The efficacy and limitations of stereotactic radiosurgery as a salvage treatment after failed whole brain radiotherapy for brain metastases

Factors associated with the local control of brain metastases: a systematic search and machine learning application

BACKGROUND

Enhancing Local Control (LC) of brain metastases is pivotal for improving overall survival, which makes the prediction of local treatment failure a crucial aspect of treatment planning. Understanding the factors that influence LC of brain metastases is imperative for optimizing treatment strategies and subsequently extending overall survival. Machine learning algorithms may help to identify factors that predict outcomes.

METHODS

This paper systematically reviews these factors associated with LC to select candidate predictor features for a practical application of predictive modeling. A systematic literature search was conducted to identify studies in which the LC of brain metastases is assessed for adult patients. EMBASE, PubMed, Web-of-Science, and the Cochrane Database were searched up to December 24, 2020. All studies investigating the LC of brain metastases as one of the endpoints were included, regardless of primary tumor type or treatment type. We first grouped studies based on primary tumor types resulting in lung, breast, and melanoma groups. Studies that did not focus on a specific primary cancer type were grouped based on treatment types resulting in surgery, SRT, and whole-brain radiotherapy groups. For each group, significant factors associated with LC were identified and discussed. As a second project, we assessed the practical importance of selected features in predicting LC after Stereotactic Radiotherapy (SRT) with a Random Forest machine learning model. Accuracy and Area Under the Curve (AUC) of the Random Forest model, trained with the list of factors that were found to be associated with LC for the SRT treatment group, were reported.

RESULTS

The systematic literature search identified 6270 unique records. After screening titles and abstracts, 410 full texts were considered, and ultimately 159 studies were included for review. Most of the studies focused on the LC of the brain metastases for a specific primary tumor type or after a specific treatment type. Higher SRT radiation dose was found to be associated with better LC in lung cancer, breast cancer, and melanoma groups. Also, a higher dose was associated with better LC in the SRT group, while higher tumor volume was associated with worse LC in this group. The Random Forest model predicted the LC of brain metastases with an accuracy of 80% and an AUC of 0.84.

CONCLUSION

This paper thoroughly examines factors associated with LC in brain metastases and highlights the translational value of our findings for selecting variables to predict LC in a sample of patients who underwent SRT. The prediction model holds great promise for clinicians, offering a valuable tool to predict personalized treatment outcomes and foresee the impact of changes in treatment characteristics such as radiation dose.

Opportunities and Alternatives of Modern Radiation Oncology and Surgery for the Management of Resectable Brain Metastases

Postsurgical radiotherapy (RT) has been early proven to prevent local tumor recurrence, initially performed with whole brain RT (WBRT). Subsequent to disadvantageous cognitive sequalae for the patient and the broad distribution of modern linear accelerators, focal irradiation of the tumor has omitted WBRT in most cases. In many studies, the effectiveness of local RT of the resection cavity, either as single-fraction stereotactic radiosurgery (SRS) or hypo-fractionated stereotactic RT (hFSRT), has been demonstrated to be effective and safe. However, whereas prospective high-level incidence is still lacking on which dose and fractionation scheme is the best choice for the patient, further ablative techniques have come into play. Neoadjuvant SRS (N-SRS) prior to resection combines straightforward target delineation with an accelerated post-surgical phase, allowing an earlier start of systemic treatment or rehabilitation as indicated. In addition, low-energy intraoperative RT (IORT) on the surgical bed has been introduced as another alternative to external beam RT, offering sterilization of the cavity surface with steep dose gradients towards the healthy brain. This consensus paper summarizes current local treatment strategies for resectable brain metastases regarding available data and patient-centered decision-making.

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.

Novel prognostic classification predicts overall survival of patients receiving salvage whole-brain radiotherapy for recurrent brain metastasis from breast cancer: A recursive partitioning analysis (KROG 16-12)

Background

To investigate outcomes of salvage whole-brain radiotherapy (WBRT) for recurrent brain metastases (BM) from breast cancer (BC), to identify prognostic factors of overall survival (OS), and to propose a novel prognostic classification for OS in these patients.

Materials and methods

We identified 54 patients who had received salvage WBRT as the second brain-focused treatment for recurrent BM from BC (2000–2014). The median follow-up duration was 4.9 months. A recursive partitioning analysis (RPA) was conducted to develop a model to predict OS at the time of salvage WBRT.

