Risk factors for leptomeningeal carcinomatosis in patients with brain metastases who have previously undergone stereotactic radiosurgery

The anatomic basis of leptomeningeal metastasis

Leptomeningeal metastasis (LM), or spread of cancer to the cerebrospinal fluid (CSF)-filled space surrounding the central nervous system, is a fatal complication of cancer. Entry into this space poses an anatomical challenge for cancer cells; movement of cells between the blood and CSF is tightly regulated by the blood-CSF barriers. Anatomical understanding of the leptomeninges provides a roadmap of corridors for cancer entry. This Review describes the anatomy of the leptomeninges and routes of cancer spread to the CSF. Granular understanding of LM by route of entry may inform strategies for novel diagnostic and preventive strategies as well as therapies.

Genomic alterations associated with postoperative nodular leptomeningeal disease after resection of brain metastases

OBJECTIVE

The relationship between brain metastasis resection and risk of nodular leptomeningeal disease (nLMD) is unclear. This study examined genomic alterations found in brain metastases with the aim of identifying alterations associated with postoperative nLMD in the context of clinical and treatment factors.

METHODS

A retrospective, single-center study was conducted on patients who underwent resection of brain metastases between 2014 and 2022 and had clinical and genomic data available. Postoperative nLMD was the primary endpoint of interest. Targeted next-generation sequencing of > 500 oncogenes was performed in brain metastases. Cox proportional hazards analyses were performed to identify clinical features and genomic alterations associated with nLMD.

RESULTS

The cohort comprised 101 patients with tumors originating from multiple cancer types. There were 15 patients with nLMD (14.9% of the cohort) with a median time from surgery to nLMD diagnosis of 8.2 months. Two supervised machine learning algorithms consistently identified CDKN2A/B codeletion and ERBB2 amplification as the top predictors associated with postoperative nLMD across all cancer types. In a multivariate Cox proportional hazards analysis including clinical factors and genomic alterations observed in the cohort, tumor volume (× 10 cm3; HR 1.2, 95% CI 1.01-1.5; p = 0.04), CDKN2A/B codeletion (HR 5.3, 95% CI 1.7-16.9; p = 0.004), and ERBB2 amplification (HR 3.9, 95% CI 1.1-14.4; p = 0.04) were associated with a decreased time to postoperative nLMD.

CONCLUSIONS

In addition to increased resected tumor volume, ERBB2 amplification and CDKN2A/B deletion were independently associated with an increased risk of postoperative nLMD across multiple cancer types. Additional work is needed to determine if targeted therapy decreases this risk in the postoperative setting.

Use of comprehensive genomic profiling for biomarker discovery for the management of non-small cell lung cancer brain metastases

Background

Clinical biomarkers for brain metastases remain elusive. Increased availability of genomic profiling has brought discovery of these biomarkers to the forefront of research interests.

Method

In this single institution retrospective series, 130 patients presenting with brain metastasis secondary to Non-Small Cell Lung Cancer (NSCLC) underwent comprehensive genomic profiling conducted using next generation circulating tumor deoxyribonucleic acid (DNA) (Guardant Health, Redwood City, CA). A total of 77 genetic mutation identified and correlated with nine clinical outcomes using appropriate statistical tests (general linear models, Mantel-Haenzel Chi Square test, and Cox proportional hazard regression models). For each outcome, a genetic signature composite score was created by summing the total genes wherein genes predictive of a clinically unfavorable outcome assigned a positive score, and genes with favorable clinical outcome assigned negative score.

Results

Seventy-two genes appeared in at least one gene signature including: 14 genes had only unfavorable associations, 36 genes had only favorable associations, and 22 genes had mixed effects. Statistically significant associated signatures were found for the clinical endpoints of brain metastasis velocity, time to distant brain failure, lowest radiosurgery dose, extent of extracranial metastatic disease, concurrent diagnosis of brain metastasis and NSCLC, number of brain metastases at diagnosis as well as distant brain failure. Some genes were solely associated with multiple favorable or unfavorable outcomes.

Conclusion

Genetic signatures were derived that showed strong associations with different clinical outcomes in NSCLC brain metastases patients. While these data remain to be validated, they may have prognostic and/or therapeutic impact in the future.

Statement of translation relevance

Using Liquid biopsy in NSCLC brain metastases patients, the genetic signatures identified in this series are associated with multiple clinical outcomes particularly these ones that lead to early or more numerous metastases. These findings can be reverse-translated in laboratory studies to determine if they are part of the genetic pathway leading to brain metastasis formation.

Management Paradigm of Central Nervous System Metastases in NSCLC: An Australian Perspective

Life-prolonging central nervous system active systemic therapies for metastatic NSCLC have increased the complexity of managing brain metastases (BMs). Australian medical oncologists, radiation oncologists, and neurosurgeons discussed the evidence guiding the diverse clinical approaches to the management of BM in NSCLC. The Australian context is broadly applicable to other jurisdictions; therefore, we have documented these discussions as principles with broader applications. Patient management was stratified according to clinical and radiologic factors under two broad classifications of newly diagnosed BMs: symptomatic and asymptomatic. Other important considerations include the number and location of metastases, tumor histotypes, molecular subtype, and treatment purpose. Careful consideration of the pace and burden of symptoms, risk of worsening neurologic function at a short interval, and extracranial disease burden should determine whether central nervous system active systemic therapies are used alone or in combination with local therapies (surgery with or without radiation therapy). Most clinical trial evidence currently focuses on historical treatment options or a single treatment modality rather than the optimal sequencing of multiple modern therapies; therefore, an individualized approach is key in a rapidly changing therapeutic landscape.

Identification of risk factors associated with leptomeningeal disease after resection of brain metastases

OBJECTIVE

Resection of brain metastases (BMs) may be associated with increased risk of leptomeningeal disease (LMD). This study examined rates and predictors of LMD, including imaging subtypes, in patients who underwent resection of a BM followed by postoperative radiation.

METHODS

A retrospective, single-center study was conducted examining overall LMD, classic LMD (cLMD), and nodular LMD (nLMD) risk. Logistic regression, Cox proportional hazards, and random forest analyses were performed to identify risk factors associated with LMD.

RESULTS

Of the 217 patients in the cohort, 47 (21.7%) developed postoperative LMD, with 19 cases (8.8%) of cLMD and 28 cases (12.9%) of nLMD. Six-, 12-, and 24-month LMD-free survival rates were 92.3%, 85.6%, and 71.4%, respectively. Patients with cLMD had worse survival outcomes from the date of LMD diagnosis compared with nLMD (median 2.4 vs 6.9 months, p = 0.02, log-rank test). Cox proportional hazards analysis identified cerebellar/insular/occipital location (hazard ratio [HR] 3.25, 95% confidence interval [CI] 1.73-6.11, p = 0.0003), absence of extracranial disease (HR 2.49, 95% CI 1.27-4.88, p = 0.008), and ventricle contact (HR 2.82, 95% CI 1.5-5.3, p = 0.001) to be associated with postoperative LMD. A predictive model using random forest analysis with an area under the receiver operating characteristic curve of 0.87 in a test cohort identified tumor location, systemic disease status, and tumor volume as the most important factors associated with LMD.

CONCLUSIONS

Tumor location, absence of extracranial disease at the time of surgery, ventricle contact, and increased tumor volume were associated with LMD. Further work is needed to determine whether escalating therapies in patients at risk of LMD prevents disease dissemination.

