Safety of multiple stereotactic radiosurgery treatments for multiple brain lesions

Molecular Biology of Brain Metastases

Brain metastases (BMs) often occur in patients with lung cancer, breast cancer, and melanoma and are the leading cause of morbidity and mortality. The incidence of BM has increased with advanced neuroimaging and prolonged overall survival of cancer patients. With the advancement of local treatment modalities, including stereotactic radiosurgery and navigation-guided microsurgery, BM can be controlled long-term, even in cases with multiple lesions. However, radiation/chemotherapeutic agents are also toxic to the brain, usually irreversibly and cumulatively, and it remains difficult to completely cure BM. Thus, we must understand the molecular events that begin and sustain BM to develop effective targeted therapies and tools to prevent local and distant treatment failure. BM most often spreads hematogenously, and the blood-brain barrier (BBB) presents the first hurdle for disseminated tumor cells (DTCs) entering the brain parenchyma. Nevertheless, how the DTCs cross the BBB and settle on relatively infertile central nervous system tissue remains unknown. Even after successfully taking up residence in the brain, the unique tumor microenvironment is marked by restricted aerobic glycolysis metabolism and limited lymphocyte infiltration. Brain organotropism, certain phenotype of primary cancers that favors brain metastasis, may result from somatic mutation or epigenetic modulation. Recent studies revealed that exosome secretion from primary cancer or over-expression of proteolytic enzymes can "pre-condition" brain vasculoendothelial cells. The concept of the "metastatic niche," where resident DTCs remain dormant and protected from systemic chemotherapy and antigen exposure before proliferation, is supported by clinical observation of BM in patients clearing systemic cancer and experimental evidence of the interaction between cancer cells and tumor-infiltrating lymphocytes. This review examines extant research on the metastatic cascade of BM through the molecular events that create and sustain BM to reveal clues that can assist the development of effective targeted therapies that treat established BMs and prevent BM recurrence.

Efficacy and Safety of a Second Course of Stereotactic Radiation Therapy for Locally Recurrent Brain Metastases: A Systematic Review

Simple Summary

Approximately 30% of patients diagnosed with cancer will ultimately develop brain metastases. Many improvements have been made in systemic and local cancer treatments, which have increased overall survival but also, as a consequence, the number of patients who present with local recurrence following intracranial stereotactic radiotherapy. The management of these recurrences remains controversial. The aim of our review is to evaluate the efficacy and tolerance of a second course of stereotactic radiotherapy.

Abstract

Recent advances in cancer treatments have increased overall survival and consequently, local failures (LFs) after stereotactic radiotherapy/radiosurgery (SRS/SRT) have become more frequent. LF following SRS or SRT may be treated with a second course of SRS (SRS2) or SRT (SRT2). However, there is no consensus on whenever to consider reirradiation. A literature search was conducted according to PRISMA guidelines. Analysis included 13 studies: 329 patients (388 metastases) with a SRS2 and 135 patients (161 metastases) with a SRT2. The 1-year local control rate ranged from 46.5% to 88.3%. Factors leading to poorer LC were histology (melanoma) and lack of prior whole-brain radiation therapy, large tumor size and lower dose at SRS2/SRT2, poorer response at first SRS/SRT, poorer performance status, and no controlled extracranial disease. The rate of radionecrosis (RN) ranged from 2% to 36%. Patients who had a large tumor volume, higher dose and higher value of prescription isodose line at SRS2/SRT2, and large overlap between brain volume irradiated at SRS1/SRT1 and SRS2/SRT2 at doses of 18 and 12 Gy had a higher risk of developing RN. Prospective studies involving a larger number of patients are still needed to determine the best management of patients with local recurrence of brain metastases

Patient perspectives on frame versus mask immobilization for gamma knife stereotactic radiosurgery

PURPOSE

To assess patient experiences and perspectives following Gamma Knife (GK) stereotactic radiosurgery (SRS) using frame versus mask immobilization.

METHODS

Patients who received GK-SRS using both frame and mask immobilization were included in this study. One-on-one semi-structured interviews, led by a third-party expert, were used to gain insight into the patient experience. To reduce memory bias of either immobilization device, patients underwent the interview at their follow-up appointment. Initial assessment of patient transcriptions was completed by one study staff; a second member reviewed transcripts for thematic saturation. All interviews were independently coded for themes to minimize interpretation bias.