Results

The median OS was 6.8 months. OS according to BC-specific graded prognostic assessment (breast-GPA), modified breast-GPA, and updated breast-GPA did not represent our cohort. In the multivariate analysis, a long time before salvage WBRT (≥16 months), control of primary BC or extracranial metastases, systemic treatment after salvage WBRT, and administration of a biologically effective dose for an α/β of 10 Gy (BED10) of salvage WBRT >37.5 Gy showed superior OS. We proposed three RPA classes based on the control of both primary BC and extracranial metastasis and BED10 of salvage WBRT: class I, class II, and class III. In this model, patients with class I experienced the best OS (34.6 months; class II, 5.0 months; class III, 2.4 months; P < 0.001).

Conclusions

In our RPA classification according to the control of both primary BC and extracranial metastasis and the dose of salvage WBRT, significant differences in OS were observed. The subsequent use of a systemic treatment showed better OS.

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Multicenter retrospective study of salvage WBRT for recurrent brain metastasis.

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Subsequent use of systemic treatment after salvage WBRT showing better OS.

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Limitations of previous graded prognostic assessments for recurrent brain metastasis.

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Novel RPA classification consisting of four simple clinical factors predicts OS.

Validation and comparison of Breast Graded Prognostic Assessment scores in patients with breast cancer and brain metastases

PURPOSE

Brain metastases (BM) occur in 15-35% of patients with metastatic breast cancer, conferring poor prognosis and impairing quality of life. Clinical scores have been developed to classify patients according to their prognosis. We aimed to check the utility of the Breast Graded Prognostic Assessment (B-GPA) and its modified version (mB-GPA) and compare them in routine clinical practice.

METHODS

This is an ambispective study including all patients with breast cancer BM treated in a single cancer comprehensive center. We analyzed the overall survival (OS) from BM diagnosis until death. The Kaplan-Meier method and Cox proportional hazard regression model were used in the analyses. ROC curves were performed to compare both scores.

RESULTS

We included 169 patients; median age was 50 years. HER2-positive and triple negative patients were 33.7% and 20.7%, respectively. At the last follow-up, 90% of the patients had died. Median OS was 12 months (95% confidence interval 8.0-16.0 months). OS was worse in patients with > 3 BM and in patients with triple negative subtype.

CONCLUSIONS

In our series, we confirm that B-GPA and mB-GPA scores correlated with prognosis. ROC curves showed that B-GPA and mB-GPA have similar prognostic capabilities, slightly in favor of mB-GPA.

Laser interstitial thermal therapy as an adjunct therapy in brain tumors: A meta-analysis and comparison with stereotactic radiotherapy

BACKGROUND

Minimally invasive procedures are gaining widespread acceptance in difficult-to-access brain tumor treatment. Stereotactic radiosurgery (SRS) is the preferred choice, however, laser interstitial thermal therapy (LITT) has emerged as a tumor cytoreduction technique. The present meta-analysis compared current SRS therapy with LITT in brain tumors.

METHODS

A search was performed in Lilacs, PubMed, and Cochrane database. Patient's demographics, tumor location, therapy used, Karnofsky performance status score before treatment, and patient's outcome (median overall survival, progression-free survival, and adverse events) data were extracted from studies. The risk of bias was assessed by Cochrane collaboration tool.

RESULTS

Twenty-five studies were included in this meta-analysis. LITT and SRS MOS in brain metastasis patients were 12.8 months' versus 9.8 months (ranges 9.3-16.3 and 8.3-9.8; P = 0.02), respectively. In a combined comparison of adverse effects among LITT versus SRS in brain metastasis, we found 15% reduction in absolute risk difference (-0.16; 95% confidence interval P < 0.0001).

CONCLUSION

We could not state that LITT treatment is an optimal alternative therapy for difficult-to-access brain tumors due to the lack of systematic data that were reported in our pooled studies. However, our results identified a positive effect in lowering the absolute risk of adverse events compared with SRS therapy. Therefore, randomized trials are encouraged to ascertain LITT role, as upfront or postoperative/post-SRS therapy for brain tumor treatment.