Single-cell sequencing reveals the landscape of the human brain metastatic microenvironment

Brain metastases is the most common intracranial tumor and account for approximately 20% of all systematic cancer cases. It is a leading cause of death in advanced-stage cancer, resulting in a five-year overall survival rate below 10%. Therefore, there is a critical need to identify effective biomarkers that can support frequent surveillance and promote efficient drug guidance in brain metastasis. Recently, the remarkable breakthroughs in single-cell RNA-sequencing (scRNA-seq) technology have advanced our insights into the tumor microenvironment (TME) at single-cell resolution, which offers the potential to unravel the metastasis-related cellular crosstalk and provides the potential for improving therapeutic effects mediated by multifaceted cellular interactions within TME. In this study, we have applied scRNA-seq and profiled 10,896 cells collected from five brain tumor tissue samples originating from breast and lung cancers. Our analysis reveals the presence of various intratumoral components, including tumor cells, fibroblasts, myeloid cells, stromal cells expressing neural stem cell markers, as well as minor populations of oligodendrocytes and T cells. Interestingly, distinct cellular compositions are observed across different samples, indicating the influence of diverse cellular interactions on the infiltration patterns within the TME. Importantly, we identify tumor-associated fibroblasts in both our in-house dataset and external scRNA-seq datasets. These fibroblasts exhibit high expression of type I collagen genes, dominate cell-cell interactions within the TME via the type I collagen signaling axis, and facilitate the remodeling of the TME to a collagen-I-rich extracellular matrix similar to the original TME at primary sites. Additionally, we observe M1 activation in native microglial cells and infiltrated macrophages, which may contribute to a proinflammatory TME and the upregulation of collagen type I expression in fibroblasts. Furthermore, tumor cell-specific receptors exhibit a significant association with patient survival in both brain metastasis and native glioblastoma cases. Taken together, our comprehensive analyses identify type I collagen-secreting tumor-associated fibroblasts as key mediators in metastatic brain tumors and uncover tumor receptors that are potentially associated with patient survival. These discoveries provide potential biomarkers for effective therapeutic targets and intervention strategies.

What if: A retrospective reconstruction of resection cavity stereotactic radiosurgery to mimic neoadjuvant stereotactic radiosurgery

Introduction

Neoadjuvant stereotactic radiosurgery (NaSRS) of brain metastases has gained importance, but it is not routinely performed. While awaiting the results of prospective studies, we aimed to analyze the changes in the volume of brain metastases irradiated pre- and postoperatively and the resulting dosimetric effects on normal brain tissue (NBT).

Methods

We identified patients treated with SRS at our institution to compare hypothetical preoperative gross tumor and planning target volumes (pre-GTV and pre-PTV) with original postoperative resection cavity volumes (post-GTV and post-PTV) as well as with a standardized-hypothetical PTV with 2.0 mm margin. We used Pearson correlation to assess the association between the GTV and PTV changes with the pre-GTV. A multiple linear regression analysis was established to predict the GTV change. Hypothetical planning for the selected cases was created to assess the volume effect on the NBT exposure. We performed a literature review on NaSRS and searched for ongoing prospective trials.

Results

We included 30 patients in the analysis. The pre-/post-GTV and pre-/post-PTV did not differ significantly. We observed a negative correlation between pre-GTV and GTV-change, which was also a predictor of volume change in the regression analysis, in terms of a larger volume change for a smaller pre-GTV. In total, 62.5% of cases with an enlargement greater than 5.0 cm3 were smaller tumors (pre-GTV < 15.0 cm3), whereas larger tumors greater than 25.0 cm3 showed only a decrease in post-GTV. Hypothetical planning for the selected cases to evaluate the volume effect resulted in a median NBT exposure of only 67.6% (range: 33.2-84.5%) relative to the dose received by the NBT in the postoperative SRS setting. Nine published studies and twenty ongoing studies are listed as an overview.

Conclusion

Patients with smaller brain metastases may have a higher risk of volume increase when irradiated postoperatively. Target volume delineation is of great importance because the PTV directly affects the exposure of NBT, but it is a challenge when contouring resection cavities. Further studies should identify patients at risk of relevant volume increase to be preferably treated with NaSRS in routine practice. Ongoing clinical trials will evaluate additional benefits of NaSRS.

Collagen deposition within brain metastases is associated with leptomeningeal failure after cavity-directed radiosurgery

Background

Leptomeningeal failure (LMF) represents a devastating progression of disease following resection of brain metastases (BrM). We sought to identify a biomarker at time of BrM resection that predicts for LMF using mass spectrometry-based proteomic analysis of resected BrM and to translate this finding with histochemical assays.

Methods

We retrospectively reviewed 39 patients with proteomic data available from resected BrM. We performed an unsupervised analysis with false discovery rate adjustment (FDR) to compare proteomic signature of BrM from patients that developed LMF versus those that did not. Based on proteomic analysis, we applied trichrome stain to a total of 55 patients who specifically underwent resection and adjuvant radiosurgery. We used competing risks regression to assess predictors of LMF.

Results

Of 39 patients with proteomic data, FDR revealed type I collagen-alpha-1 (COL1A1, P = .045) was associated with LMF. The degree of trichrome stain in each block correlated with COL1A1 expression (β = 1.849, P = .001). In a cohort of 55 patients, a higher degree of trichrome staining was associated with an increased hazard of LMF in resected BrM (Hazard Ratio 1.58, 95% CI 1.11-2.26, P = .01).

Conclusion

The degree of trichrome staining correlated with COL1A1 and portended a higher risk of LMF in patients with resected brain metastases treated with adjuvant radiosurgery. Collagen deposition and degree of fibrosis may be able to serve as a biomarker for LMF.

Radiosurgery for Five to Fifteen Brain Metastases: A Single Centre Experience and a Review of the Literature

Purpose

Stereotactic radiosurgery (SRS) is now mainstream for patients with 1-4 brain metastases however the management of patients with 5 or more brain metastases remains controversial. Our aim was to evaluate the clinical outcomes of patients with 5 or more brain metastases and to compare with published series as a benchmarking exercise.

Methods

Patients with 5 or more brain metastases treated with a single isocentre dynamic conformal arc technique on a radiosurgery linac were identified from the institutional database. Endpoints were local control, distant brain failure, leptomeningeal disease and overall survival. Dosimetric data were extracted from the radiosurgery plans. Series reporting outcomes following SRS for multiple brain metastases were identified by a literature search.

Results

36 patients, of whom 35 could be evaluated, received SRS for 5 or more brain metastases between February 2015 and October 2021. 25 patients had 5-9 brain metastases (group 1) and 10 patients had 10-15 brain metastases (group 2). The mean number of brain metastases in group 1 was 6.3 (5-9) and 12.3 (10-15) in group 2. The median cumulative irradiated volume was 4.6 cm³ (1.25-11.01) in group 1 and 7.2 cm³ (2.6-11.1) in group 2. Median follow-up was 12 months. At last follow-up, local control rates per BM were 100% and 99.8% as compared with a median of 87% at 1 year in published series. Distant brain failure was 36% and 50% at a median interval of 5.2 months and 7.4 months after SRS in groups 1 and 2 respectively and brain metastasis velocity at 1 year was similar in both groups (9.7 and 11). 8/25 patients received further SRS and 7/35 patients received whole brain radiotherapy. Median overall survival was 10 months in group 1 and 15.7 months in group 2, which compares well with the 7.5 months derived from the literature. There was one neurological death in group 2, leptomeningeal disease was rare (2/35) and there were no cases of radionecrosis.