RESULTS

Fifteen patients were consented; 12 were successfully interviewed (3 lost due to deteriorating health status). Interviews ranged from 30 to 60 min in duration. The most common patient concern regarding the frame was pain (9 patients), while the primary concerns with the mask system were the ability to remain still (6 patients) and claustrophobia (4 patients). Eleven patients chose the mask as their preferred choice in terms of their overall experience. Two themes emerged during the interviews that spoke to patient satisfaction with each process: unexpected pain with frame placement; and tightness experienced while wearing the mask during treatment.

CONCLUSIONS

From the patient perspective there was overwhelming agreement that the mask was the preferred choice for GK-SRS. The patient experience could be improved by enhanced education to better prepare patients on what to expect during the frame placement and mask treatment processes.

Clinical Experience of Bevacizumab for Radiation Necrosis in Patients with Brain Metastasis

Background

As the application of radiotherapy to brain metastasis (BM) increases, the incidence of radiation necrosis (RN) as a late toxicity of radiotherapy also increases. However, no specific treatment for RN is indicated except long-term steroids. Here, we summarize the clinical results of bevacizumab (BEV) for RN.

Methods

Ten patients with RN who were treated with BEV monotherapy (7 mg/kg) were retrospectively reviewed. RN diagnosis was made using MRI with or without perfusion MRI. Radiological response was based on Response Assessment in Neuro-Oncology criteria for BM. The initial response was observed after 2 cycles every 2 weeks, and maintenance observed after 3 cycles every 3–6 weeks of increasing length intervals.

Results

The initial response of gadolinium (Gd) enhancement diameter maintained stable disease (SD) in 9 patients, and 1 patient showed partial response (PR). The initial fluid-attenuated inversion recovery (FLAIR) response showed PR in 4 patients and SD in 6 patients. The best radiological response was observed in 9 patients. Gd enhancement response was 6 PR and 3 SD between 15–43 weeks. Reduction of FLAIR showed PR in 5 patients and SD in 4 patients. Clinical improvement was observed in all but 1 patient. Five patients were maintained on protocol with durable response up to 23 cycles. However, 2 patients stopped treatment due to primary cancer progression, 1 patient received surgical removal from tumor recurrence, and 1 patient changed to systemic chemotherapy for new BM. Grade 3 intractable hypertension occurred in 1 patient who had already received antihypertensive medication.

Conclusion

BEV treatment for RN from BM radiotherapy resulted in favorable radiological (60%) and clinical responses (90%). Side effects were expectable and controllable. We anticipate prospective clinical trials to verify the effect of BEV monotherapy for RN.

Stereotactic reirradiation for local failure of brain metastases following previous radiosurgery: Systematic review and meta-analysis

INTRODUCTION

Local failure (LF) following stereotactic radiosurgery (SRS) of brain metastases (BM) may be treated with a second course of SRS (SRS2), though this procedure may increase the risk of symptomatic radionecrosis (RN).

METHODS

A literature search was conducted according to PRISMA to identify studies reporting LF, overall survival (OS) and RN rates following SRS2. Meta-analysis was performed to identify predictors of RN.

RESULTS

Analysis included 11 studies (335 patients,389 metastases). Pooled 1-year LF was 24 %(CI95 % 19-30 %): heterogeneity was acceptable (I2 = 21.4 %). Median pooled OS was 14 months (Confidence Interval 95 %, CI95 % 8.8-22.0 months). Cumulative crude RN rate was 13 % (95 %CI 8 %-19 %), with acceptable heterogeneity (I2 = 40.3 %). Subgroup analysis showed higher RN incidence in studies with median patient age ≥59 years (13 % [95 %CI 8 %-19 %] vs 7 %[95 %CI 3 %-12 %], p = 0.004) and lower incidence following prior Whole Brain Radiotherapy (WBRT, 19 %[95 %CI 13 %-25 %] vs 7%[95 %CI 3 %-13 %], p = 0.004).

CONCLUSIONS

SRS2 is an effective strategy for in-site recurrence of BM previously treated with SRS.

Fractionated stereotactic radiosurgery for locally recurrent brain metastases after failed stereotactic radiosurgery

AIMS AND BACKGROUND

There is scant data on the utility of repeated radiosurgery for management of locally recurrent brain metastases after upfront stereotactic radiosurgery (SRS). Most studies have used single-fraction SRS for repeated radiosurgery, and the use of fractionated stereotactic radiosurgery (f-SRS) in this setting has been poorly addressed. In this study, we assessed the utility of f-SRS for the management of locally recurrent brain metastases after failed upfront single-fraction SRS and report our single-center experience.

