Selective excision of metastatic brain tumors originating in the motor cortex with preservation of function

Linac-based stereotactic radiosurgery and fractionated stereotactic radiotherapy with a micro-multileaf collimator for brain metastasis in the primary motor cortex

This study aimed to assess the clinical outcomes of linear accelerators (linac)-based, stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (fSRT) with a micro-multileaf collimator for brain metastasis in the primary motor cortex (BMPMC). Thirty-five consecutive patients with BMPMC who were treated by linac-based SRS or fSRT between January 2012 and March 2020 were analyzed. BMPMC was defined as a tumor located in the precentral gyrus on gadolinium-enhanced magnetic resonance imaging (MRI) and T2-weghted imaging (T2WI). In total, 35 patients with 37 metastases were analyzed. The median follow-up time was 13 (range: 1-97) months. The tumor volume was 0.05-26.5 (median: 0.62) cm3. All patients were treated with SRS or fSRT using 35 Gy with 7 Gy per fraction daily. The median survival time (MST) was 16.9 months. The pretreatment KPS and RPA class significantly differed in terms of MST on the log-rank tests. Seven symptomatic patients had hemiparesis before SRS or fSRT. All symptomatic patients, except one with facial paresis and one who died within 3 months, experienced improvement at a 3 month follow-up. None of the patients presented with persistent radiation injury at the final follow-up. Two patients presented with grade 3 radiation-related central nervous system necrosis, which was assessed using the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. In BMPMC, SRS and fSRT had good tumor control and did not cause serious complications. Therefore, they are suitable treatment options with an acceptable safety profile.

Surgical Management of Brain Metastases in the Perirolandic Region

Brain metastases (BM) are the most frequent intracranial tumors, which may result in significant morbidity and mortality when the lesions involve the perirolandic region. Surgical intervention for BM in the perirolandic region is still under discussion even though prompt relief of mass effect and avoidance of necrosis together with brain edema may not be achieved by radiotherapy. More recently, several researchers attempt to evaluate the benefit of surgery for BM within this pivotal sensorimotor area. Nevertheless, data are sparse and optimal treatment paradigm is not yet widely described. Since the advance in intraoperative neuroimaging and neurophysiology, resection of BM in the perirolandic region has been proven to be safe and efficacious, sparing this eloquent area while retaining reasonably low morbidity rates. Although management of BM becomes much more tailored and multimodal, surgery remains the cornerstone and principles of resection as well as indications for surgery should be well defined. This is the first review concerning the characteristics of BM involving the perirolandic region and the current impact of surgical therapy for the lesions. Future perspectives of advanced neurosurgical techniques are also presented.

Early motor function after local treatment of brain metastases in the motor cortex region with stereotactic radiotherapy/radiosurgery or microsurgical resection: a retrospective study of two consecutive cohorts

Background

We compared the functional outcome and influential factors of two standard treatment modalities for central cerebral metastases: electrophysiological-controlled microsurgical resection (MSR) and stereotactic radiotherapy/stereotactic radiosurgery (SRT/SRS).

Methods

We performed a database search for central metastasis treatments during the period from January 2008 to September 2012 in two clinical registers: 1) register for intraoperative neuromonitoring (Department of Neurosurgery), and 2) prospective database for SRT/SRS (Department of Radiotherapy). Neurological status before and after treatment, Karnofsky performance index (KPI), histology, tumor localization and volume, and oncological status were standardized and pooled together for analysis. Muscle strength was graded on a scale of 0–5.

Results

We identified 27 MSR and 41 SRT/SRS cases from 68 treatments. The MSR-treated patients had significant less muscle strength in the upper and lower extremities before and after the treatment as compared to the patients receiving SRT/SRS. Muscle strength of the extremities did not change for patients receiving SRT/SRS, while MSR patients had significant improvement in lower extremity muscle strength (p = 0.05) and a non-significant improvement in the upper extremities. MSR showed significant improvement in hemiparesis as compared to radiotherapy, but this was accompanied with a significant deterioration of extremity muscle strength after surgery, as compared to SRT/SRS (improvement p = 0.04, deterioration p = 0.10).

Conclusion

Electrophysiologically guided microsurgery of central metastases had a significantly better functional outcome regarding hemiparesis. However, there was also a trend for less secondary neurological deterioration after SRT/SRS.

Trial registration

ISRCTN81776764. Retrospectively Registered 27 July 2017.