Conclusion

With careful patient selection, overall survival following SRS for multiple brain metastases is determined by the course of the extracranial disease. SRS is an efficacious and safe modality that can achieve intracranial disease control and should be offered to patients with 5 or more brain metastases and a constellation of good prognostic factors.

Surgical and anatomic factors predict development of leptomeningeal disease in patients with melanoma brain metastases

BACKGROUND

Leptomeningeal disease (LMD) is a devastating complication of systemic malignancy, of which there is an unclear etiology. The aim of this study is to determine if surgical or anatomic factors can predict LMD in patients with metastatic melanoma.

METHODS

A retrospective chart review was performed of 1162 patients treated at single institution for melanoma brain metastases (MBM). Patients with fewer than 3 months follow-up or lacking appropriate imaging were excluded. Demographic information, surgical, and anatomic data were collected.

RESULTS

Eight hundred and twenty-seven patients were included in the final review. On multivariate analysis for the entire cohort, female gender, dural-based and intraventricular metastasis, and tumor bordering CSF spaces were associated with increased risk of LMD. Surgical resection was not significant for risk of LMD. On multivariate analysis of patients who have undergone surgical resection of a metastatic tumor, dural-based and intraventricular metastasis, ventricular entry during surgery, and metastasis in the infratentorial space were associated with increased risk of LMD. On multivariate analysis of patients who did not undergo surgery, chemotherapy after initial diagnosis and metastasis bordering CSF spaces were associated with increased risk of LMD.

CONCLUSION

In a single-institution cohort of MBM, we found that surgical resection alone did not result in an increased risk of LMD. Anatomical factors such as dural-based and intraventricular metastasis were significant for developing LMD, as well as entry into a CSF space during surgical resection. These data suggest a strong correlation between anatomic location and tumor cell seeding in relation to the development of LMD.

Cerebral metastases

Brain metastases are common and deadly. Over the last 25 years GKNS has been established as an invaluable treatment. It may be used as a primary treatment or after either surgery or WBRT. Patients are assessed using one of a number of available scales. GKNS may be repeated for new metastases and for unresponsive tumors. Prescription doses are usually between 18 and 20Gy. The use of advanced MR techniques to highlight sensitive structures like the hippocampi have extended the efficacy of the treatment. More recently GKNS has been used with different target therapies with improved results. More recently frameless treatments have become more popular in this group of very sick patients. GKNS controls tumors in between 80% and over 95% of cases and may even be used for brainstem tumors.

Brain metastases: An update on the multi-disciplinary approach of clinical management

IMPORTANCE

Brain metastasis (BM) is the most common malignant intracranial neoplasm in adults with over 100,000 new cases annually in the United States and outnumbering primary brain tumors 10:1.

OBSERVATIONS

The incidence of BM in adult cancer patients ranges from 10-40%, and is increasing with improved surveillance, effective systemic therapy, and an aging population. The overall prognosis of cancer patients is largely dependent on the presence or absence of brain metastasis, and therefore, a timely and accurate diagnosis is crucial for improving long-term outcomes, especially in the current era of significantly improved systemic therapy for many common cancers. BM should be suspected in any cancer patient who develops new neurological deficits or behavioral abnormalities. Gadolinium enhanced MRI is the preferred imaging technique and BM must be distinguished from other pathologies. Large, symptomatic lesion(s) in patients with good functional status are best treated with surgery and stereotactic radiosurgery (SRS). Due to neurocognitive side effects and improved overall survival of cancer patients, whole brain radiotherapy (WBRT) is reserved as salvage therapy for patients with multiple lesions or as palliation. Newer approaches including multi-lesion stereotactic surgery, targeted therapy, and immunotherapy are also being investigated to improve outcomes while preserving quality of life.

CONCLUSION

With the significant advancements in the systemic treatment for cancer patients, addressing BM effectively is critical for overall survival. In addition to patient's performance status, therapeutic approach should be based on the type of primary tumor and associated molecular profile as well as the size, number, and location of metastatic lesion(s).

Leptomeningeal disease in neurosurgical brain metastases patients: A systematic review and meta-analysis

Background

Leptomeningeal disease (LMD) is a complication distinguished by progression of metastatic disease into the leptomeninges and subsequent spread via cerebrospinal fluid (CSF). Although treatments for LMD exist, it is considered fatal with a median survival of 2–4 months. A broader overview of the risk factors that increase the brain metastasis (BM) patient's risk of LMD is needed. This meta-analysis aimed to systematically review and quantitatively assess risk factors for LMD after surgical resection for BM.

Methods

A systematic literature search was performed on 7 May 2021. Pooled effect sizes were calculated using a random-effects model for variables reported by three or more studies.

Results

Among 503 studies, thirteen studies met the inclusion criteria with a total surgical sample size of 2105 patients, of which 386 patients developed LMD. The median incidence of LMD across included studies was 16.1%. Eighteen unique risk factors were reported as significantly associated with LMD occurrence, including but not limited to: larger tumor size, infratentorial BM location, proximity of BM to cerebrospinal fluid spaces, ventricle violation during surgery, subtotal or piecemeal resection, and postoperative stereotactic radiosurgery. Pooled results demonstrated that breast cancer as the primary tumor location (HR = 2.73, 95% CI: 2.12–3.52) and multiple BMs (HR = 1.37, 95% CI: 1.18–1.58) were significantly associated with a higher risk of LMD occurrence.

Conclusion

Breast cancer origin and multiple BMs increase the risk of LMD occurrence after neurosurgery. Several other risk factors which might play a role in LMD development were also identified.

Leptomeningeal carcinomatosis and breast cancer: a systematic review of current evidence on diagnosis, treatment and prognosis

Leptomeningeal carcinomatosis (LC) is a rare but challenging manifestation of advanced breast cancer with a severe impact on morbidity and mortality. We performed a systematic review of the evidence published over the last two decades, focusing on recent advances in the diagnostic and therapeutic options of LC. Lobular histology and a triple-negative intrinsic subtype are well-known risk factors for LC. Clinical manifestations are diverse and often aspecific. There is no gold standard for LC diagnosis: MRI and cerebrospinal fluid cytology are the most frequently used modalities despite the low accuracy. Current standard of care involves a multimodal strategy including systemic and intrathecal chemotherapy in combination with brain radiotherapy. Intrathecal chemotherapy has been widely used through the years despite the lack of data from randomized controlled trials and conflicting evidence on patient outcomes. No specific chemotherapeutic agent has shown superiority over others for both intrathecal and systemic treatment. Although endocrine therapy was heuristically considered unable to exert significant control on central nervous system metastatic disease, retrospective data suggest a favourable toxicity profile and even a possible positive impact on survival. In recent years, encouraging data on the use of targeted agents has emerged but further research in this field is required. Palliative treatment in the form of whole brain or stereotactic radiotherapy is associated with improvement in clinical manifestations and quality of life, with no proven impact on survival. The most investigated prognostic factors include performance status, non-triple-negative disease and multimodal treatment. Validation of prognostic scores is necessary to aid clinicians in the identification of patient subgroups that are most likely to benefit from an intensive therapeutic approach.

Successful salvage of recurrent leptomeningeal disease in large cell neuroendocrine lung cancer with stereotactic radiotherapy

A 70-year old male with stage I large cell neuroendocrine carcinoma (LCNEC) of the lung underwent resection of a metachronous 5 cm brain metastasis and received postoperative hypofractionated stereotactic radiotherapy (hfSRT). Five sequential nodular leptomeningeal metastases up to 5.3 cm in diameter were diagnosed on MRI within 10 months and were treated with SRT. Currently the patient has no evidence of intracranial disease 24 months after last irradiation without chemotherapy or whole brain radiotherapy. This is the first report of sustained complete remission of multiple large leptomeningeal metastases achieved with hfSRT, highlighting this brain-sparing approach in selected patients with LCNEC lung cancer.