Repeated stereotactic radiosurgery for recurrent brain metastases: An effective strategy to control intracranial oligometastatic disease

Due to improvements in systemic therapies and longer survivals, cancer patients frequently present with recurrent brain metastases (BM). The optimal therapeutic strategies for limited brain relapse remain undefined. We analyzed tumor control and survival in patients treated with salvage focal radiotherapy in our center. Thirty-three patients with 112 BM received salvage stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT) for local or regional recurrences. Local progression was observed in 11 BM (9.8 %). After 1 year, 72 % of patients were free of distant brain failure, and the 2-year overall survival (OS) was 37.7 %. No increase in toxicity or neurologically related deaths were observed. The 2- and 3-year whole brain radiation therapy free survival (WFS) rates were 92.9 % and 77.4 %, respectively. Hence, focal radiotherapy is a feasible salvage of recurrent BM in selected group of patients with limited brain disease, achieving a maintained intracranial control and less neurological toxicity.

Linac-Based Radiosurgery for Patients With Brain Oligometastases From a Breast Primary, in the Trastuzumab Era-Impact of Tumor Phenotype and Prescribed SRS Dose

Background: The role of stereotactic radiosurgery (SRS) in the treatment of limited numbers of brain metastases in selected breast cancer patients is well-established. Aims: To analyse outcome from a single institutional experience with SRS, to identify any significant prognostic factors and to assess the influence of Her-2, estrogen receptor status, and prescribed dose on outcome. Methods: The medical records of 56 patients treated at in a single institution between 2009 and 2014 were reviewed. Demographic, treatment related and outcome data were analyzed to identify prognostic factors in this patient population. The primary endpoints were overall survival and local control. Secondary endpoint was distant intra-cranial progression-free survival. Results: The median follow- up time for the entire cohort was 10.33 months (1.25-97.28). The overall median survival was 12.5months (95%CI = 5.8-19.2), with 53.3%, and 35.8% surviving at 1- and 2- years post-SRS. After adjustment for the effect of Her 2 status, uncontrolled extra-cranial disease at the time of SRS predicted for shorter survival (HR for death = 3.1, 95% CI = 1.4-6.9, p = 0.006). At the time of death, 75% of the patients had active, uncontrolled intra-cranial disease, with 56% these patients presenting intra-cranial disease only. Sustained local control was observed in 56 (59.6%) of 94 treated metastases. In univariate analysis, Her2 status, ERHer2 group status?, and prescribed SRS dose were highly significant for local progression free-survival (LPFS). After adjustment for the effect of Her 2 status, patients receiving 12-16 Gy can expect shorter LPFS than those receiving 18-20 Gy (HR = 1.7, 95% CI = 1.0-2.8, p = 0.043). After adjustment for the effect of dose group, patients with Her 2 negative cancer can expect shorter LPFS than those with Her 2 positive cancer (HR = 2.6, 95% CI = 1.5-4.4, p < 0.0005). Use of prior WBRT did not impact survival, local or distant intra-cranial progression-free survival. Conclusions: Survival outcome is similar to the published literature. Improved outcomes are observed in patients with Her 2-positive, controlled extracranial disease at the time of SRS and higher SRS dose delivered. Achieving intra-cranial control appears to be an important factor for the survival of the breast cancer patients in the era of targeted therapies.

Reirradiation of Recurrent Brain Metastases: Where Do We Stand?

Brain metastases occur in a large portion of patients with cancer. Although advances in radiotherapy have helped to improve survival, they have also raised questions regarding the best modality for retreatment in the context of recurrent disease. The spectrum of treatment options for recurrent intracranial metastatic disease after previous radiotherapy includes salvage stereotactic radiosurgery, whole brain radiotherapy, and brachytherapy. We have comprehensively reviewed the existing data on the efficacy and toxicity of the various reirradiation treatment modalities. We examined the key clinical considerations that guide patient selection, such as dose, tumor size, interval to retreatment, and local control and survival rates.

Adaptive hypofractionated gamma knife radiosurgery in the acute management of brainstem metastases

Background:

Intrinsic brainstem metastases are life-threatening neoplasms requiring rapid, effective intervention. Microsurgery is considered not feasible in most cases and systemic treatment seldom provides a successful outcome. In this context, radiation therapy remains the best option but adverse radiation effects (ARE) remain a major concern. A dose-adaptive gamma knife procedure coined as Rapid Rescue Radiosurgery (3R) offers the possibility to treat these lesions whilst reducing the risk of ARE evolvement. We report the results of 3R applied to a group of patients with brainstem metastases.

