status (KPS) was 70 (range: 70-90). The cohort consisted of seven females and four males. The mean time for implantation completion was five minutes. The median overall survival (OS) was 9.3 months. At a median radiographic follow-up of 9.5 months' treatment, site progression was found in 1/16 (6%) at 10.9 months, and the median treatment site time-to-progression (TTP) has not been reached [95% confidence interval (CI): >10.9 months]. At 12 months, the Kaplan-Meier (K-M) estimates for LC after R+STaRT for all tumors was 83%; for previously untreated tumors, LC at 12 months was 100% and for recurrent tumors, it was 80%. Two tumor beds (12.5%) experienced radiation brain changes: one had grade two and the other grade three. No surgical adverse events occurred. Conclusion In this single-arm precommercial study, R+STaRT demonstrated excellent safety and LC in this cohort. The device has recently received FDA clearance for use in newly diagnosed and recurrent brain metastasis, and randomized clinical trials vs. standard of care treatments in both settings are scheduled to open in 2020.

Management of melanoma brain metastases: Evidence-based clinical practice guidelines by Cancer Council Australia

INTRODUCTION

The brain is a common site of metastatic disease for patients with advanced melanoma. Brain metastasis portends a poor prognosis, often causing deterioration in neurological function and quality of life, and leading to neurological death. Treatment approaches including surgery, radiotherapy and systemic therapy can lead to better control of this problem. Therefore, appropriate guidelines for the management of melanoma brain metastases need to be established, with regular updating when new treatment options become available.

METHODS

A multidisciplinary working party established by Cancer Council Australia has produced up-to-date, evidence-based clinical practice guidelines for the management of melanoma. After selecting key clinical questions, a comprehensive literature search for relevant studies was conducted, followed by systematic review of those studies. Data were summarised and the evidence was assessed, leading to the development of recommendations.

MAIN RECOMMENDATIONS

Symptomatic lesions are best treated with surgery, when possible; this provides safe and effective local control. For patients with single or a small number of asymptomatic brain metastases, stereotactic radiotherapy is recommended, but in asymptomatic patients who have not previously received systemic treatment, drug therapy can be considered as a first-line treatment option. Whole brain radiotherapy may provide palliative benefits in patients with multiple brain metastases. Whenever possible, melanoma patients with brain metastases should be managed by a multidisciplinary team of melanoma specialists that considers the optimal combination and sequencing of surgery, radiotherapy and systemic therapy.

A Dose-Response Model of Local Tumor Control Probability After Stereotactic Radiosurgery for Brain Metastases Resection Cavities

Purpose

Recent randomized controlled trials evaluating stereotactic surgery (SRS) for resected brain metastases question the high rates of local control previously reported in retrospective studies. Tumor control probability (TCP) models were developed to quantify the relationship between radiation dose and local control after SRS for resected brain metastases.

Methods and Materials

Patients with resected brain metastases treated with SRS were evaluated retrospectively. Melanoma, sarcoma, and renal cell carcinoma were considered radio-resistant histologies. The planning target volume (PTV) was the region of enhancement on T1 post-gadolinium magnetic resonance imaging plus a 2-mm uniform margin. The primary outcome was local recurrence, defined as tumor progression within the resection cavity. Cox regression evaluated predictors of local recurrence. Dose-volume histograms for the PTV were obtained from treatment plans and converted to 3-fraction equivalent doses (α/β = 12 Gy). TCP models evaluated local control at 1-year follow-up as a logistic function of dose-volume histogram data.

Results

Among 150 cavities, 41 (27.3%) were radio-resistant. The median PTV volume was 14.6 mL (range, 1.3-65.3). The median prescription was 21 Gy (range, 15-25) in 3 fractions (range, 1-5). Local control rates at 12 and 24 months were 86% and 82%. On Cox regression, larger cavities (PTV > 12 cm³) predicted increased risk of local recurrence (P = .03). TCP modeling demonstrated relationships between improved 1-year local control and higher radiation doses delivered to radio-resistant cavities. Maximum PTV doses of 30, 35, and 40 Gy predicted 78%, 89%, and 94% local control among all radio-resistant cavities, versus 69%, 79%, and 86% among larger radio-resistant cavities.

Conclusions

After SRS for resected brain metastases, larger cavities are at greater risk of local recurrence. TCP models suggests that higher radiation doses may improve local control among cavities of radio-resistant histology. Given maximum tolerated doses established for single-fraction SRS, fractionated regimens may be required to optimize local control in large radio-resistant cavities.

Evaluatıon of hypofractıonated stereotactıc radıotherapy (HFSRT) to the resectıon cavıty after surgıcal resectıon of braın metastases: A sıngle center experıence

INTRODUCTON

Adjuvant radiotherapy after surgical resection is used for the treatment of patients with brain metastasis. In this study, we assessed the use of adjuvant hypofractionated stereotactic radiotherapy (HFSRT) to the resection cavity for the management of patients with brain metastasis.

MATERIALS AND METHODS

A total of 28 patients undergoing surgical resection for their brain metastasis were treated using HFSRT to the resection cavity. A total HFSRT dose of 25-30 Gray (Gy) was delivered in 5 consecutive daily fractions. Patients were retrospectively assessed for toxicity, local control, and survival outcomes. Kaplan-Meier method and log-rank test were used for statistical analysis.