METHODS AND STUDY DESIGN

A total of 30 patients receiving f-SRS for locally recurrent brain metastases after upfront single-fraction SRS at our department between September 2011 and September 2017 were retrospectively evaluated for local control (LC), toxicity, and overall survival outcomes.

RESULTS

Median age and Karnofsky performance status were 57 (range: 38-78 years) and 80 (range: 70-100) at repeated radiosurgery (SRS2). The median time interval between the two radiosurgery applications was 13.5 months (range: 3.7-49 months). LC after SRS2 was 83.3%. Radionecrosis developed in 4 of the 30 lesions after SRS2, and total rate of radionecrosis was 13.3%. Statistical analysis revealed that the volume of planning target volume (PTV) at SRS2 was significantly associated with radionecrosis (P = 0.014). The volume of PTV was >13 cm³ at SRS2 in all patients with radionecrosis.

CONCLUSION

A repeated course of radiosurgery in the form of f-SRS may be a viable therapeutic option for the management of locally recurrent brain metastases after failed upfront SRS with high LC rates and an acceptable toxicity profile despite the need for further supporting evidence.

Repeated Courses of Radiosurgery for New Brain Metastases to Defer Whole Brain Radiotherapy: Feasibility and Outcome With Validation of the New Prognostic Metric Brain Metastasis Velocity

Purpose: Stereotactic radiosurgery (SRS) is the preferred primary treatment option for patients with a limited number of asymptomatic brain metastases. In case of relapse after initial SRS the optimal salvage treatment is not well defined. Within this retrospective analysis, we investigated the feasibility of repeated courses of SRS to defer Whole-Brain Radiation Therapy (WBRT) and aimed to derive prognostic factors for patient selection. Materials and Methods: From 2014 until 2017, 42 patients with 197 brain metastases have been treated with multiple courses of SRS at our institution. Treatment was delivered as single fraction (18 or 20 Gy) or hypo-fractionated (6 fractions with 5 Gy) radiosurgery. Regular follow-up included clinical examination and contrast-enhanced cMRI at 3-4 months' intervals. Besides clinical and treatment related factors, brain metastasis velocity (BMV) as a newly described clinical prognostic metric was included and calculated between first and second treatment. Results: A median number of 1 lesion (range: 1-13) per course and a median of 2 courses (range: 2-6) per patient were administered resulting in a median of 4 (range: 2-14) metastases treated over time per patient. The median interval between SRS courses was 5.8 months (range: 0.9-35 months). With a median follow-up of 17.4 months (range: 4.6-45.5 months) after the first course of treatment, a local control rate of 84% was observed after 1 year and 67% after 2 years. Median time to out-of-field-brain-failure (OOFBF) was 7 months (95%CI 4-8 months). WBRT as a salvage treatment was eventually required in 7 patients (16.6%). Median overall survival (OS) has not been reached. Grouped by ds-GPA (≤ 2 vs. >2) the survival curves showed a significant split (p = 0.039). OS differed also significantly between BMV-risk groups when grouped into low vs. intermediate/high risk groups (p = 0.025). No grade 4 or 5 acute or late toxicity was observed. Conclusion: In selected patients with relapse after SRS for brain metastases, repeat courses of SRS were safe and minimized the need for rescue WBRT. The innovative, yet easy to calculate metric BMV may facilitate treatment decisions as a prognostic factor for OS.

Dosimetric and localization accuracy of Elekta high definition dynamic radiosurgery

BACKGROUND AND PURPOSE

With the increasingly prominent role of stereotactic radiosurgery in radiation therapy, there is a clinical need for robust, efficient, and accurate solutions for targeting multiple sites with one patient setup. The end-to-end accuracy of high definition dynamic radiosurgery with Elekta treatment planning and delivery systems was investigated in this study.

MATERIALS AND METHODS

A patient-derived CT scan was used to create a radiosurgery plan to seven targets in the brain. Monaco was used for treatment planning using 5 VMAT non-coplanar arcs. Prior to delivery, 3D-printed phantoms from RTsafe were ordered including a gel phantom for 3D dosimetry, phantom with 2D film insert, and an ion chamber phantom for point dose measurement. Delivery was performed using the Elekta VersaHD, XVI cone-beam CT, and HexaPOD six degree of freedom tabletop.