Methods:

Eight patients with nine brainstem metastases, having undergone three separate, dose-adapted gamma knife radiosurgery (GKRS) procedures over 7 days, were retrospectively analyzed in terms of tumor volume reduction, local control rates, and ARE-development under the period of treatment and at least 6 months after treatment completion.

Results:

Mean peripheral doses at GKRS 1, GKRS 2, and GKRS 3 were 7.4, 7.7, and 8.2 Gy (range 6–9 Gy) set at the 35–50% isodose lines. Mean tumor volume reduction between GKRS 1 and GKRS 3 was −15% and −56% at first follow-up. Four patients developed radiologic signs of ARE but remained clinically asymptomatic. One patient developed a local recurrence at 34 months. Mean survival from GKRS 1 was 13 months. Two patients were still alive at the time of paper submission (10 and 23 months from GKRS 1).

Conclusions:

In this study, 3R proved effective in terms of tumor volume reduction, rescue/preservation of neurological function, and limited ARE evolvement.

Local control and overall survival after frameless radiosurgery: A single center experience

Introduction

Stereotactic radiosurgery (SRS) has been increasingly advocated for 1-3 small brain metastases. The goal of this study was to evaluate the clinical results in patients with brain metastases treated with LINAC-based SRS using a thermoplastic mask (non-invasive fixation system) and Image-Guided Radiotherapy (IGRT).

Material and Methods

In this single-institution study 48 patients with 77 brain metastases were treated between February 2012 and January 2014. The prescribed dose was 20 Gy or 18 Gy as a single fraction. SRS was performed with a True Beam STX Novalis Radiosurgery LINAC (Varian Medical Systems). The verification of positioning was done using the BrainLAB ExacTrac ® X-ray 6D system and cone-beam CT.

Results

In 69 of 77 treated brain metastases (90%) the follow-up was documented on MR imaging performed every 3 months. Mean follow-up time was 10.86 months. Estimated 1-year local control was 83%, using the Kaplan-Meier method. In 7/69 brain metastases (10%) local failure (LF) was diagnosed. Median progression free survival (PFS) was 3.73 months, largely due to distant brain relapse. A GTV of ≤2.0 cm³ was significantly associated with a better PFS than a GTV >2.0 cm³. Extracranial stable disease and GTV ≤2.5 cm³ were significant predictors of OS.We observed 2 cases of radiation necrosis diagnosed by histology after surgical resection. No other cases of severe side effects (CTACE ≥ 3) were observed.

Conclusion

LINAC-based frameless SRS with the BrainLAB Mask using the BrainLAB ExacTrac ® X-ray 6D system for patient positioning is well tolerated, safe and leads to favorable crude local control of 90%. In our experience, local control after frameless (ringless) SRS is as good as ring-based SRS reported in literature. Without invasive head fixation, radiotherapy is more comfortable for patients.

[Hypofractionated stereotactic radiotherapy for brain metastasis: Benefit of additional whole brain radiotherapy?]

PURPOSE

To study overall survival, risk of neurological death, local recurrence and development of new brain metastasis in patients treated for brain oligometastases with hypofractionated stereotactic radiotherapy with CyberKnife^®, according to the association or not with an additional whole brain irradiation.

PATIENTS AND METHODS

Institutional retrospective study of 102 patients treated for one to three brain metastasis: 76 with exclusive hypofractionated stereotactic radiotherapy and 26 with hypofractionated stereotactic radiotherapy and whole brain irradiation. Objectives were assessed and compared between these two groups according to the Kaplan-Meier method and Cox model.

RESULTS

Median follow-up was 18.8 months. There were no difference between exclusive hypofractionated stereotactic radiotherapy and hypofractionated stereotactic radiotherapy with whole brain irradiation for overall survival (respective median 21.5 and 20.1 months), risk of neurological death (respectively 9.2% and 15.4% at one year). At one year: the risk of cerebral progressive disease was greater in the group receiving exclusive hypofractionated stereotactic radiotherapy (respectively 43.4% vs. 26.2%, P=0.043), the risk of local recurrence was 25% versus 17.6% (P=0.28) and the development of new brain metastasis was 23.7% versus 11.5% (P=0.27). After salvage treatments, crude local control was similar in the two groups, respectively 78.6% and 73.5%. Whole brain irradiation has been avoided for 72.4% of patients in the group receving exclusive hypofractionated stereotactic radiotherapy.