RESULTS

Median planning target volume (PTV) was 27.2 cc (range: 6-76.1 cc). At a median follow-up time of 11 months (range: 2-21 months.), 1-year local control rate was 85.7%, and 1-year distant failure rate was 57.1% (16 patients). Median overall survival was 15 months from HFSRT. Higher recursive partitioning analysis class (P = 0.01) and the presence of extracranial metastases (P = 0.02) were associated with decreased overall survival on statistical analysis. There was no radiation necrosis observed during follow-up.

CONCLUSION

HFSRT to the resection cavity offers a safe and effective adjuvant treatment for patients undergoing surgical resection of brain metastasis. With comparable local control rates, HFSRT may serve as a viable alternative to whole brain irradiation.

Efficacy and Tolerance of Post-operative Hypo-Fractionated Stereotactic Radiotherapy in a Large Series of Patients With Brain Metastases

Purpose: The aim of this study was to assess, in a large series, the efficacy and tolerance of post-operative adjuvant hypofractionated stereotactic radiation therapy (HFSRT) for brain metastases (BMs).

Materials and Methods: Between July 2012 and January 2017, 160 patients from 2 centers were operated for BM and treated by HFSRT. Patients had between 1 and 3 BMs, no brainstem lesions or carcinomatous meningitis. The primary endpoint was local control. Secondary endpoints were distant brain control, overall survival (OS) and tolerance to HFSRT.

Results: 73 patients (46%) presented with non-small cell lung cancer (NSCLC), 23 (14%) had melanoma and 21 (13%) breast cancer. Median age was 58 years (range, 22–83 years). BMs were synchronous in 50% of the cases. The most frequent prescription regimens were 24 Gy in 3 fractions (n = 52, 33%) and 30 Gy in 5 fractions (n = 37, 23%). Local control rates at 1 and 2 years were 88% [95%CI, 81–93%] and 81% [95%CI, 70–88%], respectively. Distant control rate at 1 year was 48% [95%CI, 81–93%]. In multivariate analysis, primary NSCLC was associated with a significant reduction in the risk of death compared to other primary sites (HR = 0.57, p = 0.007), the number of extra-cerebral metastatic sites (HR = 1.26, p = 0.003) and planning target volumes (HR = 1.15, p = 0.012) were associated with a lower OS. There was no prognostic factor of time to local progression. Median OS was 15.2 months [95%CI, 12.0–17.9 months] and the OS rate at 1 year was 58% [95% CI, 50–65%]. Salvage radiotherapy was administered to 72 patients (45%), of which 49 received new HFSRT. Ten (7%) patients presented late grade 2 and 4 (3%) patients late grade 3 toxicities. Thirteen (8.9%) patients developed radiation necrosis.

Conclusions: This large multicenter retrospective study shows that HFSRT allows for good local control of metastasectomy tumor beds and that this technique is well-tolerated by patients.

Impact of regular magnetic resonance imaging follow-up after stereotactic radiotherapy to the surgical cavity in patients with one to three brain metastases

BACKGROUND

Administering stereotactic radiotherapy to the surgical cavity and thus omitting postoperative whole brain radiotherapy (WBRT) is a favored strategy in limited metastatic brain disease. Little is known about the impact of regular magnetic resonance imaging follow-up (MRI FU) in such patient cohorts. The aim of this study is to examine the impact of regular MRI FU and to report the oncological outcomes of patients with one to three brain metastases (BMs) treated with stereotactic radiosurgery (SRS) or hypo-fractionated stereotactic radiotherapy (HFSRT) to the surgical cavity.

METHODS

We retrospectively analyzed patients who received SRS or HFSRT to the surgical cavity after resection of one to two BMs. Additional, non-resected BMs were managed with SRS alone. Survival was estimated by the Kaplan-Meier method. Prognostic factors were examined with the log-rank test and Cox proportional hazards model. Regular MRI FU was defined as performing a brain MRI 3 months after radiotherapy (RT) and/or performing ≥1 brain MRI per 180 days. Primary endpoint was local control (LC). Secondary endpoints were distant brain control (DBC), overall survival (OS) and the correlation between regular MRI FU and overall survival (OS), symptom-free survival (SFS), deferment of WBRT and WBRT-free survival (WFS).

RESULTS

Overall, 75 patients were enrolled. One, 2 and 3 BMs were seen in 63 (84%), 11 (15%) and 1 (1%) patients, respectively. Forty (53%) patients underwent MRI FU 3 months after RT and 38 (51%) patients received ≥1 brain MRI per 180 days. Median OS was 19.4 months (95% CI: 13.2-25.6 months). Actuarial LC, DBC and OS at 1 year were 72% (95% CI: 60-83%), 60% (95% CI: 48-72%) and 66% (95% CI: 53-76%), respectively. A planning target volume > 15 cm³ (p = 0.01), Graded Prognostic Assessment (GPA) score (p = 0.001) and residual tumor after surgery (p = 0.008) were prognostic for decreased OS in multivariate analysis. No significant correlation between MRI FU at 3 months and OS (p = 0.462), SFS (p = 0.536), WFS (p = 0.407) or deferment of WBRT (p = 0.955) was seen. Likewise, performing ≥1 MRI per 180 days had no significant impact on OS (p = 0.954), SFS (p = 0.196), WFS (p = 0.308) or deferment of WBRT (p = 0.268).