Stereotactic Radiosurgery for Postoperative Metastatic Surgical Cavities: A Critical Review and International Stereotactic Radiosurgery Society (ISRS) Practice Guidelines

PURPOSE

The purpose of this critical review is to summarize the literature specific to single-fraction stereotactic radiosurgery (SRS) and multiple-fraction stereotactic radiation therapy (SRT) for postoperative brain metastases resection cavities and to present practice recommendations on behalf of the ISRS.

METHODS AND MATERIALS

The Medline and Embase databases were used to apply the Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach to search for manuscripts reporting SRS/SRT outcomes for postoperative brain metastases tumor bed resection cavities with a search end date of July 20, 2018. Prospective studies, consensus guidelines, and retrospective series that included exclusively postoperative brain metastases and had at minimum 100 patients were considered eligible.

RESULTS

The Embase search revealed 157 manuscripts, of which 77 were selected for full-text screening. PubMed yielded 55 manuscripts, of which 23 were selected for full text screening. We deemed 8 retrospective series, 1 phase 2 prospective study, 3 randomized controlled trials, and 1 consensus contouring paper appropriate for inclusion. The data suggest that SRS/SRT to surgical cavities with prescription doses of 30 to 50 Gy equivalent effective dose (EQD) 2₁₀, 50 to 70 Gy EQD2₅, and 70 to 90 EQD2₂ are associated with rates of local control ranging from 60.5% to 91% (median, 80.5%). Randomized data suggest improved local control with single-fraction SRS compared with observation and improved cognitive outcomes compared with whole-brain radiation therapy (WBRT). The toxicity of SRS/SRT in the postoperative setting was limited and is reviewed herein.

CONCLUSIONS

Although randomized data raise concern for poorer local control after resection cavity SRS than WBRT, these findings may be driven by factors such as conservative prescription doses used in the SRS arm. Retrospective studies suggest high rates of local control after single-fraction SRS and hypofractionated SRT for postoperative brain metastases. With a superior neurocognitive profile and no survival disadvantage to withholding WBRT, the ISRS recommends SRS as first-line treatment for eligible postoperative patients. Emerging data suggest that fractionated SRT may provide superior local control compared with single-fraction SRS, in particular, for large tumor cavity volumes/diameters and potentially for patients with a preoperative diameter greater than 2.5 cm.

Predictors of leptomeningeal disease following hypofractionated stereotactic radiotherapy for intact and resected brain metastases

BACKGROUND

The objective was to evaluate the risk and predictors of developing leptomeningeal disease (LMD) in patients with brain metastases treated with 5-fraction hypofractionated stereotactic radiotherapy (HSRT).

METHODS

Patients treated with HSRT for intact brain metastases and/or surgical cavities were reviewed from a prospectively maintained database. Radiographic patterns of LMD were classified as focal classical, diffuse classical, focal nodular, and diffuse nodular.

RESULTS

HSRT was delivered, most commonly 30 Gy in 5 fractions, to 320 intracranial lesions (57% intact and 43% surgical cavities) in 235 patients. The median follow-up was 13.4 months (range, 0.8 to 60 mo). LMD developed in 19% of patients with a 1-year LMD rate of 12%. From the diagnosis of LMD, the median overall survival (OS) was 3.8 months (range, 2-20.8 mo). The most common LMD pattern was diffuse nodular (44%). No difference in OS was observed between LMD patterns (P = 0.203). Multivariable analysis identified surgical cavities at significantly higher risk of LMD compared with intact lesions (odds ratio [OR] = 2.30, 95% CI: 1.24, 4.29, P = 0.008). For cavities, radiosensitive tumors (OR = 2.35, 95% CI: 1.04, 5.35, P = 0.041) predicted for LMD, while, for intact metastases, patients receiving treatment with targeted agents or immunotherapy (TA/I) were at lower risk (OR = 0.178, 95% CI: 0.04, 0.79, P = 0.023).

CONCLUSIONS

Patients who had a brain metastasis resected were at an increased risk of LMD. OS was poor despite treatment of LMD, and no differences in OS based on the pattern of LMD was observed. Treatment with TA/I was observed to be protective against LMD and requires further study.

Treatment Options for Leptomeningeal Metastases of Solid Cancers: Literature Review and Personal Experience

Leptomeningeal metastases (LM) may complicate the clinical course of any solid cancer or hematological malignancy. Diagnosis of such cases requires a multifaceted approach, including careful evaluation of the clinical history, detailed neurological examination, advanced imaging studies, and related laboratory data analysis. Therapeutic options for management of LM have not been standardized yet. Conventional intrathecal chemotherapy with or without involved-field fractionated radiotherapy has only modest efficacy, and the prognosis of most patients remains grim. Therefore, development of new, more aggressive multimodal treatment strategies is definitely needed. Immune checkpoint inhibitors-in particular, molecular targeted therapy-have demonstrated promising results in selected groups of patients. There may be an important role for stereotactic radiosurgery as well. Because organization of prospective randomized multi-institutional trials on treatment of LM of solid cancers may be problematic, practical guidelines for optimal therapeutic strategies in such cases should be established on the basis of integrated results of small-scale prospective and retrospective studies.

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

Simple Summary

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

Abstract

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

Whole-Brain Radiation Therapy Versus Stereotactic Radiosurgery for Cerebral Metastases

Whole-brain radiation therapy (WBRT) was frequently used to treat brain metastases in the past. Stereotactic radiosurgery (SRS) is now generally preferred to WBRT for patients with limited brain metastases. SRS can also be used to treat extensive brain metastases (>10-15 metastases), and clinical trials are currently comparing WBRT with SRS for extensive disease. SRS may allow for an increased risk of radiation necrosis or leptomeningeal disease dissemination after treatment. Preoperative SRS and multifraction radiotherapy decrease the risk of these side effects and may soon become standard of care. Combining SRS with immune checkpoint inhibitors may improve patient outcomes.

Stereotactic Cavity Irradiation or Whole-Brain Radiotherapy Following Brain Metastases Resection-Outcome, Prognostic Factors, and Recurrence Patterns