CONCLUSION

Whole brain irradiation improves local control of brain metastatic disease in addition to hypofractionated stereotactic radiotherapy. Sparing whole brain irradiation for salvage treatments only does not affect overall survival or risk of neurological death in selected patients with favourable prognosis.

Brain metastasis reirradiation in patients with advanced breast cancer

The outcome of recurrent brain metastasis is dismal. This study aims to assess the clinical outcomes and toxicity of reirradiation as a salvage treatment for progressive brain metastasis in patients with advanced breast cancer. Between July 2005 and September 2014, the medical records of 56 patients with brain metastasis from breast cancer were retrospectively reviewed. Of these patients, 39 received whole-brain radiotherapy (WBRT) followed by stereotactic radiosurgery (SRS) reirradiation (Group 1), and 17 received SRS followed by WBRT reirradiation (Group 2). Overall survival (OS) and brain progression-free survival rates/times were calculated using the Kaplan-Meier method. Prognostic factors were evaluated using the Cox proportional hazards model. Change in neurologic function was also assessed. The median OS was 10.8 months (range, 1.3-56.8 months). In Group 1, the median PFS time (PFS-1) was 6.5 months and the OS time was 11.4 months. Multivariate analysis revealed that longer OS was significantly associated with a high Karnofsky performance score (KPS) (P = 0.004), controlled extracranial metastasis (P = 0.001) and a good response to reirradiation (P = 0.034). In Group 2, the median PFS time (PFS-2) after reirradiation was 8.5 months and the OS time was 10.8 months. Multivariate analysis revealed that longer OS was significantly associated with a high KPS (P = 0.018). The majority of the patients had improved or stable neurological function. Reirradiation is an effective and a safe treatment for patients with brain metastases from breast cancer. It might delay the progression of intracranial disease and improve neurological function. A suitable patient selection for reirradiation was suggested.

Is upfront stereotactic radiosurgery a rational treatment option for very elderly patients with brain metastases? A retrospective analysis of 106 consecutive patients age 80 years and older

Background

Advanced age has been shown to be a factor predicting poor survival in patients with brain metastases (BM). There have been only a few studies focusing on stereotactic radiosurgery (SRS) for elderly BM patients. The present study aimed to investigate the efficacy and limitations of SRS for very elderly BM patients.

Methods

This was a retrospective observational study analyzing 106 consecutive patients (69 males/37 females) age 80 years and older who received upfront Gamma Knife SRS for BM between January 2009 and October 2015. The median age was 84 years, and the median Karnofsky performance status (KPS) was 70. Fifty-two patients had a solitary BM, and others multiple BM. The median cumulative tumor volume was 3.9 mL and the median dose prescribed was 20 Gy. Overall survival (OS), neurological death rates and distant and local intracranial tumor control rates were analyzed.

Results

No patients were lost to follow-up. Six-month and 12-month OS rates were 54% and 32%, respectively. The median OS time was 7.1 months. Competing risks analysis showed that 6-month and 12-month neurological death rates were 8% and 11%, respectively. In total, 245 / 311 tumors (79%) in 82 patients (77%) with sufficient radiological follow-up data were evaluated. Six-month and 12-month distant BM recurrence rates (per patient) after SRS were 17% and 25%, respectively. Six-month and 12-month rates of local tumor control (per lesion) were 94% and 89%, respectively. Repeat SRS, salvage WBRT and surgical resection were subsequently required in 25, 4 and 1 patient, respectively. Proportional hazard regression analysis showed that KPS ≥ 70 (HR: 0.444, P < .001), controlled primary disease/no extracranial metastases (HR: 0.361, P < .001) and female sex (HR: 0.569, P = 0.028) were independent factors predicting better OS. Similarly, tumor volume (>2 mL) was the only factor predicting a higher rate of local control failure (HR: 12.8, P = 0.003).

Conclusions

The present study suggested an upfront SRS strategy to offer a feasible and effective treatment option for very elderly patients with limited BM. In the majority of patients, neurological death could be delayed or even prevented.

