Management of Brain Metastases

Bevacizumab reduces cerebral radiation necrosis due to stereotactic radiotherapy in non-small cell lung cancer patients with brain metastases: an inverse probability of treatment weighting analysis

Background

Cerebral radiation necrosis (RN), a severe complication of stereotactic radiotherapy (SRT), has been shown to significantly decrease patient survival time and quality of life. The purpose of this study was to analyze whether bevacizumab can prevent or reduce the occurrence of SRT-induced cerebral RN in non-small cell lung cancer (NSCLC) patients with brain metastases.

Materials and methods

We retrospectively reviewed the clinical records of NSCLC patients with brain metastases from March 2013 to June 2023 who were treated with SRT. Patients were divided into two groups: those in the bevacizumab group received SRT with four cycles of bevacizumab, and patients in the control group received SRT only. Inverse probability of treatment weighting (IPTW) was performed based on a multinomial propensity score model to balance the baseline characteristics. The chi-square test was used. A Cox model was used to evaluate overall survival (OS).

Results

A total of 80 patients were enrolled, namely, 28 patients in the bevacizumab group and 52 patients in the control group. The possibility of developing cerebral RN and/or symptomatic edema (RN/SE) was significantly decreased in patients treated with bevacizumab compared to those who did not receive bevacizumab before IPTW (p=0.036) and after IPTW (p=0.015) according to chi-square analysis. The IPTW-adjusted median OS was 47.7 months (95% CI 27.4-80.8) for patients in the bevacizumab group and 44.1 months (95% CI 36.7-68.0) (p=0.364) for patients in the control group.

Conclusion

The application of bevacizumab concurrent with SRT may prevent or reduce the occurrence of cerebral RN in NSCLC patients with brain metastases.

Management of Brain Metastases: A Review of Novel Therapies

Brain metastases (BMs) represent the most common intracranial tumors in adults, and most commonly originate from lung, followed by breast, melanoma, kidney, and colorectal cancer. Management of BM is individualized based on the size and number of brain metastases, the extent of extracranial disease, the primary tumor subtype, neurological symptoms, and prior lines of therapy. Until recently, treatment strategies were limited to local therapies, like surgical resection and radiotherapy, the latter in the form of whole-brain radiotherapy or stereotactic radiosurgery. The next generation of local strategies includes laser interstitial thermal therapy, magnetic hyperthermic therapy, post-resection brachytherapy, and focused ultrasound. New targeted therapies and immunotherapies with documented intracranial activity have transformed clinical outcomes. Novel systemic therapies with intracranial utility include new anaplastic lymphoma kinase inhibitors like brigatinib and ensartinib; selective "rearranged during transfection" inhibitors like selpercatinib and pralsetinib; B-raf proto-oncogene inhibitors like encorafenib and vemurafenib; Kirsten rat sarcoma viral oncogene inhibitors like sotorasib and adagrasib; ROS1 gene rearrangement (ROS1) inhibitors, anti-neurotrophic tyrosine receptor kinase agents like larotrectinib and entrectinib; anti-human epidermal growth factor receptor 2/epidermal growth factor receptor exon 20 agent like poziotinib; and antibody-drug conjugates like trastuzumab-emtansine and trastuzumab-deruxtecan. This review highlights the modern multidisciplinary management of BM, emphasizing the integration of systemic and local therapies.

Survival Outcomes and Predictors for Recurrence of Surgically Treated Brain Metastasis From Non-Small Cell Lung Cancer

Background

There are numerous factors to consider in deciding whether to undergo surgical treatment for brain metastasis from lung cancer. Herein, we aimed to analyze the survival outcome and predictors of recurrence of surgically treated brain metastasis from non-small cell lung cancer (NSCLC).

Methods

A total of 197 patients with brain metastasis from NSCLC who underwent microsurgery were included in this study.