Surgical Resection of Non-Glial Tumors in the Motor Cortex

Background

Direct surgery to resect tumors in the motor cortex could improve neurological symptoms or cause novel motor weakness. The present study describes the neurological outcomes of patients after the surgical resection of non-glial tumors in the primary motor cortex.

Methods

The present study included 25 patients who had pathologically confirmed non-glial tumors in the motor cortex for which they underwent surgery. Tumor location was verified using anatomical landmarks on preoperative magnetic resonance imaging scans. All surgeries involved a craniotomy and tumor resection, especially use of the sulcal dissecting approach for intra-axial tumors.

Results

Of the 25 patients, 10 exhibited metastasis, 13 had a meningioma, and 2 had a cavernous malformation. Motor weakness and seizures were the most common symptoms, while 3 patients experienced only a headache. The tumor size was less than 20 mm in 4 patients, 20–40 mm in 14, and greater than 40 mm in seven. Of the 25 patients, 13 exhibited motor weakness prior to the operation, but most of these symptoms (76.9%) improved following surgery. On the other hand, eight patients experienced seizures prior to the surgery, and in three of these patients (37.5%), the seizures were not controlled after the surgery. In terms of surgical complications, a postoperative hematoma developed in one of the meningioma patients, and the patient's hemiparesis was aggravated.

Conclusion

The present findings show that careful and meticulous resection of non-glial tumors in the motor cortex can improve preoperative neurological signs, but it cannot completely control seizure activity.

The evolving clinical management of cerebral metastases

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

Lung Cancer Brain Metastases

Brain metastases are common among patients with lung cancer and have been associated with significant morbidity and limited survival. However, the treatment of brain metastases has evolved as the field has advanced in terms of central nervous system imaging, surgical technique, and radiotherapy technology. This has allowed patients to receive improved treatment with less toxicity and more durable benefit. In addition, there have been significant advances in systemic therapy for lung cancer in recent years, and several treatments including chemotherapy, targeted therapy, and immunotherapy exhibit activity in the central nervous system. Utilizing systemic therapy for treating brain metastases can avoid or delay local therapy and often allows patients to receive effective treatment for both intracranial and extracranial disease. Determining the appropriate treatment for patients with lung cancer brain metastases therefore requires a clear understanding of intracranial disease burden, tumor histology, molecular characteristics, and overall cancer prognosis. This review provides updates on the current state of surgery and radiotherapy for the treatment of brain metastases, as well as an overview of systemic therapy options that may be effective in select patients with intracranial metastases from lung cancer.

Functional approach using intraoperative brain mapping and neurophysiological monitoring for the surgical treatment of brain metastases in the central region

OBJECTIVE Brain metastases are the most frequent intracranial malignant tumor in adults. Surgical intervention for metastases in eloquent areas remains controversial and challenging. Even when metastases are not infiltrating intra-parenchymal tumors, eloquent areas can be affected. Therefore, this study aimed to describe the role of a functional guided approach for the resection of brain metastases in the central region. METHODS Thirty-three patients (19 men and 14 women) with perirolandic metastases who were treated at the authors' institution were reviewed. All participants underwent resection using a functional guided approach, which consisted of using intraoperative brain mapping and/or neurophysiological monitoring to aid in the resection, depending on the functionality of the brain parenchyma surrounding each metastasis. Motor and sensory functions were monitored in all patients, and supplementary motor and language area functions were assessed in 5 and 4 patients, respectively. Clinical data were analyzed at presentation, discharge, and the 6-month follow-up. RESULTS The most frequent presenting symptom was seizure, followed by paresis. Gross-total removal of the metastasis was achieved in 31 patients (93.9%). There were 6 deaths during the follow-up period. After the removal of the metastasis, 6 patients (18.2%) presented with transient neurological worsening, of whom 4 had worsening of motor function impairment and 2 had acquired new sensory disturbances. Total recovery was achieved before the 3rd month of follow-up in all cases. Excluding those patients who died due to the progression of systemic illness, 88.9% of patients had a Karnofsky Performance Scale score greater than 80% at the 6-month follow-up. The mean survival time was 24.4 months after surgery. CONCLUSIONS The implementation of intraoperative electrical brain stimulation techniques in the resection of central region metastases may improve surgical planning and resection and may spare eloquent areas. This approach also facilitates maximal resection in these and other critical functional areas, thereby helping to avoid new postoperative neurological deficits. Avoiding permanent neurological deficits is critical for a good quality of life, especially in patients with a life expectancy of over a year.