CONCLUSION

Our results regarding oncological outcomes consist with the current data from the literature. Surprisingly, regular MRI FU did not result in increased OS, SFS, WFS or deferment of WBRT in our cohort consisting mainly of patients with a single and resected BM. Therefore, the impact of regular MRI FU needs prospective evaluation.

TRIAL REGISTRATION

Project ID: 2017-00033, retrospectively registered.

Tumor Cavity Recurrence after Stereotactic Radiosurgery of Surgically Resected Brain Metastases: Implication of Deviations from Contouring Guidelines

BACKGROUND

Significant heterogeneity exists in target volumes for postoperative stereotactic radiosurgery (SRS) for brain metastases. A set of contouring guidelines was recently published, and we investigated the impact of deviations.

METHODS

Patients (n = 41) undergoing single-fraction Gamma Knife SRS following surgical resection of brain metastases from 2011 to 2017 were retrospectively reviewed. SRS included the entire contrast-enhancing cavity with heterogeneity in inclusion of the surgical tract and no routine margin along the dura or clinical target volume margin. Follow-up MR imaging was fused with SRS plans to assess patterns of failure.

RESULTS

The median follow-up was 11.1 months with a median prescription of 18 Gy. There were 5 local failures: infield (n = 3, 60%), surgical tract (n = 1, 20%), and marginal > 5 mm from the resection cavity (n = 1, 20%). No marginal failures < 5 mm or dural margin failures were noted. For deep lesions (n = 13), 62% (n = 8) had the entire tract covered. The only tract recurrence was in a deep lesion without coverage of the surgical tract (n = 1/5).

CONCLUSION

In this small preliminary experience, despite no routine inclusion of the dural tract or bone flap, no failures were noted in these locations. Omission of the surgical tract in deep lesions may increase failure rates.

Single versus Multifraction Stereotactic Radiosurgery for Large Brain Metastases: An International Meta-analysis of 24 Trials

PURPOSE

Multifraction (MF) stereotactic radiosurgery (SRS) purportedly reduces radionecrosis risk over single-fraction (SF) SRS in the treatment of large brain metastases. The purpose of the current work is to compare local control (LC) and radionecrosis rates of SF-SRS and MF-SRS in the definitive (SF-SRS_D and MF-SRS_D) and postoperative (SF-SRS_P and MF-SRS_P) settings.

METHODS AND MATERIALS

Population, Intervention, Control, Outcomes, Study Design/Preferred Reporting Items for Systematic Reviews and Meta-analyses and Meta-analysis of Observational Studies in Epidemiology guidelines were used to select articles in which patients had "large" brain metastases (Group A: 4-14 cm³, or about 2-3 cm in diameter; Group B: >14 cm³, or about >3 cm in diameter); 1-year LC and/or rates of radionecrosis were reported; radiosurgery was administered definitively or postoperatively. Random effects meta-analyses using fractionation scheme and size as covariates were conducted. Meta-regression and Wald-type tests were used to determine the effect of increasing tumor size and fractionation on the summary estimate, where the null hypothesis was rejected for P < .05.

RESULTS

Twenty-four studies were included, published between 2008 and 2017, with 1887 brain metastases. LC random effects estimate at 1 year was 77.6% for Group A/SF-SRS_D and 92.9% for Group A/MF-SRS_D (P = .18). LC random effects estimate at 1 year was 77.1% for Group B/SF-SRS_D and 79.2% for Group B/MF-SRS_D (P = .76). LC random effects estimate at 1 year was 62.4% for Group B/SF-SRS_P and 85.7% for Group B/MF-SRS_P (P = .13). Radionecrosis incidence random effects estimate was 23.1% for Group A/SF-SRS_D and 7.3% for Group A/MF-SRS_D (P = .003). Radionecrosis incidence random effects estimate was 11.7% for Group B/SF-SRS_D and 6.5% for Group B/MF-SRS_D (P = .29). Radionecrosis incidence random effects estimate was 7.3% for Group B/SF-SRS_P and 7.5% for Group B/MF-SRS_P (P = .85). Metaregression assessing 1-year LC and radionecrosis as a continuous function of increasing tumor volume was not statistically significant.

CONCLUSIONS

Treatment for large brain metastases with MF-SRS regimens may offer a relative reduction of radionecrosis while maintaining or improving relative rates of 1-year LC compared with SF-SRS. These findings are hypothesis-generating and require validation by ongoing and planned prospective clinical trials.

Long-Term Survivorship Following Stereotactic Radiosurgery Alone for Brain Metastases: Risk of Intracranial Failure and Implications for Surveillance and Counseling

BACKGROUND

Historically, survival for even highly select cohorts of brain metastasis patients selected for SRS alone is <2 yr; thus, limited literature on risks of recurrence exists beyond 2 yr.