Results

A total of 114 (57.9%) male and 83 (42.1%) female patients with a median age of 59 years (range, 27–79) was included in this study. The median follow-up period was 22.7 (range, 1–126) months. The 1-year and 2-year overall survival (OS) rates of patients with brain metastasis secondary to NSCLC were 59% and 43%, respectively. The 6-month and 1-year progression-free survival (PFS) rates of local recurrence were 80% and 73%, respectively, whereas those of distant recurrence were 84% and 63%, respectively. En-bloc resection of tumor resulted in better PFS for local recurrence (1-year PFS: 79% vs. 62%, p=0.02). Ventricular opening and direct contact between the tumor and the subarachnoid space were not associated with distal recurrence and leptomeningeal seeding. The difference in PFS of local recurrence according to adjuvant resection bed irradiation was not significant. Moreover, postoperative whole-brain irradiation did not show a significant difference in PFS of distant recurrence. In multivariate analysis, only en-bloc resection was a favorable prognostic factor for local recurrence. Contrastingly, multiple metastasis was a poor prognostic factor for distant recurrence.

Conclusion

En-bloc resection may reduce local recurrence after surgical resection. Ventricular opening and contact between the tumor and subarachnoid space did not show a statistically significant result for distant recurrence and leptomeningeal seeding. Multiple metastasis was only meaningful factor for distant recurrence.

Quantitative MR Perfusion for the Differentiation of Recurrence and Radionecrosis in Hypoperfusion and Hyperperfusion Brain Metastases After Gamma Knife Radiosurgery

Objectives

Dynamic susceptibility contrast perfusion weighted imaging (DSC-PWI) plays an important role in the differential diagnosis between radionecrosis and recurrence of brain metastases (BMs) after gamma knife radiosurgery (GKRS). While the perfusion condition of preliminary hyperperfusion and hypoperfusion BMs when recur has not been studied, as well the separating performance of quantitative DSC-PWI in both kinds of BMs.

Methods

From February 2017 to October 2019, quantitative DSC-PWI was performed in patients with untreated BMs in this observational study. Patients were assigned to hyperperfusion and hypoperfusion group according the quantitative cerebral blood volume (qCBV). During follow-up after GKRS, patients with a diagnostic pitfall of radionecrosis and recurrence accepted second quantitative DSC-PWI. Final diagnosis was based on the histological results or follow-up results. Receiver operating curve analysis was used to explore the performance of qCBV.

Results

Twenty-nine patients (mean age: 61.3 ± 9.4 years old; male/female: 13/16) were assigned to the group of hypoperfusion group, and 26 patients (mean age: 58 ± 10.4 years old; male/female: 14/12) to hyperperfusion group. The mean qCBV values between hypoperfusion and hyperperfusion groups when recurred were not significantly different (3.17 ± 0.53 ml/100 g vs. 3.27 ± 0.47 ml/100 g, p = 0.63). qCBV was feasible to separate radionecrosis and recurrence in both groups (AUC=0.94 and AUC=0.93, separately).

Conclusion

Both premilitary hyperperfusion and hypoperfusion BMs would transform to a high microvascular density when recurs. qCBV is feasible to distinguish radionecrosis and recurrence among both kinds of BMs after GKRS.

Central Nervous System Metastases

The proportion of patients developing central nervous system (CNS) metastasis is increasing. Most are identified once symptomatic. Surgical resection is indicated for solitary or symptomatic brain metastases, separation surgery for compressive radioresistant spinal metastases, and instrumentation for unstable spinal lesions. Surgical biopsies are performed when histological diagnoses are required. Stereotactic radiosurgery is an option for limited small brain metastases and radioresistant spinal metastases. Whole-brain radiotherapy is reserved for extensive brain metastases and leptomeningeal disease with approaches to reduce cognitive side effects. Radiosensitive and inoperable spinal metastases typically receive external beam radiotherapy. Systemic therapy is increasingly being utilized for CNS metastases.

Deep learning-based detection and segmentation-assisted management of brain metastases

BACKGROUND

Three-dimensional T1 magnetization prepared rapid acquisition gradient echo (3D-T1-MPRAGE) is preferred in detecting brain metastases (BM) among MRI. We developed an automatic deep learning-based detection and segmentation method for BM (named BMDS net) on 3D-T1-MPRAGE images and evaluated its performance.

METHODS

The BMDS net is a cascaded 3D fully convolution network (FCN) to automatically detect and segment BM. In total, 1652 patients with 3D-T1-MPRAGE images from 3 hospitals (n = 1201, 231, and 220, respectively) were retrospectively included. Manual segmentations were obtained by a neuroradiologist and a radiation oncologist in a consensus reading in 3D-T1-MPRAGE images. Sensitivity, specificity, and dice ratio of the segmentation were evaluated. Specificity and sensitivity measure the fractions of relevant segmented voxels. Dice ratio was used to quantitatively measure the overlap between automatic and manual segmentation results. Paired samples t-tests and analysis of variance were employed for statistical analysis.