Surgery on motor area metastasis

The role of surgery on central area metastasis remains unclear, and outcome data are still controversial. The aim of our study is to analyze the predictive value of clinical and surgical data on motor and functional outcome of patients, taking into account new emerging data on boundary irregularity of brain metastasis. We retrospectively analyzed 47 consecutive patients who underwent surgery assisted by neurophysiologic monitoring for a solitary metastasis in central area between 2010 and 2013. Inclusion criteria were as follows: good functional status (Karnofsky Performance Status (KPS) ≥70), controlled systemic disease, and absence of extra-cranial dissemination. At 1-month follow up, motor and functional outcomes were compared with preoperative clinical status, response to corticosteroids, extent of tumor resection, boundary irregularity, and size of tumor. Gross total resection was achieved in 93.6% of cases. In preoperative symptomatic patients, motor outcome (according to Medical Research Council grading scale) improved in 55.5% and worsened in 16.7%, while functional outcome (according to KPS score) improved in 50% and worsened in 14.2% of cases. No worsening occurred in preoperative asymptomatic patients. Motor outcome resulted to be not correlated with preoperative deficits, tumor volume, or preoperative response to corticosteroid treatment. Remarkably, motor outcome and extent of surgical resection appeared strongly correlated with tumor boundary irregularity (p < 0.05). Surgery with neurophysiologic monitoring on motor area metastasis can improve functional and motor condition in selected patients. Tumor volume does not represent a limit in surgery. The high correlation between clinical outcome, resection rate, and tumor boundary irregularity strengthens a new belief on the infiltrative growing pattern of brain metastasis. Motor function was evaluated according to Medical Research Council grading scale (Ott et al. 2014) while functional status was assessed according to KPS score.

Experiences in surgery of primary malignant brain tumours in the primary sensori-motor cortex practical recommendations and results of a single institution

OBJECTIVE

Tumour resection in the Rolandic region is a challenge. Aim of this study is to review a series of patients malignant glioma surgery in the Rolandic region which was performed by combinations of neuronavigation, sonography, 5-aminolevulinic acid fluorescence guided (5-ALA) surgery and intraoperative electrophysiological monitoring (IOM).

METHODS

29 patients suffering malignant gliomas in the motor cortex (17) and sensory cortex (12) were analyzed with respect to functional outcome and grade of resections.

RESULTS

Improvement of motor function was seen in 41.5% one week after surgery, 41.5% were stable, only 17% deteriorated. After three months patients had an improvement of motor function in 56%, of Karnofsky Score (KPS) 27% and sensory function was improved in 8%. Deterioration of motor function was seen in 16%, in sensory function 4% and in KPS 28% after three months. 25% showed no residual tumour in early post surgical contrast enhanced MRI. 10% had less than 2% residual tumour and 15% had 2-5% residual tumour.

CONCLUSIONS

Preoperative functional neuroimaging, neuronavigation for planning the surgical approach and resection margins, intraoperative sonography and 5-ALA guided surgery in combination with the application of IOM shows that functional outcome and total to subtotal resection of malignant glioma in the Rolandic region is feasible.

Current approaches to the treatment of metastatic brain tumours

Metastatic tumours involving the brain overshadow primary brain neoplasms in frequency and are an important complication in the overall management of many cancers. Importantly, advances are being made in understanding the molecular biology underlying the initial development and eventual proliferation of brain metastases. Surgery and radiation remain the cornerstones of the therapy for symptomatic lesions; however, image-based guidance is improving surgical technique to maximize the preservation of normal tissue, while more sophisticated approaches to radiation therapy are being used to minimize the long-standing concerns over the toxicity of whole-brain radiation protocols used in the past. Furthermore, the burgeoning knowledge of tumour biology has facilitated the entry of systemically administered therapies into the clinic. Responses to these targeted interventions have ranged from substantial toxicity with no control of disease to periods of useful tumour control with no decrement in performance status of the treated individual. This experience enables recognition of the limits of targeted therapy, but has also informed methods to optimize this approach. This Review focuses on the clinically relevant molecular biology of brain metastases, and summarizes the current applications of these data to imaging, surgery, radiation therapy, cytotoxic chemotherapy and targeted therapy.

Selective excision of cerebral metastases from the precentral gyrus

BACKGROUND

The surgical management of cerebral metastases to the eloquent cortex is a controversial topic. Precentral gyrus lesions are often treated with whole brain radiation therapy (WBRT) or stereotactic radiosurgery (SRS) because of the concern for causing new or worsened postoperative neurological deficits. However, there is evidence in the literature that radiation therapy carries significant risk of complication. We present a series of patients who were symptomatic from a precentral gyrus metastasis and underwent surgical excision.