OBJECTIVE

To investigate the possibility that for subsets of patients the risk of intracranial failure beyond 2 yr is less than the commonly quoted 50% to 60%, wherein less frequent screening may be appropriate.

METHODS

As a part of our institutional radiosurgery database, we identified 132 patients treated initially with stereotactic radiosurgery (SRS) alone (± pre-SRS surgical resection) with at least 2 yr of survival and follow-up from SRS. Primary study endpoints were rates of actuarial intracranial progression beyond 2 yr, calculated using the Kaplan-Meier and Cox regression methods.

RESULTS

The median follow-up from the first course of SRS was 3.5 yr. Significant predictors of intracranial failure beyond 2 yr included intracranial failure before 2 yr (52% vs 25%, P < .01) and total SRS tumor volume ≥5 cc (51% vs 25%, P < .01). On parsimonious multivariate analysis, failure before 2 yr (HR = 2.2, 95% CI: 1.2-4.3, P = .01) and total SRS tumor volume ≥5 cc (HR = 2.3, 95% CI: 1.2-4.3, P = .01) remained significant predictors of intracranial relapse beyond 2 yr.

CONCLUSION

Relapse rates beyond 2 yr following SRS alone for brain metastases are low in patients who do not suffer intracranial relapse within the first 2 yr and with low-volume brain metastases, supporting a practice of less frequent screening beyond 2 yr. For remaining patients, frequent (every 3-4 mo) screening remains prudent, as the risk of intracranial failure after 2 yr remains high.

Local control and possibility of tailored salvage after hypofractionated stereotactic radiotherapy of the cavity after brain metastases resection

In patients undergoing surgical resection of brain metastases, the risk of local recurrence remains high. Adjuvant whole brain radiation therapy (WBRT) can reduce the risk of local relapse but fails to improve overall survival. At two tertiary care centers in Germany, a retrospective study was performed to evaluate the role of hypofractionated stereotactic radiotherapy (HFSRT) in patients with brain metastases after surgical resection. In particular, need for salvage treatment, for example, WBRT, surgery, or stereotactic radiosurgery (SRS), was evaluated. Both intracranial local (LF) and locoregional (LRF) failures were analyzed. A total of 181 patients were treated with HFSRT of the surgical cavity. In addition to the assessment of local control and distant intracranial control, we analyzed treatment modalities for tumor recurrence including surgical strategies and reirradiation. Imaging follow-up for the evaluation of LF and LRF was available in 159 of 181 (88%) patients. A total of 100 of 159 (63%) patients showed intracranial progression after HFSRT. A total of 81 of 100 (81%) patients received salvage therapy. Fourteen of 81 patients underwent repeat surgery, and 78 of 81 patients received radiotherapy as a salvage treatment (53% WBRT). Patients with single or few metastases distant from the initial site or with WBRT in the past were retreated by HFSRT (14%) or SRS, 33%. Some patients developed up to four metachronous recurrences, which could be salvaged successfully. Eight (4%) patients experienced radionecrosis. No other severe side effects (CTCAE≥3) were observed. Postoperative HFSRT to the resection cavity resulted in a crude rate for local control of 80.5%. Salvage therapy for intracranial progression was commonly needed, typically at distant sites. Salvage therapy was performed with WBRT, SRS, and surgery or repeated HFSRT of the resection cavity depending on the tumor spread and underlying histology. Prospective studies are warranted to clarify whether or not the sequence of these therapies is important in terms of quality of life, risk of radiation necrosis, and likelihood of neurological cause of death.

Very Large Metastases to the Brain: Retrospective Study on Outcomes of Surgical Management

BACKGROUND

The incidence of brain metastases is rising. To our knowledge, no published study focuses exclusively on brain metastases larger than 4 cm. We present our surgical outcomes for patients with brain metastases larger than 4 cm.

METHODS

This is a retrospective chart review of inpatient data at our institution from January 2006 to September 2015. Primary end points included overall survival, progression-free survival, and local recurrence rate.

RESULTS

Sixty-one patients had a total of 67 brain metastases larger than 4 cm: 52 were supratentorial and 15 were infratentorial. Forty-three patients underwent surgical resection. Average duration of disease freedom after resection was 4.79 months (range, 0-30 months). Excluding patients with residual on immediate postoperative magnetic resonance imaging, the average rate of local recurrence was 7 months (range, 1-14 months). Overall survival after surgery excluding patients who chose palliation in the immediate postoperative period averaged 8.76 months (range, 1-37 months). Thirty-five of 43 patients (81.4%) had stable or improved neurologic examinations postoperatively. Six patients (13.95%) developed surgical complications. There were 3 major complications (6.98%): 2 pseudomeningoceles required intervention and 1 postoperative hematoma required external ventricular drain placement. There were 3 minor complications (6.98%): 1 self-limited pseudomeningocele, 1 subgaleal fluid collection, and 1 postoperative seizure.

CONCLUSIONS

Surgery resulted in stable or improved neurologic examination in 81.4% of cases. On statistical analysis, significantly increased overall survival was noted in patients undergoing surgical resection, and those with higher Karnofsky Performance Scale and lower number of brain metastases at presentation. There is a need for further studies to evaluate management of brain metastases larger than 4 cm.