Introduction: Following the resection of brain metastases (BM), whole-brain radiotherapy (WBRT) is a long-established standard of care. Its position was recently challenged by the less toxic single-session radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT) of the resection cavity, reducing dose exposure of the healthy brain. Patients and Methods: We analyzed 101 patients treated with either SRS/FSRT (n = 50) or WBRT (n = 51) following BM resection over a 5-year period. Propensity score adjustment was done for age, total number of BM, timepoint of BM diagnosis, controlled primary and extracranial metastases. A Cox Proportional Hazards model with univariate and multivariate analysis was fitted for overall survival (OS), local control (LC) and distant brain control (DBC). Results: Median patient age was 61 (interquartile range, IQR: 56-67) years and the most common histology was non-small cell lung cancer, followed by breast cancer. 38% of the patients had additional unresected BM. Twenty-four patients received SRS, 26 patients received FSRT and 51 patients received WBRT. Median OS in the SRS/FSRT subgroup was not reached (IQR NA-16.7 months) vs. 12.6 months (IQR 21.3-4.4) in the WBRT subgroup (hazard ratio, HR 3.3, 95%-CI: [1.5; 7.2] p < 0.002). Twelve-months LC-probability was 94.9% (95%-CI: [88.3; 100.0]) in the SRS subgroup vs. 81.7% (95%-CI: [66.6; 100.0]) in the WBRT subgroup (HR 0.2, 95%-CI: [0.01; 0.9] p = 0.037). Twelve-months DBC-probabilities were 65.0% (95%-CI: [50.8; 83.0]) and 58.8% (95%-CI: [42.9; 80.7]), respectively (HR 1.4, 95%-CI: [0.7; 2.7] p = 0.401). In propensity score-adjusted multivariate analysis, incomplete resection negatively impacted OS (HR 3.9, 95%-CI: [2.0;7.4], p < 0.001) and LC (HR 5.4, 95%-CI: [1.3; 21.9], p = 0.018). Excellent clinical performance (HR 0.4, 95%-CI: [0.2; 0.9], p = 0.030) and better graded prognostic assessment (GPA) score (HR 0.4, 95%-CI: [0.2; 1.0], p = 0.040) were prognostic of superior OS. A higher number of BM was associated with a greater risk of developing new distant BM (HR 5.6, 95%-CI: [1.0; 30.4], p = 0.048). In subgroup analysis, larger cavity volume (HR 1.1, 95%-CI: [1.0; 1.3], p = 0.033) and incomplete resection (HR 12.0, 95%-CI: [1.2; 118.3], p = 0.033) were associated with inferior LC following SRS/FSRT. Conclusion: This is the first propensity score-adjusted direct comparison of SRS/FSRT and WBRT following the resection of BM. Patients receiving SRS/FSRT showed longer OS and LC compared to WBRT. Future analyses will address the optimal choice of safety margin, dose and fractionation for postoperative stereotactic RT of the resection cavity.

Nodular Leptomeningeal Disease-A Distinct Pattern of Recurrence After Postresection Stereotactic Radiosurgery for Brain Metastases: A Multi-institutional Study of Interobserver Reliability

PURPOSE

For brain metastases, surgical resection with postoperative stereotactic radiosurgery is an emerging standard of care. Postoperative cavity stereotactic radiosurgery is associated with a specific, underrecognized pattern of intracranial recurrence, herein termed nodular leptomeningeal disease (nLMD), which is distinct from classical leptomeningeal disease. We hypothesized that there is poor consensus regarding the definition of LMD, and that a formal, self-guided training module will improve interrater reliability (IRR) and validity in diagnosing LMD.

METHODS AND MATERIALS

Twenty-two physicians at 16 institutions, including 15 physicians with central nervous system expertise, completed a 2-phase survey that included magnetic resonance imaging and treatment information for 30 patients. In the "pretraining" phase, physicians labeled cases using 3 patterns of recurrence commonly reported in prospective studies: local recurrence (LR), distant parenchymal recurrence (DR), and LMD. After a self-directed training module, participating physicians completed the "posttraining" phase and relabeled the 30 cases using the 4 following labels: LR, DR, classical leptomeningeal disease, and nLMD.

RESULTS

IRR increased 34% after training (Fleiss' Kappa K = 0.41 to K = 0.55, P < .001). IRR increased most among non-central nervous system specialists (+58%, P < .001). Before training, IRR was lowest for LMD (K = 0.33). After training, IRR increased across all recurrence subgroups and increased most for LMD (+67%). After training, ≥27% of cases initially labeled LR or DR were later recognized as nLMD.

CONCLUSIONS

This study highlights the large degree of inconsistency among clinicians in recognizing nLMD. Our findings demonstrate that a brief self-guided training module distinguishing nLMD can significantly improve IRR across all patterns of recurrence, and particularly in nLMD. To optimize outcomes reporting, prospective trials in brain metastases should incorporate central imaging review and investigator training.

A multi-institutional analysis of presentation and outcomes for leptomeningeal disease recurrence after surgical resection and radiosurgery for brain metastases

BACKGROUND

Radiographic leptomeningeal disease (LMD) develops in up to 30% of patients following postoperative stereotactic radiosurgery (SRS) for brain metastases. However, the clinical relevancy of this finding and outcomes after various salvage treatments are not known.

METHODS

Patients with brain metastases, of which 1 was resected and treated with adjunctive SRS, and who subsequently developed LMD were combined from 7 tertiary care centers. LMD pattern was categorized as nodular (nLMD) or classical ("sugarcoating," cLMD).

RESULTS

The study cohort was 147 patients. Most patients (60%) were symptomatic at LMD presentation, with cLMD more likely to be symptomatic than nLMD (71% vs. 51%, P = 0.01). Salvage therapy was whole brain radiotherapy (WBRT) alone (47%), SRS (27%), craniospinal radiotherapy (RT) (10%), and other (16%), with 58% receiving a WBRT-containing regimen. WBRT was associated with lower second LMD recurrence compared with focal RT (40% vs 68%, P = 0.02). Patients with nLMD had longer median overall survival (OS) than those with cLMD (8.2 vs 3.3 mo, P < 0.001). On multivariable analysis for OS, pattern of initial LMD (nodular vs classical) was significant, but type of salvage RT (WBRT vs focal) was not.

CONCLUSIONS

Nodular LMD is a distinct pattern of LMD associated with postoperative SRS that is less likely to be symptomatic and has better OS outcomes than classical "sugarcoating" LMD. Although focal RT demonstrated increased second LMD recurrence compared with WBRT, there was no associated OS detriment. Focal cranial RT for nLMD recurrence after surgery and SRS for brain metastases may be a reasonable alternative to WBRT.

Pre-Operative Versus Post-Operative Radiosurgery of Brain Metastases-Volumetric and Dosimetric Impact of Treatment Sequence and Margin Concept

BACKGROUND

Pre-operative radiosurgery (SRS) preceding the resection of brain metastases promises to circumvent limitations of post-operative cavity SRS. It minimizes uncertainties regarding delineation and safety margins and could reduce dose exposure of the healthy brain (HB).

METHODS

We performed a systematic treatment plan comparison on 24 patients who received post-operative radiosurgery of the resection cavity at our institution. Comparative treatment plans were calculated for hypofractionated stereotactic radiotherapy (7 × 5 Gray (Gy)) in a hypothetical pre-operative (pre-op) and two post-operative scenarios, either with (extended field, post-op-E) or without the surgical tract (involved field, post-op-I). Detailed volumetric comparison of the resulting target volumes was performed, as well as dosimetric comparison focusing on targets and the HB.

RESULTS

The resection cavity was significantly smaller and different in morphology from the pre-operative lesion, yielding a low Dice Similarity Coefficient (DSC) of 53% (p = 0.019). Post-op-I and post-op-E targets showed high similarity (DSC = 93%), and including the surgical tract moderately enlarged resulting median target size (18.58 ccm vs. 22.89 ccm, p < 0.001). Dosimetric analysis favored the pre-operative treatment setting since it significantly decreased relevant dose exposure of the HB (Median volume receiving 28 Gy: 6.79 vs. 10.79 for pre-op vs. post-op-E, p < 0.001). Dosimetrically, pre-operative SRS is a promising alternative to post-operative cavity irradiation that could furthermore offer practical benefits regarding delineation and treatment planning. Comparative trials are required to evaluate potential clinical advantages of this approach.

Immunotherapy is associated with improved survival and decreased neurologic death after SRS for brain metastases from lung and melanoma primaries

Background

The effect of immunotherapy on brain metastasis patients remains incompletely understood. Our goal was to evaluate its effect on survival, neurologic death, and patterns of failure after stereotactic radiosurgery (SRS) without prior whole-brain radiation therapy (WBRT) in patients with lung and melanoma primaries metastatic to the brain.