RESULTS

Absolute dose accuracy was verified within 2%. 3D global gamma analysis in the film measurement revealed 3%/2 mm passing rates >95%. Gel dosimetry 3D global gamma analysis (3%/2 mm) were above 90% for all targets with the exception of one. Results were indicative of typical end-to-end accuracies (<1 mm spatial uncertainty, 2% dose accuracy) within 4 cm of isocenter. Beyond 4 cm, 2 mm accuracy was found.

CONCLUSIONS

High definition dynamic radiosurgery expands clinically acceptable stereotactic accuracy to a sphere around isocenter allowing for radiosurgery of several targets with one setup with a high degree of dosimetric precision. Gel dosimetry proved to be an essential tool for the validation of the 3D dose distributions in this technique.

Cumulative Doses to Brain and Other Critical Structures After Multisession Gamma Knife Stereotactic Radiosurgery for Treatment of Multiple Metastatic Tumors

Purpose

Repeat stereotactic radiosurgery (SRS) is an attractive alternative to whole brain radiation therapy (WBRT) for treatment of recurrent brain metastases (BM). The purpose of this study is to determine the cumulative doses to the brain and critical normal structures in patients who underwent repeat courses of Gamma Knife (GK) SRS.

Materials and methods

We retrospectively identified ten patients who received at least three GK-SRS sessions for multiply recurrent BM at our institution from 2013 to 2016. We used Velocity™ 3.1.0 software to co-register the magnetic resonance imaging images and the dose data of all treatment sessions for each patient. The cumulative doses to brain, lenses, eyes, brainstem, optic nerves, chiasm, and hippocampi were calculated. Dose–volume histograms, as well as the mean, median and maximum doses of these structures, were analyzed.

Results

The median number of SRS was five sessions (range = 3–7 sessions) per patient over a median treatment span of 510 days (112–1,197 days), whereas the median number of metastatic tumors treated per patient was 25.0 (10–63). The median of the total tumor volume was 9.5 cc (2.3–75.9 cc). The median of the mean cumulative dose to the whole brain was 4.1 Gy (1.7–16.4 Gy). The medians of the maximum doses to the critical structures were as follows: brainstem, 6.1 Gy (2.2–28.9 Gy), chiasm, 3.9 Gy (1.8–10.8 Gy), right optic nerve, 2.9 Gy (1.2–9.0 Gy), and left optic nerve, 2.6 Gy (1.0–6.5 Gy). The medians of the mean and maximum cumulative doses to the hippocampi were 3.4 Gy (1.0–14.4 Gy) and 13.8 Gy (1.5–39.3 Gy), respectively. The median survival for the entire cohort was 26.7 months, and no patients developed radiation necrosis.

Conclusion

Our study demonstrated that multisession GKSRS could be delivered with low cumulative doses to critical normal structures. Further studies are required to fully establish its role as an alternative treatment strategy to WBRT for the treatment of multiply recurrent BM.

Three or More Courses of Stereotactic Radiosurgery for Patients with Multiply Recurrent Brain Metastases

BACKGROUND

Although patients with brain metastasis are treated with primary stereotactic radiosurgery (SRS), the use of salvage therapies and their consequence remains understudied.

OBJECTIVE

To study the intracranial recurrence patterns and salvage therapies for patients who underwent multiple SRS courses.

METHODS

A retrospective review was performed of 59 patients with brain metastases who underwent ≥3 SRS courses for new lesions. Cox regression analyzed factors predictive for overall survival.

RESULTS

The median age at diagnosis was 52 years. Over time, patients underwent a median of 3 courses of SRS (range: 3-8) to a total of 765 different brain metastases. The 6-month risk of distant intracranial recurrence after the first SRS treatment was 64% (95% confidence interval: 52%-77%). Overall survival was 40% (95% confidence interval: 28%-53%) at 24 months. Only 24 patients (41%) had a decline in their Karnofsky Performance Status ≤70 at last office visit. Quality of life was preserved among 77% of patients at 12 months, with 45% experiencing clinically significant improvement during clinical follow-up. Radiation necrosis developed in 10 patients (17%). On multivariate analysis, gender (males, Hazard Ratio [HR]: 2.0, P < .05), Karnofsky Performance Status ≤80 (HR 3.2, P < .001), extracranial metastases (HR: 3.6, P < .001), and a distant intracranial recurrence ≤3 months from initial to repeat SRS (HR: 3.8, P < .001) were associated with a poorer survival.