RESULTS

The BMDS net can detect all BM, providing a detection result with an accuracy of 100%. Automatic segmentations correlated strongly with manual segmentations through 4-fold cross-validation of the dataset with 1201 patients: the sensitivity was 0.96 ± 0.03 (range, 0.84-0.99), the specificity was 0.99 ± 0.0002 (range, 0.99-1.00), and the dice ratio was 0.85 ± 0.08 (range, 0.62-0.95) for total tumor volume. Similar performances on the other 2 datasets also demonstrate the robustness of BMDS net in correctly detecting and segmenting BM in various settings.

CONCLUSIONS

The BMDS net yields accurate detection and segmentation of BM automatically and could assist stereotactic radiotherapy management for diagnosis, therapy planning, and follow-up.

Radiomics Method for the Differential Diagnosis of Radionecrosis Versus Progression after Fractionated Stereotactic Body Radiotherapy for Brain Oligometastasis

Stereotactic radiotherapy (SRT) is recommended for treatment of brain oligometastasis (BoM) in patients with controlled primary disease. Where contrast enhancement enlargement occurs during follow-up, distinguishing between radionecrosis and progression presents a critical challenge. Without pathological confirmation, decision-making may be inappropriate and delayed. Quantitative imaging features extracted from routinely performed examinations are of interest in potentially addressing this problem. We explored the added value of the radiomics method for the differential diagnosis of these two entities. Twenty patients who received SRT for BoM, from any primary location, were included (8 radionecrosis, 12 progressions, pathologically confirmed). We assessed the clinical relevance of 1,766 radiomics features, extracted using IBEX software, from the first T1-weighted postcontrast magnetic resonance imaging (MRI) after SRT showing a lesion modification. We evaluated seven feature-selection methods and 12 classification methods in terms of respective predictive performance. The classification accuracy was measured using Cohen's kappa after leave-one-out cross-validation. In this work, the best predictive power reached was a Cohen's kappa of 0.68 (overall accuracy of 85%), expressing a strong agreement between the algorithm prediction and the histological gold standard. Prediction accuracy was 75% for radionecrosis, and 91% for progression. The area under a curve reached 0.83 using a bagging algorithm trained with the chi-square score features set. These findings indicated that the radiomics method is able to discriminate radionecrosis from progression in an accurate, early and noninvasive way. This promising study is a proof of concept, preceding a larger prospective study for defining a robust model to support decision-making in BoM. In summary, distinguishing between radionecrosis and progression is challenging without pathology. We built a classification model based on imaging data and machine learning. Using this model, we were able predict progression and radionecrosis in, respectively, 91% and 75% of cases.

Absolute CBV for the differentiation of recurrence and radionecrosis of brain metastases after gamma knife radiotherapy: a comparison with relative CBV

AIM

To investigate the efficiency of absolute cerebral blood volume (CBV) in the differentiation of tumour recurrence (TR) and radionecrosis (RN) in brain metastases (BM) and to evaluate the performance of absolute CBV compared to relative CBV (rCBV).

MATERIALS AND METHODS

Between March 2015 and June 2017, 46 patients with BM underwent quantitative dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) because new enhancement had been demonstrated in irradiated lesions after gamma knife radiotherapy. The patients were assigned to either the TR group or RN group on the basis of MR perfusion follow-up or histopathological outcome. Absolute CBV of lesions (CBVlesion) and contralateral normal appearing white matter (CBVNAWM) in both groups were obtained. Mean rCBV were calculated as CBVlesion/CBVNAWM, which was equal to rCBV using traditional DSC-PWI.

RESULTS

CBVlesion of TR alone was significantly higher than the other parameters in both groups (p<0.001, separately). CBVlesion had smaller interobserver difference than CBVNAWM and rCBV (p<0.001, separately). Although CBVlesion significantly correlated with rCBV (r=0.914, p<0.001) and both had a similar specificity (96%) in differential diagnosis, CBVlesion had a higher sensitivity (96.9% versus 90.9%) to predict the treatment outcome. The best cut-off value of CBVlesion was 21.8 ml/100 g.

CONCLUSION

Quantitative DSC-PWI is a powerful method for the assessment of radiosurgically treated brain metastases. Absolute CBV has higher diagnostic efficiency than rCBV, which enables an absolute quantification of the regional CBV and prediction of tumour response. These advantages promote the intra- and inter-patient quantitative image comparison across different institutions.