Methods

We performed a retrospective analysis of 271 consecutive lung or melanoma patients treated with upfront SRS for brain metastases between 2013 and 2018. Of these patients, 101 (37%) received immunotherapy and 170 (63%) did not. Forty-three percent were treated with nivolumab. Thirty-seven percent were treated with pembrolizumab. Fifteen percent were treated with ipilimumab. One percent were treated with a combination of nivolumab and ipilimumab. One percent were treated with atezolizumab. Three percent were treated with another immunotherapy regimen. Survival was estimated by the Kaplan-Meier method and cumulative incidences of neurologic death, and local and distant brain failure were estimated using death as a competing risk.

Results

The median overall survival (OS) of patients treated with immunotherapy vs without was 15.9 (95% CI: 13.3 to 24.8) vs 6.1 (95% CI: 5.1 to 8.8) months (P < .01). The 1-year cumulative incidence of neurologic death was 9% in patients treated with immunotherapy vs 23% in those treated without (P = .01), while nonneurologic death was not significantly different (29% vs 41%, P = .51). Median brain metastasis velocity (BMV) did not differ between groups, and rates of salvage SRS and WBRT were similar.

Conclusions

The use of immunotherapy in patients with lung cancer or melanoma metastatic to the brain treated with SRS is associated with improved OS and decreased incidence of neurologic death.

Surgical resection and postoperative radiosurgery versus staged radiosurgery for large brain metastases

PURPOSE

The purpose of this study was to retrospectively evaluate the new treatment paradigm of staged stereotactic radiosurgery (SRS) for the treatment of large brain metastases (BM) compared to the standard of surgical resection followed by SRS.

METHODS

We evaluated 78 patients with large BM treated 2012-2017 with surgical resection and postoperative SRS (surgery + SRS) or staged SRS separated by 1 month. Overall survival (OS) was estimated using the Kaplan Meier method and compared across groups using the log-rank test. Cumulative incidence of neurologic death and local and distant brain failure (LF, DBF) were estimated using competing risk methodology.

RESULTS

Forty patients were treated with surgery + SRS and 38 patients were treated with staged SRS. Median follow-up was 23.2 months (95% CI 20.5-39.3). Median OS was 13.2 months for staged SRS compared to surgery + SRS 9.7 months (p = 0.53). Cumulative incidence of neurologic death at 1 year was 23% after surgery + SRS, 27% after staged SRS (p = 0.69); cumulative incidence of LF at 1 year was 6% and 8% (p = 0.65) and 1-year DBF was 59% and 21% (p ≤ 0.01). Overall rates of leptomeningeal failure and radiation necrosis were similar between the groups (p = 0.63 and p = 1.0).

CONCLUSIONS

Though surgery and postoperative SRS is the standard, staged SRS represents an attractive treatment paradigm for treating large BM without sacrificing LC or survival, and potentially decreases DBF. Prospective studies are needed to validate these findings.

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.

Comparing Preoperative With Postoperative Stereotactic Radiosurgery for Resectable Brain Metastases: A Multi-institutional Analysis

BACKGROUND

Stereotactic radiosurgery (SRS) is an increasingly common modality used with surgery for resectable brain metastases (BM).

OBJECTIVE

To present a multi-institutional retrospective comparison of outcomes and toxicities of preoperative SRS (Pre-SRS) and postoperative SRS (Post-SRS).

METHODS

We reviewed the records of patients who underwent resection of BM and either Pre-SRS or Post-SRS alone between 2005 and 2013 at 2 institutions. Pre-SRS used a dose-reduction strategy based on tumor size, with planned resection within 48 hours. Cumulative incidence with competing risks was used to determine estimated rates.

RESULTS

A total of 180 patients underwent surgical resection for 189 BM: 66 (36.7%) underwent Pre-SRS and 114 (63.3%) underwent Post-SRS. Baseline patient characteristics were balanced except for higher rates of performance status 0 (62.1% vs 28.9%, P < .001) and primary breast cancer (27.2% vs 10.5%, P = .010) for Pre-SRS. Pre-SRS had lower median planning target volume margin (0 mm vs 2 mm) and peripheral dose (14.5 Gy vs 18 Gy), but similar gross tumor volume (8.3 mL vs 9.2 mL, P = .85). The median imaging follow-up period was 24.6 months for alive patients. Multivariable analyses revealed no difference between groups for overall survival (P = .1), local recurrence (P = .24), and distant brain recurrence (P = .75). Post-SRS was associated with significantly higher rates of leptomeningeal disease (2 years: 16.6% vs 3.2%, P = .010) and symptomatic radiation necrosis (2 years: 16.4% vs 4.9%, P = .010).

CONCLUSION

Pre-SRS and Post-SRS for resected BM provide similarly favorable rates of local recurrence, distant brain recurrence, and overall survival, but with significantly lower rates of symptomatic radiation necrosis and leptomeningeal disease in the Pre-SRS cohort. A prospective clinical trial comparing these treatment approaches is warranted.

ABBREVIATIONS

BM, brain metastasesCI, confidence intervalCTV, clinical target volumeDBR, distant brain recurrenceGTV, gross tumor volumeLC, local controlLMD, leptomeningeal diseaseLR, local recurrenceMVA, multivariable analysisOS, overall survivalPost-SRS, postoperative stereotactic radiosurgeryPre-SRS, preoperative stereotactic radiosurgeryPTV, planning target volumeRN, radiation necrosisSRN, symptomatic radiation necrosisSRS, stereotactic radiosurgeryWBRT, whole-brain radiation therapy.

Leptomeningeal failure in patients with breast cancer receiving stereotactic radiosurgery for brain metastases

PURPOSE

Prior studies suggest a high incidence of leptomeningeal failure (LMF) in breast cancer metastatic to brain. This study examines breast cancer-specific variables affecting development of LMF and survival after Gamma-Knife Radiosurgery (GKS).

METHODS

Between 2000-2010, 149 (breast) and 658 other-histology patients were treated with GKS. Hormone/HER2, age, local/distant brain failure, prior craniotomy, and prior whole-brain radiotherapy (WBRT) were assessed. Median follow-up was 54months (range, 0-106). Serial MRI determined local and distant-brain failure and LMF. Statistical analysis with categorical/continuous data comparisons were done with Fisher's-exact, Wilcoxon rank-sum, log-rank tests, and Cox-Proportional Hazard models.

RESULTS

Of 149 patients, 21 (14%) developed LMF (median time of 11.9months). None of the following predicted for LMF: Her2-status (HR=0.49, p=0.16), hormone-receptor status (HR=1.15, p=0.79), prior craniotomy (HR=1.58, p=0.42), prior WBRT (HR=1.36, p=0.55). Non-significant factors between patients that did (n=21) and did not (n=106) develop LMF included neurologic death (p=0.34) and median survival (8.6 vs 14.2months, respectively). Breast patients who had distant-failure after GKS (65/149; 43.6%) were more likely to later develop LMF (HR 4.2, p=0.005); including 15/65 (23%) patients who had distant-failure and developed LMF. Median time-to-death for patients experiencing LMF was 6.1months (IQR 3.4-7.8) from onset of LMF. Median survival from LMF to death was much longer in breast (6.1months) than in other (1.7months) histologies CONCLUSION: Breast cancer patients had a longer survival after diagnosis of LMF versus other histologies. Neither ER/PR/HER2 status, nor prior surgery or prior WBRT predicted for development of LMF in breast patients.