CONCLUSION

In selected patients, performing ≥3 SRS courses controls intracranial disease. Patients may need salvage SRS for distant intracranial relapse, but focal retreatments are associated with modest toxicity, do not appear to negatively affect a patient's performance status, and help preserve quality of life.

Treatment of high numbers of brain metastases with Gamma Knife radiosurgery: a review

Effectiveness of stereotactic radiosurgery (SRS) has been shown in patients with one to four brain metastases. Work has been done to evaluate the role of SRS alone treatment without whole-brain radiation therapy in patients with more than four metastases. A recent multiinstitutional JLGK 0901 prospective study revealed the class-2 evidence that SRS without whole-brain radiation therapy is an effective treatment for patients up to 10 metastatic lesions. Several retrospective studies exist to show the efficacy and safety of SRS for patients with even more than 10 lesions. However, patient selection is very critical for SRS alone treatment. The PubMed database was searched using combinations of search terms and synonyms for multiple brain metastases, Gamma Knife and SRS published between January 1, 2005 and January 1, 2015 in order to address the effectiveness of Gamma Knife for patients with multiple brain metastases. Good performance status, controlled primary disease, total treated tumor volume of 15 cm(3) or less have been found to be significant predictors for survival among patients with two or more brain lesions. The data suggest that SRS can be used and whole brain radiation therapy can be withheld in selected patients with multiple lesions to avoid acute or chronic adverse effects, especially neurocognitive decline, without causing survival disadvantage. In this review, we assessed the evidence for SRS treatment of patients with multiple brain metastases.

Gamma knife stereotactic radiosurgery for the management of incidentally-identified brain metastasis from non-small cell lung cancer

Initial staging workup of non-small cell lung cancer (NSCLC) patients has led to increased identification of incidental brain metastases in patients who otherwise have minimal or no neurologic symptoms. We present our experience treating these metastases with stereotactic radiosurgery (SRS) alone and compare outcomes to those of patients with brain metastases treated with other strategies. We queried our neuro-oncology and radiation oncology databases for patients with incidentally-identified NSCLC brain metastases treated with upfront SRS alone between 1997 and 2006. We performed a retrospective analysis to evaluate outcomes in these patients. We found 26 patients with incidentally-identified NSCLC brain metastases (KPS 90-100) treated with SRS alone within 60 days of diagnosis of the metastases. These patients underwent SRS at a median 15 days from diagnosis to an average of 1.6 lesions (range: 1-7), with a mean lesion volume of 1.86 cm(3). The median prescription was 24 Gy delivered to the median 53% isodose line. The median survival for these patients was 8.2 months (mean 12.3 months) from diagnosis of brain metastases. Local CNS progression occurred in 2 patients (7.7%, mean 229.7 days). Survival was not statistically different from similar patients treated with whole brain radiotherapy (WBRT) (P = 0.98), WBRT + Surgery (P = 0.07) or WBRT + SRS (P = 0.62). Patients with incidentally-identified NSCLC brain metastases treated with SRS alone may achieve a survival rate comparable to patients managed with other standard therapeutic modalities. Our findings suggest that SRS alone may be a viable therapeutic option for patients with incidentally-discovered NSCLC brain metastases.

Clinical and pathological characteristics of brain metastasis resected after failed radiosurgery

OBJECTIVE

This study evaluates the tumor histopathology and clinical characteristics of patients who underwent resection of their brain metastasis after failed gamma knife radiosurgery.

METHODS

This study was a retrospective review from a prospective database. A total of 1200 brain metastases in 912 patients were treated by gamma knife radiosurgery during a 7-year period. Fifteen patients (1.6% of patients, 1.2% of all brain metastases) underwent resective surgery for either presumed tumor progression (6 patients) or worsening neurological symptoms associated with increased mass effect (9 patients). Radiographic imaging, radiosurgical and surgical treatment parameters, histopathological findings, and long-term outcomes were reviewed for all patients.