Postcontrast T1 Mapping for Differential Diagnosis of Recurrence and Radionecrosis after Gamma Knife Radiosurgery for Brain Metastasis

BACKGROUND AND PURPOSE

The differential diagnosis of radionecrosis and tumor recurrence in brain metastases is challenging. We investigated the diagnostic efficiency of postcontrast T1 mapping in solving this problem.

MATERIALS AND METHODS

Between March 2016 and June 2017, fifty-six patients with brain metastases who underwent contrast-enhanced cerebral T1 mapping were recruited for this prospective study. The findings revealed new enhancement after gamma knife radiosurgery. The subjects were assigned to radionecrosis and recurrence groups based on follow-up (median, 11.5 months) and histopathologic results. T1 values of lesions 5 (T1_5min) and 60 (T1_60min) minutes after administration of contrast agent and their difference (T1_differ) were compared between the 2 groups with the 2-tailed Mann-Whitney U test. Receiver operating characteristic curves were used to determine the optimum cutoff values for differential diagnosis.

RESULTS

There were significant differences between the 2 groups in T1_5min, T1_60min, and T1_differ values (P = .012, P = .004, and P < .001, respectively). Relative to T1_5min and T1_60min, T1_differ exhibited greater sensitivity and specificity (P < .001, respectively) in identifying radionecrosis. The optimum T1_differ value for differential diagnosis was 71.1 ms (area under the curve = 0.97; 95% CI, 0.93-1.00), with sensitivity and specificity of 81.5% and 96.5%, respectively.

CONCLUSIONS

Postcontrast T1 mapping is optimal for the differential diagnosis of radionecrosis and tumor recurrence. Among T1 parameters, T1_differ is the most powerful parameter for differential diagnosis. Advantages in terms of quantitative analysis and high resolution portend the wide use of postcontrast T1 mapping in the future.

Overview of PET Tracers for Brain Tumor Imaging

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

Brain metastases in gastrointestinal cancers: is there a role for surgery?

About 10% of all cancer patients will develop brain metastases during advanced disease progression. Interestingly, the vast majority of brain metastases occur in only three types of cancer: Melanoma, lung and breast cancer. In this review, we focus on summarizing the prognosis and impact of surgical resection of brain metastases originating from gastrointestinal cancers such as esophageal, gastric, pancreatic and colorectal cancer. The incidence of brain metastases is <1% in pancreatic and gastric cancer and <4% in esophageal and colorectal cancer. Overall, prognosis of these patients is very poor with a median survival in the range of only months. Interestingly, a substantial number of patients who had received surgical resection of brain metastases showed prolonged survival. However, it should be taken into account that all these studies were not randomized and it is likely that patients selected for surgical treatment presented with other important prognostic factors such as solitary brain metastases and exclusion of extra-cranial disease. Nevertheless, other reports have demonstrated long-term survival of patients upon resection of brain metastases originating from gastrointestinal cancers. Thus, it appears to be justified to consider aggressive surgical approaches for these patients.

EMPACT syndrome: limited evidence despite a high-risk cohort

Serious dermatologic adverse events such as erythema multiforme (EM) and Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) have been reported in patients receiving antiepileptic drugs (AEDs) and cranial radiotherapy (RT). Given the frequency of AED-associated rashes and the infrequency of serious dermatologic adverse events after cranial RT, we sought to further assess the prevalence of cutaneous eruptions in patients receiving an AED before and after cranial RT. We reviewed medical records of patients taking AEDs while undergoing RT for a high-grade glioma and recorded demographic, disease, and treatment parameters, as well as the development of rashes. Rashes were found in 19 % of patients taking AEDs. Phenytoin was most commonly implicated (93 %) in rash formation compared with other AEDs (P < 0.0001), both before and during RT. Most rashes (76 %) occurred before starting RT (P < 0.0001). However, of those during RT, most were associated with phenytoin compared with other AEDs (P = 0.002). One case of SJS was noted in a patient receiving phenytoin prior to RT. While rashes were slightly less prevalent in patients receiving temozolomide compared with those not receiving temozolomide (3.4 vs 4.8 %), this difference was not statistically significant (P = 0.65). Rashes are relatively common in patients receiving AEDs, with the highest incidence associated with phenytoin. However, the risk of serious dermatologic events is low. There did not appear to be an association between the receipt of cranial radiotherapy and the development of AED-associated rash with phenytoin or other AEDs.