METHODS

During a 2-year period from 2010 to 2012, 17 consecutive patients harboring a cerebral metastasis within the precentral gyrus underwent microsurgical resection. All patients were discussed at a multi-disciplinary tumor board. The prerequisite for neurosurgical treatment was stable systemic disease and life expectancy greater than 6 months as determined by the patient's oncologist. Patients also were required to harbor a symptomatic lesion within the motor cortex, defined as the precentral gyrus.

RESULTS

We present the 3-month neurological outcome for this group of patients. Surgery was uneventful and without any severe perioperative complications in all 17 patients. At 3 month follow up, symptoms had improved or been stabilized in 94.1% of patients and were worsened in 5.9%.

CONCLUSION

Our results have shown that surgery for cerebral metastases in the precentral gyrus can be done safely and improve or stabilize the neurological function of most patients. Microsurgical resection of precentral gyrus metastases should be a treatment option for patients with single or multiple lesions who present a focal neurologic deficit. This can be performed safely and without intraoperative cortical mapping.

Radiosurgery for large brain metastases

PURPOSE

To determine the efficacy and safety of radiosurgery in patients with large brain metastases treated with radiosurgery.

PATIENTS AND METHODS

Eighty patients with large brain metastases (>14 cm(3)) were treated with radiosurgery between 1998 and 2009. The mean age was 59 ± 11 years, and 49 (61.3%) were men. Neurologic symptoms were identified in 77 patients (96.3%), and 30 (37.5%) exhibited a dependent functional status. The primary disease was under control in 36 patients (45.0%), and 44 (55.0%) had a single lesion. The mean tumor volume was 22.4 ± 8.8 cm(3), and the mean marginal dose prescribed was 13.8 ± 2.2 Gy.

RESULTS

The median survival time from radiosurgery was 7.9 months (95% confidence interval [CI], 5.343-10.46), and the 1-year survival rate was 39.2%. Functional improvement within 1-4 months or the maintenance of the initial independent status was observed in 48 (60.0%) and 20 (25.0%) patients after radiosurgery, respectively. Control of the primary disease, a marginal dose of ≥11 Gy, and a tumor volume ≥26 cm(3) were significantly associated with overall survival (hazard ratio, 0.479; p = .018; 95% CI, 0.261-0.880; hazard ratio, 0.350; p = .004; 95% CI, 0.171-0.718; hazard ratio, 2.307; p = .006; 95% CI, 1.274-4.180, respectively). Unacceptable radiation-related toxicities (Radiation Toxicity Oncology Group central nervous system toxicity Grade 3, 4, and 5 in 7, 6, and 2 patients, respectively) developed in 15 patients (18.8%).

CONCLUSION

Radiosurgery seems to have a comparable efficacy with surgery for large brain metastases. However, the rate of radiation-related toxicities after radiosurgery should be considered when deciding on a treatment modality.

Operative treatment of subcortical metastatic tumours in the central region

The operative treatment of subcortical metastatic tumours within the paracentral area is still under discussion. Against the background of possible new postoperative neurological deficits and of evolving new radio oncological techniques, the indication for surgery is limited only to a subgroup of patients. In this retrospective study we present the clinical results after operative treatment of metastases within the central and paracentral brain region, with an emphasis on the short-term and mid-term functional outcome. We report on 20 patients suffering from subcortical brain metastases within the primary sensorimotor area, with a median volume on MRI-scans of 8.18 cm³. Patients were admitted to our department with a progressive hemiparesis (n = 11), focal seizures (n = 6) or other unspecific symptoms (n = 3) like headache, nausea, and neuropsychological disturbances, respectively. After updated MRI- and fMRI-scanning, intensive electrophysiological testing including MEP-brain mapping and interdisciplinary tumour-board discussion of each case, those patients were evaluated for surgery. Early postoperative control was done by MRI within the first 48 h. Follow-up took place in our outpatient department, assessing clinical criteria two and 6 weeks postoperatively, followed by clinical control and MRI-scans every 3 months. In all patients, surgery was performed under general anaesthesia, cranial neuro navigation and intraoperative motor cortex stimulation. Surgery and the early postoperative course were uneventful in all cases. After a 6 months follow-up, two patients had died. The motor deficits improved in seven patients and remained unchanged in four cases. One patient suffered from a new persistent hemiparesis. A temporary paresis occurred in two cases. In five patients there was no motor deficit pre- and postoperatively. The Karnofsky Performance Status improved in ten patients 6 months after surgery. Quality of Life, measured by the FACT-Br score, improved in 12 patients and remained unchanged in one patient. With modern techniques like fMRI-guided cranial neuronavigation and intraoperative neuromonitoring including direct stimulation of the motor cortex, microsurgical resection of subcortical paracentral metastases is feasible with an acceptable risk of neurological deterioration. Even preexistent deficits can improve with positive influence on the quality of life for oncological patients, being disabled by the symptoms caused by the cerebral lesion.