Linear accelerator-based radiosurgery and hypofractionated stereotactic radiotherapy for brain metastasis secondary to gynecologic malignancies: A single institution series examining outcomes of a rare entity

Objective

The use of SRS and fSRT to determine overall survival, tumor control, and local-disease free progression in patient diagnosed with gynecologic brain metastasis.

Methods

In this retrospective review, 11 patients aged 50 to 85 (median age of 71) were treated with linear accelerator-based SRS and hypofractionated SRT for brain metastasis secondary to gynecologic malignancies. In total, 16 tumors were treated from 2007 to 2017. Patients were treated to a median dose of 24 Gy (range 15 to 30 Gy) in 3 Fx (range 1 to 5). Median follow-up from SRS or SRT was 4 months (range 3–38 months).

Results

The actuarial 1-year overall survival rate was 26% with a median overall survival of 8 months. In addition, 1-year actuarial local control rate was 83.3% and the 1-year distant brain control rate was 31%. One patient experienced toxicity that presented as seizures after 7 months (due to minimal edema) that required anticonvulsants. There was no other acute or late treatment-related toxicity.

Conclusion: Linear-accelerator based SRS or fSRT is safe and effective for control of local tumor growth in brain metastases secondary to gynecologic malignancies. The course of disease remains aggressive as seen by poor overall survival and distant failure rate.

•

Brain Metastases as a result of gynecologic malignancies are rare, making up <3% of CNS metastasis.

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Improved systemic treatment and radiographic sensitivity has led to increased incidence of gynecologic brain metastasis.

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Stereotactic technique, including radiosurgery and radiotherapy, remain a safe, effective treatment option.

Postoperative radiosurgery for the treatment of metastatic brain tumor: Evaluation of local failure and leptomeningeal disease

In patients undergoing surgical resection of a metastatic brain tumor, whole brain radiation therapy reduces the risk of recurrence and neurologic death. Focal radiation has the potential to mitigate neurocognitive side effects. We present an institutional experience of postoperative radiosurgery for the treatment of brain metastases. A retrospective review of a prospectively maintained institutional radiosurgery database was performed for the years 2005-2015 identifying all adult patients treated with postoperative radiosurgery to the tumor bed. Primary endpoints include local recurrence and postoperative LMD. Kaplan-Meier curves and Cox regression were used to evaluate time to local recurrence and postoperative LMD. Ninety-one patients received adjuvant focal radiation for a brain metastasis. Median radiographic follow-up among patients who had not developed a local failure was 9 months. Of the 91 patients, 20 (22%) developed local recurrence and 32 (35%) experienced postoperative LMD. Freedom from local recurrence and LMD at 1 year was 84% and 69%, respectively. In multivariable models, predictors of local failure included the presence of more than one brain metastasis (HR = 2.65, p = .04) with a preoperative tumor diameter of >3 cm (HR = 4.16, p = .06) trending toward significance. There was a trend to a higher risk of LMD with >1 tumor (HR 2.07, p = .06) and breast cancer (HR 2.37, p = .07). More than one metastasis is an independent predictor of local and leptomeningeal failure following postoperative radiosurgery. The high rate of LMD was likely related to the liberal definition of LMD to include focal dural recurrences.

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

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

Diagnosis and treatment of brain metastases from solid tumors: guidelines from the European Association of Neuro-Oncology (EANO)

The management of patients with brain metastases has become a major issue due to the increasing frequency and complexity of the diagnostic and therapeutic approaches. In 2014, the European Association of Neuro-Oncology (EANO) created a multidisciplinary Task Force to draw evidence-based guidelines for patients with brain metastases from solid tumors. Here, we present these guidelines, which provide a consensus review of evidence and recommendations for diagnosis by neuroimaging and neuropathology, staging, prognostic factors, and different treatment options. Specifically, we addressed options such as surgery, stereotactic radiosurgery/stereotactic fractionated radiotherapy, whole-brain radiotherapy, chemotherapy and targeted therapy (with particular attention to brain metastases from non-small cell lung cancer, melanoma and breast and renal cancer), and supportive care.

Stereotactic Radiosurgery and Ipilimumab Versus Stereotactic Radiosurgery Alone in Melanoma Brain Metastases

Benefits of stereotactic radiosurgery (SRS) have been well established in melanoma brain metastases (MBM). Immunotherapy agents such as ipilimumab (ipi) have recently demonstrated clinical efficacy in advanced disease as well. The theoretical synergistic effects of combining these therapies in MBM have not been explored in detail, however, we conducted a systematic review with meta-analysis of studies that compared combined SRS and ipi versus SRS alone in MBM. Medical Literature Analysis and Retrieval System Online (MEDLINE) and Central databases were used for our literature search, which was conducted by three reviewers. We included studies that examined SRS and ipilimumab compared to SRS alone in MBM. Pertinent results were tabulated in a standardized spreadsheet. Newcastle-Ottawa Scale (NOS) Risk of Bias Assessment and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) method for rating evidence quality were used for qualitative analysis. Review Manager was used for statistical analysis. We identified four cohort studies that compared SRS plus ipi versus SRS alone in MBM. As per the GRADE criteria, we found low-quality evidence for survival benefits associated with combined treatment. Meta-analysis confirmed a significant benefit in survival for SRS and ipilimumab (hazard ratio 0.38, 95% confidence interval 0.28 – 0.52, p < 0.01). There were no significant differences between comparison groups for local control, distant brain control, radiation necrosis, or intracranial bleeding. We conclude that low-quality evidence exists for superior overall survival in MBM treated with SRS and ipilimumab compared to SRS without ipilimumab. There is also no increased risk of radiation necrosis and/or intracranial bleeding with combining radiation and immunotherapy in this setting.