Preservation of neurocognitive function and local control of 1 to 3 brain metastases treated with surgery and carmustine wafers

Background

Neurosurgical resection and whole-brain radiation therapy (WBRT) are accepted treatments for single and oligometastatic cancer to the brain. To avoid the decline in neurocognitive function (NCF) linked to WBRT, the authors conducted a prospective, multicenter, phase 2 study to determine whether surgery and carmustine wafers (CW), while deferring WBRT, could preserve NCF and achieve local control (LC).

Methods

NCF and LC were measured in 59 patients who underwent resection and received CW for a single (83%) or dominant (oligometastatic, 2 to 3 lesions) metastasis and received stereotactic radiosurgery (SRS) for tiny nodules not treated with resection plus CW. Preservation of NCF was defined as an improvement or a decline ≤1 standard deviation from baseline in 3 domains: memory, executive function, and fine motor skills, evaluated at 2-month intervals.

Results

Significant improvements in executive function and memory occurred throughout the 1-year follow-up. Preservation or improvement of NCF occurred in all 3 domains for the majority of patients at each of the 2-month intervals. NCF declined in only 1 patient. The chemowafers were well tolerated, and serious adverse events were reversible. There was local recurrence in 28% of the patients at 1-year follow-up.

Conclusions

Patients with brain metastases had improvements in their cognitive trajectory, especially memory and executive function, after treatment with resection plus CW. The rate of LC (78%) was comparable to historic rates of surgery with WBRT and superior to reports of WBRT alone. For patients who undergo resection for symptomatic or large-volume metastasis or for tissue diagnosis, the addition of CW can be considered as an option.

Bevacizumab as a treatment for radiation necrosis of brain metastases post stereotactic radiosurgery

BACKGROUND

Cerebral radiation necrosis (RN) is a difficult to treat complication of stereotactic radiosurgery (SRS) that can result in progressive neurologic decline. Currently, steroids are the standard of care treatment for brain RN despite their adverse effect profile and limited efficacy. The purpose of this study was to evaluate the treatment efficacy of cerebral RN to bevacizumab in patients with brain metastases previously treated with SRS.

METHODS

We retrospectively reviewed 14 lesions in 11 patients treated with bevacizumab for brain RN secondary to SRS for their brain metastases. Steroid dosing, RN-associated symptoms, and magnetic resonance imaging (MRI) scans were examined before, during, and after bevacizumab administration.

RESULTS

Of the 11 patients included, 6 had metastatic non-small cell lung cancer, and 5 had metastatic breast cancer. The mean percentage decrease in RN volume seen on T1 post-Gadolinium and fluid-attenuated inversion recovery (FLAIR) MRI at first follow-up, at a mean of 26 days (range, 15-43 days), was 64.4% and 64.3%, respectively. MRI changes were sustained on follow-up MRI scans, obtained at a mean of 33 days (range, 7-58 days) after bevacizumab discontinuation. After bevacizumab treatment, all patients initially receiving steroids had a reduction in steroid requirement, and all but one had an improvement in or stability of RN-associated symptoms. No patients experienced intratumoral bleeds or other adverse effects related to their bevacizumab treatment.

CONCLUSIONS

Bevacizumab is effective and safe for the treatment of RN after SRS for brain metastasis. In this context, bevacizumab offers symptomatic relief, a reduction in steroid requirement, and a dramatic radiographic response.

Surgery for brain metastases

The use of surgery in the treatment of brain metastases is controversial. Patients who present certain clinical characteristics may experience prolonged survival with resection compared with radiation therapy. Thus, for patients with a single metastatic lesion in the setting of well-controlled systemic cancer, surgery is highly indicated. Stereotactic radiosurgery (SRS) alone can provide a similar survival advantage, but when used as postoperative adjuvant therapy, patients experience extended survival times. Furthermore, surgery remains the only treatment option for patients with life-threatening neurological symptoms, who require immediate tumor debulking. Treatment of brain metastases requires a careful clinical assessment of individual patients, as different prognostic factors may indicate various modes or combinations of therapy. Since surgery is an effective method for achieving tumor management in particular cases, it remains an important consideration in the treatment algorithm for brain metastases.