Cesium-131 brachytherapy for recurrent brain metastases: durable salvage treatment for previously irradiated metastatic disease

OBJECTIVE Managing patients whose intraparenchymal brain metastases recur after radiotherapy remains a challenge. Intraoperative cesium-131 (Cs-131) brachytherapy performed at the time of neurosurgical resection may represent an excellent salvage treatment option. The authors evaluated the outcomes of this novel treatment with permanent intraoperative Cs-131 brachytherapy. METHODS Thirteen patients with 15 metastases to the brain that recurred after stereotactic radiosurgery and/or whole brain radiotherapy were treated between 2010 and 2015. Stranded Cs-131 seeds were placed as a permanent volume implant. Prescription dose was 80 Gy at 5-mm depth from the resection cavity surface. The primary end point was resection cavity freedom from progression (FFP). Resection cavity freedom from progression (FFP), regional FFP, distant FFP, median survival, overall survival (OS), and toxicity were assessed. RESULTS The median duration of follow-up after salvage treatment was 5 months (range 0.5-18 months). The patients' median age was 64 years (range 51-74 years). The median resected tumor diameter was 2.9 cm (range 1.0-5.6 cm). The median number of seeds implanted was 19 (range 10-40), with a median activity per seed of 2.25 U (range 1.98-3.01 U) and median total activity of 39.6 U (range 20.0-95.2 U). The 1-year actuarial local FFP was 83.3%. The median OS was 7 months, and 1-year OS was 24.7%. Complications included infection (3), pseudomeningocele (1), seizure (1), and asymptomatic radionecrosis (RN) (1). CONCLUSIONS After failure of prior irradiation of brain metastases, re-irradiation with intraoperative Cs-131 brachytherapy implants provides durable local control and limits the risk of RN. The authors' initial experience demonstrates that this treatment approach is well tolerated and safe for patients with previously irradiated tumors after failure of more than 1 radiotherapy regimen and that it results in excellent response rates and minimal toxicity.

[Surgery for metastases, anatomical and ethical limits. Special aspect: oligometastases]

The surgical resection of metastases is nowadays feasible in selected patients with multifocal metastatic disease due to the implementation of interdisciplinary multimodal therapeutic options. Anatomical limitations do not seem to represent obstacles which cannot be overcome because of the development of new surgical techniques. The cornerstone of the selection of patients is the correct staging diagnosis achieved through modern diagnostic tools; however, surgery alone does not always offer acceptable survival and recurrence-free rates. Furthermore, in every complex surgical procedure there is the risk of morbidity and mortality; therefore, parameters such as alternative therapeutic modalities, the individual situation of the patient and tumor biology have to be considered in order to make the correct selection of patients. This is one of the major future challenges and should never be driven by unfounded hopes and expectations of the patients. The same principle also applies for brain metastases, which represent the most common brain tumors. Approximately 70 % of patients with brain metastases have 1-3 lesions (oligometastases). Treatment is now individualized and the goal of therapy has shifted towards long-term survival (≥ 24 months) and improved quality of life. Under this aspect surgery is one of the important treatment options, particularly in patients with a single metastasis or oligometastases. Furthermore, approximately 20 % of patients who have recurrent brain metastases, successfully undergo a complete resection of tumors and with a Karnofsky performance status (KPS) score > 70 show a long-term survival of ≥ 24 months.

Adaptive hypofractionated gamma knife radiosurgery for a large brainstem metastasis

Background:

To demonstrate how adaptive hypofractionated radiosurgery by gamma knife (GK) can be successfully utilized to treat a large brainstem metastasis - a novel approach to a challenging clinical situation.

Case Description:

A 42-year-old woman, diagnosed with metastatic nonsmall cell lung cancer in July 2011, initially treated with chemotherapy and tyrosine kinase inhibitors, developed multiple brain metastases March 2013, with subsequent whole brain radiotherapy, after which a magnetic resonance imaging (MRI) showed a significant volume regression of all brain metastases. A follow-up MRI in October 2013 revealed a growing brainstem lesion of 26 mm. Linear accelerator-based radiotherapy and microsurgery were judged contraindicated, why the decision was made to treat the patient with three separate radiosurgical sessions during the course of 1 week, with an 18% tumor volume reduction demonstrated after the last treatment. Follow-up MRI 2.5 months after her radiosurgical treatment showed a tumor volume reduction of 67% compared to the 1^st day of treatment. Later on, the patient developed a radiation-induced perilesional edema although without major clinical implications. An MRI at 12 months and 18-fluoro-deoxyglucose positron emission tomography of the brain at 13 months showed decreased edema with no signs of tumor recurrence. Despite disease progression during the last months of her life, the patient's condition remained overall acceptable.