Methods and results of local treatment of brain metastases in patients with breast cancer

This article presents methods and results of surgical treatment and radiation therapy of brain metastases in breast cancer patients (brain metastases from breast cancer BMF-BC). Based on the literature data, it was shown that patients with single BMF-BC, aged less than 65 years, with Karnofsky score (KPS) of 70 or more and with cured or controlled extracranial disease are the best candidates to surgical treatment. Irrespective of the extracranial disease control status, there are indications for surgery in patients with symptomatic mass effect (tumour diameter larger than 3 cm) and patients with obstructive hydrocephalus from their BMF-BC. Stereotactic radiosurgery (SRS) has some advantages over surgery, with similar effectiveness: it may be used in the treatment of lesions inaccessible to surgery, the number of lesion is not a limiting factor if each lesion is small (< 3) and adequate doses can be delivered, it is not contraindicated in patients with active extracranial disease, it does not interfere with ongoing systemic treatment, and it does not require general anaesthesia or hospitalisation. A disadvantage of SRS, as compared to whole brain radiotherapy (WBRT), in patients with BMF-BC is the possibility of subsequent development of new lesion in the non-irradiated field. Thus the majority of the BMF-BC patients are not good candidates to surgery or SRS; WBRT alone or combined with a systemic treatment still plays a major role in the treatment of these patients.

Gamma Knife radiosurgery for brain metastases from gastrointestinal primary

INTRODUCTION

In this study, we assessed clinical outcomes of patients with brain metastases from a gastrointestinal (GI) primary cancer and patterns of failure after stereotactic radiosurgery including failure within the radiosurgical volume, distant failure and leptomeningeal failure (LMF). We also assessed other factors associated with the patients' neurologic and extraneuraxial disease that may affect clinical outcomes.

METHODS

We reviewed our institutional series of 62 consecutive patients with brain metastases treated with stereotactic radiosurgery, which included 17 patients with oesophageal, 44 patients with colorectal and one patient with anal canal primary. The median marginal dose to the radiosurgery volume was 17 Gy (range 10-24 Gy). Thirteen patients were treated with whole-brain radiotherapy (WBRT) prior to GKS.

RESULTS

The median dose delivered to the margin of the tumour was 17 Gy (range: 10-24 Gy). The median largest tumour diameter was 2.7 cm (range: 0.60-6.1 cm). The median overall survival (OS) was 7.1 months with a median follow-up of 6.1 months and a range of 0-31.7 months. Freedom from local failure was 86.5% and 62.2% at 6 and 12 months respectively. Freedom from distant failure was 73.2% and 42.2% at 6 and 12 months, respectively, and 40% of patients died of neurologic death. LMF occurred in seven patients, all of whom had colorectal primaries. Multivariate analysis revealed that craniotomy for resection of brain metastasis (HR = 2.63, P < 0.02), an absence of extracranial disease (HR = 2.28, P < 0.03), and prolonged time to distant brain failure (HR = 2.85, P < 0.01) predicted for improved survival.

CONCLUSIONS

Colorectal cancer metastases tend to have a higher rate of leptomeningeal failure than other types of GI cancer metastases. Radiosurgical management of brain metastases from GI primary represents an acceptable management option. Neurologic death remains problematic.

Comparing pre-operative stereotactic radiosurgery (SRS) to post-operative whole brain radiation therapy (WBRT) for resectable brain metastases: a multi-institutional analysis

Pre-operative stereotactic radiosurgery (pre-SRS) has been shown as a viable treatment option for resectable brain metastases (BM). The aim of this study is to compare oncologic outcomes and toxicities for pre-SRS and post-operative WBRT (post-WBRT) for resectable BM. We reviewed records of consecutive patients who underwent resection of BM and either pre-SRS or post-WBRT between 2005 and 2013 at two institutions. Overall survival (OS) was calculated using the Kaplan-Meier method. Cumulative incidence was used for intracranial outcomes. Multivariate analysis (MVA) was performed using the Cox and Fine and Gray models, respectively. Overall, 102 patients underwent surgical resection of BM; 66 patients with 71 lesions received pre-SRS while 36 patients with 42 cavities received post-WBRT. Baseline characteristics were similar except for the pre-SRS cohort having more single lesions (65.2% vs. 38.9%, p = 0.001) and smaller median lesion volume (8.3 cc vs. 15.3 cc, p = 0.006). 1-year OS was similar between cohorts (58% vs. 56%, respectively) (p = 0.43). Intracranial outcomes were also similar (2-year outcomes, pre-SRS vs. post-WBRT): local recurrence: 24.5% vs. 25% (p = 0.81), distant brain failure (DBF): 53.2% vs. 45% (p = 0.66), and leptomeningeal disease (LMD) recurrence: 3.5% vs. 9.0% (p = 0.66). On MVA, radiation cohort was not independently associated with OS or any intracranial outcome. Crude rates of symptomatic radiation necrosis were 5.6 and 0%, respectively. OS and intracranial outcomes were similar for patients treated with pre-SRS or post-WBRT for resected BM. Pre-SRS is a viable alternative to post-WBRT for resected BM. Further confirmatory studies with neuro-cognitive outcomes comparing these two treatment paradigms are needed.

Effects of Postoperative Radiotherapy on Leptomeningeal Carcinomatosis or Dural Metastasis after Resection of Brain Metastases in Breast Cancer Patients

Purpose

In this retrospective study, we compared the incidence of leptomeningeal carcinomatosis or dural metastasis (LMCDM) in patients who received whole brain radiotherapy (WBRT), partial radiotherapy (PRT), or no radiotherapy (RT) following resection of brain metastases from breast cancer.

Materials and Methods

Fifty-one patients with breast cancer underwent surgical resection for newly diagnosed brain metastases in two institutions between March 2001 and March 2015. Among these, 34 received postoperative WBRT (n=24) or PRT (n=10) and 17 did not.

Results

With a median follow-up of 12.4 months (range, 2.3 to 83.6 months), 22/51 patients developed LMCDM at a median of 8.6 months (range, 4.8 to 51.2 months) after surgery. The 18-months LMCDM-free survival (LMCDM-FS) rates were 77.5%, 30.0%, and 13.6%, in the WBRT, PRT, and no RT groups, respectively (p=0.013). The presence of a tumor adjacent to cerebrospinal fluid flow and no systemic treatment after treatment for brain metastases were also associated with poor LMCDM-FS rate. Multivariate analysis showed that WBRT compared to PRT (p=0.009) and systemic treatment (p < 0.001) were independently associated with reduced incidence of LMCDM.

Conclusion

WBRT improved LMCDM-FS rate after resection of brain metastases compared to PRT in breast cancer patients.

Leukoencephalopathy in long term brain metastases survivors treated with radiosurgery

Brain metastases (BM) develop in 10-30 % of patients. Stereotactic radiosurgery (SRS) was shown to improve local control, and performance status, in certain cohorts of brain metastasis patients. The cumulative neurocognitive effect of numerous SRS sessions remains unknown. Leukoencephalopathy is significant diffuse white matter changes and it usually implies a neurocognitive decline. We report patients with BM who survived >2 years after SRS. Clinical and treatment parameters were analyzed for development of leukoencephalopathy. Multiple parameters as well as leukoencephalopathy grade changes were recorded. The median clinical and radiological follow-up was 42 and 41 months (range 24–115 and 24–115) respectively. The cohort included 92 patients and 704 lesions. The most common malignancies were non-small cell lung carcinoma (44.5 % n = 41), breast adenocarcinoma (23.9 %, n = 22) and melanoma (16.3 %,n = 15). 27.6 % (n = 26) of patients underwent adjuvant WBRT. At last follow up, local tumor control was achieved in 76.3 % (n = 61) of patients and 71.8 % (n = 461) of lesions. Overall prevalence of leukoencephalopathy was 42, 60, 73 and 84 % at 1, 2, 3, and 4 years after SRS. Moderate-severe leukoencephalopathy development was related to an integral dose to skull >3 Joules (p = 0.012) at any radiosurgical treatment and prior WBRT (p<0.042). Leukoencephalopathy incidence was consistently higher in the WBRT + SRS group at each following year of survival from initial SRS. Long-term BM survivors treated with SRS are at progressive risk for developing leukoencephalopathy.Those with a higher BM burden, higher integral SRS dose to the skull, and treatment with WBRT are at increased risk of leukoencephalopathy.