Advantages and disadvantages of awake surgery for brain tumours in the primary motor cortex: institutional experience and review of literature

Patients undergoing awake surgery for resection of brain tumours in the primary motor cortex (M1) are at high risk of developing new motor deficits. Thus, use of this procedure requires consideration of several important points, including the optimal modality to localise M1 on the affected side and the overall advantages and disadvantages of the procedure. In our experience with awake surgery for 21 brain tumours located in the M1 from January 2004 through October 2008, we found that functional magnetic resonance imaging was the most reliable modality in terms of localising the M1 and that the anatomic relationship between motor tracts and brain tumours is a critical determinant of postoperative motor function. Other considerations, including potential complications of this procedure and relative efficacy and safety versus surgery under general anaesthesia for patients with brain tumours in the M1, are discussed.

Current therapeutic approaches in patients with brain metastases

The development of brain metastases is often viewed as the end stage of a disease course and engenders skepticism about the efficacy of treatment. Aggressive management of brain metastases is effective in both symptom palliation and the prolongation of life. The majority of patients with controlled intracranial metastases will expire from systemic disease rather than from recurrence of these metastases. Single brain metastases should be treated with surgical resection or stereotactic radiosurgery, though it is unclear at this time if one modality is more effective than the other. Surgical resection is preferred when a pathologic diagnosis is needed, for tumors larger than 3.5 cm, or when immediate tumor mass decompression is required. Stereotactic radiosurgery (SRS) should be applied for single tumors less than 3.5 cm in surgically inaccessible areas and for patients who are not surgical candidates. Small tumors (ie, < 3.5 cm) that cause minimal edema and are surgically accessible may be treated with either surgery or SRS. There is controversy over whether whole brain radiation therapy (WBRT) can be omitted following surgical resection or SRS. Omission of WBRT increases intracranial tumor recurrence; however, this has not been correlated with decreased survival. Clinicians who choose to omit upfront WBRT are obligated to monitor the patient closely for intracranial recurrence, at which time further salvage therapy in the form of surgery, SRS, or WBRT may be considered. Histology is of particular importance when considering WBRT for patients with radioresistant tumors such as melanoma, renal cell carcinoma, or sarcoma. WBRT may be of less clinical benefit in this setting. Chemotherapy has been demonstrated to improve response rates when used as an adjunct to radiation therapy. These improvements in response rates have not been correlated with an improvement in median survival. Noncytotoxic radiosensitizing agents such as motexafin and efaproxiral show promise. Phase III trials to assess the benefit of motexafin in patients with metastatic lung cancer and efaproxiral in patients with metastatic breast cancer are ongoing. Targeted therapies offer promise in achieving therapeutic efficacy while minimizing side effects. Surgical adjuncts such as BCNU (carmustine) wafers and the GliaSite Radiation System (Cytyc Corporation, Marlborough, MA) may be useful in the future in achieving optimal local tumor control.

Indications for resection and radiosurgery for brain metastases

PURPOSE OF REVIEW

This review is focused on indications for resection, stereotactic radiosurgery, and fractionated radiotherapy for patients with single or multiple brain metastases. Our purpose is to summarize the indications and effect of these management approaches.

RECENT FINDINGS

Brain metastases are a frequent challenge in patients with extracranial solid cancers. More than 40% of patients with cancer will develop metastases to the brain. While some patients present with large lesions and symptoms related to mass effect, many are diagnosed when asymptomatic tumors are found on screening studies. The main options for patients with brain metastases are whole brain radiation therapy, surgical resection, and stereotactic radiosurgery. Much information regarding outcomes, survival, management morbidity, and quality of life is available. Randomized, class III clinical trials demonstrate that multimodal therapy is important for both life quality and extended survival. A better understanding of the current therapeutic options should result in improvements in patient care.

SUMMARY

This is a review of the literature from May 2004 to June 2005 with special attention on publications related to effect on quality of life with different procedures and therapies.