Conclusion:

GK-based stereotactic adaptive hypofractionation proved to be effective to achieve tumor control while limiting local adverse reactions. This surgical modality should be considered when managing larger brain lesions in critical areas.

Stereotactic radiosurgery for brain metastasis in non-small cell lung cancer

Purpose

Stereotactic radiosurgery (SRS) has been introduced for small-sized single and oligo-metastases in the brain. The aim of this study is to assess treatment outcome, efficacy, and prognostic variables associated with survival and intracranial recurrence.

Materials and Methods

This study retrospectively reviewed 123 targets in 64 patients with non-small cell lung cancer (NSCLC) treated with SRS between January 2006 and December 2012. Treatment responses were evaluated using magnetic resonance imaging. Overall survival (OS) and intracranial progression-free survival (IPFS) were determined.

Results

The median follow-up was 13.9 months. The median OS and IPFS were 14.1 and 8.9 months, respectively. Fifty-seven patients died during the follow-up period. The 5-year local control rate was achieved in 85% of 108 evaluated targets. The 1- and 2-year OS rates were 55% and 28%, respectively. On univariate analysis, primary disease control (p < 0.001), the Eastern Cooperative Oncology Group (ECOG) performance status (0-1 vs. 2; p = 0.002), recursive partitioning analysis class (1 vs. 2; p = 0.001), and age (<65 vs. ≥65 years; p = 0.036) were significant predictive factors for OS. Primary disease control (p = 0.041) and ECOG status (p = 0.017) were the significant prognostic factors for IPFS. Four patients experienced radiation necrosis.

Conclusion

SRS is a safe and effective local treatment for brain metastases in patients with NSCLC. Uncontrolled primary lung disease and ECOG status were significant predictors of OS and intracranial failure. SRS might be a tailored treatment option along with careful follow-up of the intracranial and primary lung disease status.

Treatment of Brain Metastases

Brain metastases (BMs) occur in 10% to 20% of adult patients with cancer, and with increased surveillance and improved systemic control, the incidence is likely to grow. Despite multimodal treatment, prognosis remains poor. Current evidence supports use of whole-brain radiation therapy when patients present with multiple BMs. However, its associated cognitive impairment is a major deterrent in patients likely to live longer than 6 months. In patients with oligometastases (one to three metastases) and even some with multiple lesions less than 3 to 4 cm, especially if the primary tumor is considered radiotherapy resistant, stereotactic radiosurgery is recommended; if the BMs are greater than 4 cm, surgical resection with or without postoperative whole-brain radiation therapy should be considered. There is increasing evidence that systemic therapy, including targeted therapy and immunotherapy, is effective against BM and may be an early choice, especially in patients with sensitive primary tumors. In patients with progressive systemic disease, limited treatment options, and poor performance status, best supportive care may be appropriate. Regardless of treatment goals, use of corticosteroids or antiepileptic medications is helpful in symptomatic patients. In this review, we provide a summary of current therapy, as well as developments in the treatment of BM from solid tumors.

Comparative Effectiveness Analysis of Treatment Options for Single Brain Metastasis

BACKGROUND

Brain metastases (BMs) occur in up to 30% of patients with cancer. Treatments include surgery, whole-brain radiotherapy (WBRT), and stereotactic radiosurgery (SRS), alone or in combination. Although guidelines exist, data to inform individualized approaches to therapy remain sparse. We sought to compare semiquantitatively the effectiveness of various modalities in the treatment of single brain metastasis.

METHODS

We performed a comparative effectiveness analysis (CEA) that integrated efficacy, cost, and quality of life (QoL) data for alternate BM treatments. Efficacy data were obtained from a comprehensive review of current literature. Cost estimates were based on publicly available data. QoL data included the Karnofsky Performance Status (KPS) and other questionnaires. Six treatment strategies using combinations of surgery, WBRT, and SRS were compared with decision tree software.

RESULTS

The clinical efficacy, cost, and QoL effects of each strategy were scored semiquantitatively. We constructed a model to integrate individual preferences regarding the relative importance of efficacy, QoL, and cost to provide personalized rankings of the effectiveness of each strategy.