Treatment of brain metastasis: current status and future directions

PURPOSE OF REVIEW

The purpose of this review is to highlight the most recent advances in the management of brain metastases.

RECENT FINDINGS

Role of local therapies (surgery and stereotactic radiosurgery), new approaches to minimize cognitive sequelae following whole-brain radiotherapy and advances in targeted therapies have been reviewed.

SUMMARY

The implications for clinical trials and daily practice of the increasing use of stereotactic radiosurgery in multiple brain metastases and upfront targeted agents in asymptomatic brain metastases are discussed.

The radiosurgery fractionation quandary: single fraction or hypofractionation?

Stereotactic radiosurgery (SRS), typically administered in a single session, is widely employed to safely, efficiently, and effectively treat small intracranial lesions. However, for large lesions or those in close proximity to critical structures, it can be difficult to obtain an acceptable balance of tumor control while avoiding damage to normal tissue when single-fraction SRS is utilized. Treating a lesion in 2 to 5 fractions of SRS (termed "hypofractionated SRS" [HF-SRS]) potentially provides the ability to treat a lesion with a total dose of radiation that provides both adequate tumor control and acceptable toxicity. Indeed, studies of HF-SRS in large brain metastases, vestibular schwannomas, meningiomas, and gliomas suggest that a superior balance of tumor control and toxicity is observed compared with single-fraction SRS. Nonetheless, a great deal of effort remains to understand radiobiologic mechanisms for HF-SRS driving the dose-volume response relationship for tumors and normal tissues and to utilize this fundamental knowledge and the results of clinic studies to optimize HF-SRS. In particular, the application of HF-SRS in the setting of immunomodulatory cancer therapies offers special challenges and opportunities.

Postoperative Fractionated Stereotactic Radiosurgery to the Tumor Bed for Surgically Resected Brain Metastases

Introduction

Stereotactic radiosurgery (SRS) is increasingly used as an alternative to whole brain radiotherapy (WBRT) following surgical resection of brain metastases. We analyzed the outcomes of postoperative frameless fractionated stereotactic radiosurgery (fSRS) cases for surgically resected brain metastases at our institution.

Materials and Methods

We performed a retrospective review of 85 patients who underwent fSRS to 87 resection beds from 2006 - 2014 with a median follow-up of 6.4 months. Clinically relevant outcomes were assessed with analysis to determine predictors of these outcomes.

Results

The median target volume was 9.8 cm­³ (1.1 - 43.1 cm­³). The most frequently used fractionation scheme was 3,000 cGy in five fractions. The rates of local control (LC), distant brain failure (DBF), and overall survival (OS) at one-year were 87%, 52%, and 52%, respectively. Five patients (5.9%) experienced Grade >2 toxicity related to fSRS, including seizures (two), symptomatic radionecrosis (two), and potential treatment-related death (one). A multivariable analysis revealed that tumor volume (p < 0.001) and number of fractions (p < 0.001) were associated with LC, while recursive partitioning analysis (RPA) class (p < .0001), tumor volume (p = .0181), and the number of fractions (p = .0181) were associated with OS.

Conclusions

Postoperative fSRS for surgically resected brain metastases is well-tolerated and achieves durable LC. Further studies are needed to determine the optimal dose and fractionation for fSRS as well as to compare outcomes with WBRT.

[Risk of radionecrosis after hypofractionated stereotactic radiotherapy targeting the postoperative resection cavity of brain metastases]

PURPOSE

To investigate the factors that potentially lead to brain radionecrosis after hypofractionated stereotactic radiotherapy targeting the postoperative resection cavity of brain metastases.

METHODS AND MATERIALS

A retrospective analysis conducted in two French centres, was performed in patients treated with trifractionated stereotactic radiotherapy (3×7.7Gy prescribed to the 70% isodose line) for resected brain metastases. Patients with previous whole-brain irradiation were excluded of the analysis. Radionecrosis was diagnosed according to a combination of criteria including clinical, serial imaging or, in some cases, histology. Univariate and multivariate analyses were performed to determine the predictive factors of radionecrosis including clinical and dosimetric variables such as volume of brain receiving a specific dose (V_8Gy-V_22Gy).

RESULTS

One hundred eighty-one patients, with a total of 189 cavities were treated between March 2008 and February 2015. Thirty-five patients (18.5%) developed radionecrosis after a median follow-up of 15 months (range: 3-38 months) after hypofractionated stereotactic radiotherapy. One third of patients with radionecrosis were symptomatic. Multivariate analysis showed that infra-tentorial location was predictive of radionecrosis (hazard ratio [HR]: 2.97; 95% confidence interval [95% CI]: 1.47-6.01; P=0.0025). None V_8Gy-V_22Gy was associated with appearance of radionecrosis, even if V_14Gy trended toward significance (P=0.059).