Repeat stereotactic radiosurgery as salvage therapy for locally recurrent brain metastases previously treated with radiosurgery

OBJECTIVE There are a variety of salvage options available for patients with brain metastases who experience local failure after stereotactic radiosurgery (SRS). These options include resection, whole-brain radiation therapy, laser thermoablation, and repeat SRS. There is little data on the safety and efficacy of repeat SRS following local failure of a prior radiosurgical procedure. This study evaluates the clinical outcomes and dosimetric characteristics of patients who experienced tumor recurrence and were subsequently treated with repeat SRS. METHODS Between 2002 and 2015, 32 patients were treated with repeat SRS for local recurrence of ≥ 1 brain metastasis following initial SRS treatment. The Kaplan-Meier method was used to estimate time-to-event outcomes including overall survival (OS), local failure, and radiation necrosis. Cox proportional hazards analysis was performed for predictor variables of interest for each outcome. Composite dose-volume histograms were constructed for each reirradiated lesion, and these were then used to develop a predictive dosimetric model for radiation necrosis. RESULTS Forty-six lesions in 32 patients were re-treated with a second course of SRS after local failure. A median dose of 20 Gy (range 14-22 Gy) was delivered to the tumor margin at the time of repeat SRS. Local control at 1 year was 79% (95% CI 67%-94%). Estimated 1-year OS was 70% (95% CI 55%-88%). Twelve patients had died at the most recent follow-up, with 8/12 patients experiencing neurological death (as described in Patchell et al.). Eleven of 46 (24%) lesions in 11 separate patients treated with repeat SRS were associated with symptomatic radiation necrosis. Freedom from radiation necrosis at 1 year was 71% (95% CI 57%-88%). Analysis of dosimetric data revealed that the volume of a lesion receiving 40 Gy (V_40Gy) was the most predictive factor for the development of radiation necrosis (p = 0.003). The following V_40Gy thresholds were associated with 10%, 20%, and 50% probabilities of radiation necrosis, respectively: 0.28 cm³ (95% CI 3%-28%), 0.76 cm³ (95% CI 9%-39%), 1.60 cm³ (95% CI 26%-74%). CONCLUSIONS Repeat SRS appears to be an effective salvage option for patients with brain metastases experiencing local failure following initial SRS treatment. This series demonstrates durable local control and, although rates of radiation necrosis are significant, repeat SRS may be indicated for select cases of local disease recurrence. Because the V_40Gy is predictive of radiation necrosis, limiting this value during treatment planning may allow for a reduction in radiation necrosis rates.

Whole brain radiotherapy in management of non-small-cell lung carcinoma associated leptomeningeal carcinomatosis: evaluation of prognostic factors

To assess the efficacy of whole-brain radiotherapy (WBRT) and prognostic factors in leptomeningeal carcinomatosis (LMC) of non-small-cell lung cancer (NSCLC) patients. WBRT records of 51 LMC patients confined to brain were reviewed. Eligible patients had squamous-cell carcinoma (SCC) or adenocarcinoma, and Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0-3. The WBRT was either 20 or 30 Gray. The primary and secondary objectives were to determine overall survival (OS) and prognostic factors for improved treatment response, respectively. Median age was 53 years (range 39-68), 58.8 % had SCC, 74.5 % had ECOG PS 1-2, and 70.6 % had LMC accompanied by parenchymal brain metastases (BM). The median follow-up was 4.1 months (range 0.7-14.4); all patients died due to disease progression. Median OS was 3.9 months (95 % CI 3.3-4.5) with 6 and 12 month estimates of 19.6 and 5.9 %, respectively. Evaluation of prognostic factors revealed that patients with ECOG 1, longer time to LMC (TT-LMC) from NSCLC diagnosis (>11.3 months), and absence of parenchymal BM had significantly superior OS than those patients with ECOG 2 (p = 0.01) or 3 (p < 0.001), TT-LMC < 11.3 months (p = 0.001), and parenchymal BM (p = 0.012). Median OS of 3.9 months after WBRT appeared to confirm the poor prognosis of LMC. WBRT might be most effective for patients with favorable PS, longer TT-LMC, and no accompanying BM. Therefore, we identified ECOG PS 1, TT-LMC > 11.3 months, and no BM as independent prognosticators for better response to WBRT in NSCLC patients with LMC.

[Carcinomatous meningitis: The radiation therapist's point of view]

Carcinomatous meningitis complicates 5 to 10% of cancers, essentially with breast cancers, lung cancers and melanomas. The incidence probably increased because of therapeutic advances in oncology. Treatment is based on external beam radiotherapy, systemic treatment, intrathecal chemotherapy and supportive care. The aim of this work was to review data on external radiation therapy and carcinomatous meningitis. There are few evidences on the subject, but it is a major topic of interest. A whole brain radiation therapy is indicated in case of brain metastases or clinical encephalitis. Focal radiation therapy is recommended on symptomatic, bulky or obstructive sites. The dose depends on performance status (20 to 40 Gy in five to 20 fractions), volume to treat and available techniques (classic fractionation or hypofractionation via stereotactic radiosurgery). The objective of radiation therapy is to improve quality of life. Association with systemic therapy improves overall survival. Administration of sequential intrathecal chemotherapy may also improve overall survival, but induces more toxicity. The use of new radiotherapy techniques and development of radiosensitizing molecules in patients with good performance status could improve survival in this frequent complication of cancer.

Leptomeningeal disease following stereotactic radiosurgery for brain metastases from breast cancer

Leptomeningeal disease (LMD) is a highly aggressive and usually rapidly fatal condition. The purpose of this study is to identify clinical factors that can serve to predict for LMD at the time of stereotactic radiosurgery (SRS) for brain metastases from breast carcinoma. We conducted a retrospective review of patients with brain metastases from breast cancer treated with SRS from 1995 to 2014 at our institution. Clinical, radiographic, and dosimetric data were collected. LMD was diagnosed by cerebrospinal fluid (CSF) cytology or MRI demonstrating CSF seeding. Comparative statistical analyses were conducted using Cox proportional hazards regression, binary logistic regression, and/or log-rank test. 126 patients met inclusion criteria. Eighteen patients (14 %) developed LMD following SRS. From the time of SRS, the actuarial rate of LMD at 12 months from diagnosis of brain metastasis was 9 % (11 patients). Active disease in the chest at the time of SRS was associated with development of LMD (p = 0.038). Factors including receptor status, tumor size, number of intra-axial tumors, cystic tumor morphology, prior WBRT, active bone metastases, and active liver metastases were not significantly associated with the development of LMD. In patients with brain metastasis from breast cancer that undergo SRS, there is a relatively low rate of LMD. We found that while tumor hormonal status, bone metastases, and hepatic metastases were not associated with the development of LMD, active lung metastases at SRS was associated with LMD. Further research may help to delineate a causative relationship between metastatic lung disease and LMD.