CONCLUSION

The choice of strategy must be individualized for patients with a single BM. Our CEA and decision model combines empirical data with patient priorities to produce a ranking of alternate management strategies.

Stereotactic radiosurgery for multiple brain metastases

Stereotactic radiosurgery (SRS) alone has become one of the treatment options for patients with 1-4 metastases as the detrimental effects of whole brain radiation therapy on neurocognition and quality of life are becoming well known. Multiple randomized control trials also failed to show overall survival benefit of adding whole brain radiation therapy to SRS. However, the role of SRS in multiple brain metastases, especially those with ≥ 4 tumors, remains controversial. The literature is emerging, and the limited evidence suggests that the local control benefit is independent of the number of metastases, and that patients with more than four brain metastases have similar overall survival compared to those with 2-4 tumors. This review aims at summarizing the current evidence of SRS for multiple brain metastases, divided into limited (2-3) and multiple (≥ 4) lesions. It also reviews the technical aspects and cost-effectiveness of SRS.

Stereotactic radiosurgery for treatment of brain metastases. A report of the DEGRO Working Group on Stereotactic Radiotherapy

BACKGROUND

This report from the Working Group on Stereotaktische Radiotherapie of the German Society of Radiation Oncology (Deutsche Gesellschaft für Radioonkologie, DEGRO) provides recommendations for the use of stereotactic radiosurgery (SRS) on patients with brain metastases. It considers existing international guidelines and details them where appropriate.

RESULTS AND DISCUSSION

The main recommendations are: Patients with solid tumors except germ cell tumors and small-cell lung cancer with a life expectancy of more than 3 months suffering from a single brain metastasis of less than 3 cm in diameter should be considered for SRS. Especially when metastases are not amenable to surgery, are located in the brain stem, and have no mass effect, SRS should be offered to the patient. For multiple (two to four) metastases--all less than 2.5 cm in diameter--in patients with a life expectancy of more than 3 months, SRS should be used rather than whole-brain radiotherapy (WBRT). Adjuvant WBRT after SRS for both single and multiple (two to four) metastases increases local control and reduces the frequency of distant brain metastases, but does not prolong survival when compared with SRS and salvage treatment. As WBRT carries the risk of inducing neurocognitive damage, it seems reasonable to withhold WBRT for as long as possible.

CONCLUSION

A single (marginal) dose of 20 Gy is a reasonable choice that balances the effect on the treated lesion (local control, partial remission) against the risk of late side effects (radionecrosis). Higher doses (22-25 Gy) may be used for smaller (< 1 cm) lesions, while a dose reduction to 18 Gy may be necessary for lesions greater than 2.5-3 cm. As the infiltration zone of the brain metastases is usually small, the GTV-CTV (gross tumor volume-clinical target volume) margin should be in the range of 0-1 mm. The CTV-PTV (planning target volume) margin depends on the treatment technique and should lie in the range of 0-2 mm. Distant brain recurrences fulfilling the aforementioned criteria can be treated with SRS irrespective of previous WBRT.

Stereotactic radiosurgery boost to the resection cavity for cerebral metastases: Report of overall survival, complications, and corticosteroid protocol

Background:

This report focuses on the overall survival and complications associated with treatment of cerebral metastases with surgical resection followed by stereotactic radiosurgery (SRS). Management and complications of corticosteroid therapy are underreported in the literature but represent an important source of morbidity for patients.

Methods:

Fifty-nine consecutive patients underwent surgical resection of a cerebral metastasis followed by SRS to the cavity. Patient charts were reviewed retrospectively to ascertain overall survival, local control, surgical complications, SRS complications, and corticosteroid complications.

Results:

Our mean follow-up was 14.4 months (median 12.0 months, range 0.9-62.9 months). Median overall survival in this series was 15.25 months and local control was 98.3%. There was a statistically significant survival benefit conferred by Radiation Therapy Oncology Group recursive partitioning analysis Classes 1 and 2. The surgical complication rate was 6.8% while the SRS complication rate was 2.4%. Corticosteroid complications are reported and dependence at 1 month was 20.3%, at 3 months 6.8%, at 6 months 1.7%, and at 12 months no patients remained on corticosteroid therapy.

Conclusions:

Overall survival and local control with this treatment paradigm compare well to the other published literature. Complications associated with this patient population are low. A corticosteroid tapering protocol is proposed and demonstrated lower rates of steroid-related complications and dependence than previously reported.