CONCLUSION

Analysis of patients and treatment variables revealed that infratentorial location of brain metastases was predictive for radionecrosis after hypofractionated stereotactic radiotherapy for postoperative resection cavities.

Outcome Evaluation of Oligometastatic Patients Treated with Surgical Resection Followed by Hypofractionated Stereotactic Radiosurgery (HSRS) on the Tumor Bed, for Single, Large Brain Metastases

Purpose

The aim of this study was to evaluate the benefit of a combined treatment, surgery followed by adjuvant hypofractionated stereotactic radiosurgery (HSRS) on the tumor bed, in oligometastatic patients with single, large brain metastasis (BM).

Methods and Materials

Fom January 2011 to March 2015, 69 patients underwent complete surgical resection followed by HSRS with a total dose of 30Gy in 3 daily fractions. Clinical outcome was evaluated by neurological examination and MRI 2 months after radiotherapy and then every 3 months. Local progression was defined as radiographic increase of the enhancing abnormality in the irradiated volume, and brain distant progression as the presence of new brain metastases or leptomeningeal enhancement outside the irradiated volume. Surgical morbidity and radiation-therapy toxicity, local control (LC), brain distant progression (BDP), and overall survival (OS) were evaluated.

Results

The median preoperative volume and maximum diameter of BM was 18.5cm³ (range 4.1–64.2cm³) and 3.6cm (range 2.1-5-4cm); the median CTV was 29.0cm³ (range 4.1–203.1cm³) and median PTV was 55.2cm³ (range 17.2–282.9cm³). The median follow-up time was 24 months (range 4–33 months). The 1-and 2-year LC in site of treatment was 100%; the median, 1-and 2-year BDP was 11.9 months, 19.6% and 33.0%; the median, 1-and 2-year OS was 24 months (range 4–33 months), 91.3% and 73.0%. No severe postoperative morbidity or radiation therapy toxicity occurred in our series.

Conclusions

Multimodal approach, surgery followed by HSRS, can be an effective treatment option for selected patients with single, large brain metastases from different solid tumors.

HFSRT of the resection cavity in patients with brain metastases

PURPOSE

Aim of this single center, retrospective study was to assess the efficacy and safety of linear accelerator-based hypofractionated stereotactic radiotherapy (HFSRT) to the resection cavity of brain metastases after surgical resection. Local control (LC), locoregional control (LRC = new brain metastases outside of the treatment volume), overall survival (OS) as well as acute and late toxicity were evaluated.

PATIENTS AND METHODS

46 patients with large (> 3 cm) or symptomatic brain metastases were treated with HFSRT. Median resection cavity volume was 14.16 cm(3) (range 1.44-38.68 cm(3)) and median planning target volume (PTV) was 26.19 cm(3) (range 3.45-63.97 cm(3)). Patients were treated with 35 Gy in 7 fractions prescribed to the 95-100 % isodose line in a stereotactic treatment setup. LC and LRC were assessed by follow-up magnetic resonance imaging.

RESULTS

The 1-year LC rate was 88 % and LRC was 48 %; 57% of all patients showed cranial progression after HFSRT (4% local, 44% locoregional, 9% local and locoregional). The median follow-up was 19 months; median OS for the whole cohort was 25 months. Tumor histology and recursive partitioning analysis score were significant predictors for OS. HFSRT was tolerated well without any severe acute side effects > grade 2 according to CTCAE criteria.

CONCLUSION

HFSRT after surgical resection of brain metastases was tolerated well without any severe acute side effects and led to excellent LC and a favorable OS. Since more than half of the patients showed cranial progression after local irradiation of the resection cavity, close patient follow-up is warranted. A prospective evaluation in clinical trials is currently being performed.

Intracranial control after Cyberknife radiosurgery to the resection bed for large brain metastases

Background

Stereotactic radiosurgery (SRS) is an alternative to post-operative whole brain radiation therapy (WBRT) following resection of brain metastases. At our institution, CyberKnife (CK) is considered for local treatment of large cavities ≥2 cm. In this study, we aimed to evaluate patterns of failure and characterize patients best suited to treatment with this approach.

Methods

We retrospectively reviewed 30 patients treated with CK to 33 resection cavities ≥2 cm between 2011 and 2014. Patterns of intracranial failure were analyzed in 26 patients with post-treatment imaging. Survival was estimated by the Kaplan-Meier method and prognostic factors examined with log-rank test and Cox proportional hazards model.

Results

The most frequent histologies were lung (43 %) and breast (20 %). Median treatment volume was 25.1 cm³ (range 4.7–90.9 cm³) and median maximal postoperative cavity diameter was 3.8 cm (range 2.8–6.7). The most common treatment was 30 Gy in 5 fractions prescribed to the 75 % isodose line. Median follow up for the entire cohort was 9.5 months (range 1.0–34.3). Local failure developed in 7 treated cavities (24 %). Neither cavity volume nor CK treatment volume was associated with local failure. Distant brain failure occurred in 20 cases (62 %) at a median of 4.2 months. There were increased rates of distant failure in patients who initially presented with synchronous metastases (p = 0.02). Leptomeningeal carcinomatosis (LMC) developed in 9 cases, (34 %). Salvage WBRT was performed in 5 cases (17 %) at a median of 5.2 months from CK. Median overall survival was 10.1 months from treatment.

Conclusions

This study suggests that adjuvant CK is a reasonable strategy to achieve local control in large resection cavities. Patients with synchronous metastases at the time of CK may be at higher risk for distant brain failure. The majority of cases were spared or delayed WBRT with the use of local CK therapy.

Treatment of brain oligometastases with hypofractionated stereotactic radiotherapy utilising volumetric modulated arc therapy

Stereotactic radiosurgery (SRS) is commonly used to treat brain metastases, particularly in the oligometastatic setting. This study analyses our initial experience in treating oligometastatic brain disease using Volumetric Modulated Arc Therapy (VMAT) to deliver hypofractionated stereotactic radiotherapy (HFSRT). Sixty-one patients were treated with HFSRT with a median dose of 24 Gy (range 22-40 Gy) in a median of three fractions (range 2-10 fractions). With a median follow-up of 23 months, the local control rate was 74 % for the entire cohort. Local control was 87 % for patients who had surgery with no radiological evidence of residual disease followed by HFSRT compared with 69 % in patients treated with HFSRT alone. The overall median time post radiotherapy to local failure was 8.6 months and to extracranial failure was 7.9 months. The mean time to distant brain failure was 9.9 months. Twenty-two patients (36 %) died during the study with median time to death of 4.4 months. Median overall survival (OS) from treatment was 21 months and 12 month OS was 60 %. Our experience with HFSRT using VMAT for oligometastatic brain metastases in the post-operative setting demonstrates comparable local control and survival rates compared with international published data. In the intact brain metastasis setting, local control using the dose levels and delivery in this cohort may be inferior to radio-surgical series. Local control is independent of histology. Careful selection of patients remains critical.

Resection Followed by Involved-Field Fractionated Radiotherapy in the Management of Single Brain Metastasis

Introduction

We expanded upon our previous experience using involved-field fractionated radiotherapy (IFRT) as an alternative to whole brain radiotherapy or stereotactic radiosurgery for patients with surgically resected brain metastases (BM).

Materials and methods

All patients with single BM who underwent surgical resection followed by IFRT at our institution from 2006 to 2013 were evaluated. Local recurrence (LR)-free survival, distant failure (DF)-free survival, and overall survival (OS) were determined. Analyses were performed associating clinical variables with LR and DF. Salvage approaches and toxicity of treatment for each patient were also assessed.

Results

Median follow-up was 19.1 months. Fifty-six patients were treated with a median dose of 40.05 Gy/15 fractions with IFRT to the resection cavity. LR-free survival was 91.4%, DF-free survival was 68.4%, and OS was 77.7% at 12 months. No variables were associated with increased LR; however, melanoma histopathology and infratentorial location were associated with DF on multivariate analysis. LRs were salvaged in 5/8 patients, and DFs were salvaged in 24/29 patients. Two patients developed radionecrosis.

Conclusion

Adjuvant IFRT is feasible and safe for well-selected patients with surgically resected single BM. Acceptable rates of local control and salvage of distal intracranial recurrences continue to be achieved with continued follow-up.

Patterns of Failure after Stereotactic Radiosurgery of the Resection Cavity Following Surgical Removal of Brain Metastases

BACKGROUND

Whole brain radiation treatment (WBRT) is considered standard treatment for BM. However, exposing large volumes of normal brain tissue to irradiation can cause neurotoxicity. This study describes our experience with 100 consecutive patients with brain metastases who were managed with surgical extirpation followed by stereotactic radiosurgery (SRS) to the resection cavity.

METHODS

Patients with 1-3 brain metastases (BM), who underwent resection of 1-2 BM between June 2005 and December 2013, were treated with SRS directed to the tumor cavity and for any synchronous BM. Local and distant treatment failures were determined based on neuroimaging. Kaplan-Meier curves were generated for local and distant failure rates and overall survival.

RESULTS

One hundred and two resection cavities were treated with SRS in 100 consecutive patients. Thirty-two additional synchronous metastases were treated in 27 patients during the same session. The median overall survival was 18.9 months. Local control rate at 1 year was 84%. Longer delays between surgery and SRS were associated with increased risk of local failure (hazard ratio, -1.46; P = 0.02). Distant progression occurred in 44% of the patients at a mean of 8.8 ± 6.6 months after SRS treatment. Ten cases of leptomeningeal spread occurred around the resection cavities (9.8%). Central nervous system failure was not significantly associated with survival. Multivariate Cox regression analysis showed that recursive partitioning analysis and active systemic disease were significantly associated with survival.

CONCLUSION

The strategy described provides acceptable local disease control when compared with WBRT following surgery. This approach can delay and even annul WBRT in the majority of selected BM patients, especially recursive partitioning analysis class I patients. SRS should be scheduled as soon as possible after surgery.