RESULTS

The mean age at the time of radiosurgery was 57 years (age range, 32-65 years). Initial pathological diagnoses included metastatic non-small cell lung carcinoma in 8 patients (53%), melanoma in 4 patients (27%), renal cell carcinoma in 2 patients (13%), and squamous cell carcinoma of the tongue in 1 patient (7%). The mean time interval between radiosurgery and surgical extirpation was 8.5 months (range, 3 weeks to 34 months). The mean treatment volume for the resected lesion at the time of radiosurgery was 4.4 cm(3) (range, 0.6-8.4 cm(3)). The mean dose to the tumor margin was 21Gy (range, 18-24 Gy). In addition to the 15 tumors that were eventually resected, a total of 32 other metastases were treated synchronously, with a 78% control rate. The mean volume immediately before surgery for the 15 resected lesions was 7.5 cm(3) (range, 3.8-10.2 cm(3)). Histological findings after radiosurgery varied from case to case and included viable tumor, necrotic tumor, vascular hyalinization, hemosiderin-laden macrophages, reactive gliosis in surrounding brain tissue, and an elevated MIB-1 proliferation index in cases with viable tumor. The mean survival for patients in whom viable tumor was identified (9.4 months) was significantly lower than that of patients in whom only necrosis was seen (15.1 months; Fisher's exact test, P < 0.05).

CONCLUSION

Radiation necrosis and tumor radioresistance are the most common causes precipitating a need for surgical resection after radiosurgery in patients with brain metastasis.

Thirty years' experience with Gamma Knife surgery for metastases to the brain

Object

The aim of this study was to analyze factors influencing survival time and patterns of distant recurrences after Gamma Knife surgery (GKS) for metastases to the brain.

Methods

Information was available for 1855 of 1921 patients who underwent GKS for single or multiple cerebral metastases at 4 different institutions during different time periods between 1975 and 2007. The total number of Gamma Knife treatments administered was 2448, an average of 1.32 treatments per patient. The median survival time was analyzed, related to patient and treatment parameters, and compared with published data following conventional fractionated whole-brain irradiation.

Results

Twenty-five patients survived for longer than 10 years after GKS, and 23 are still alive. Age and primary tumor control were strongly related to survival time. Patients with single metastases had a longer survival than those with multiple metastases, but there was no difference in survival between patients with single and multiple metastases who had controlled primary disease. There were no significant differences in median survival time between patients with 2, 3–4, 5–8, or > 8 metastases. The 5-year survival rate was 6% for the whole patient population, and 9% for patients with controlled primary disease. New hematogenous spread was a more significant problem than micrometastases in patients with longer survival.

Conclusions

Patient age and primary tumor control are more important factors in predicting median survival time than number of metastases to the brain. Long-term survivors are more common than previously assumed.

Outcomes and cost-effectiveness of gamma knife radiosurgery and whole brain radiotherapy for multiple metastatic brain tumors

We aimed to analyze the outcomes and cost-effectiveness of gamma knife radiosurgery (GKRS) and whole brain radiotherapy (WBRT) for multiple metastatic brain tumors. Over a period of 5 years, 156 patients with multiple metastatic brain tumors were enrolled and freely assigned by the referring doctors to either gamma knife radiosurgery (GKRS, Group A, n=56), or to whole brain radiotherapy (WBRT, Group B, n=100). The follow-up time was set at 1200 days (3.3 years) post-treatment. The number of tumors, patient age, extent of systemic disease and Karnofsky performance scale (KPS) score, were recorded and recursive partitioning analysis used. The outcomes analyzed were: mortality, survival time, neurological complications, post-treatment KPS score, quality-adjusted life years (QALY), and cost-effectiveness. A paired t-test was used for statistical analysis. Mortality rates for patients receiving GKRS and WBRT were 81.1% and 93.0%, respectively (p=0.05). The mortality rate was lower for GKRS (74.4%) than for WBRT (97.1%) in patients with initial KPS70 (p=0.02). The mortality rate was also significantly lower for GKRS (78.9%) than WBRT (95.5%) in patients with 2-5 tumors (p<0.05). Post-treatment KPS score (mean+/-standard deviation [s.d.] was higher for patients receiving GKRS (73.8+/-13.2) than for those receiving WBRT (45.5+/-26.0), p<0.01. The median survival time for GKRS and WBRT was 9.5 months and 8.3 months, respectively, p=0.72. The mean (+/- s.d.) QALY was 0.76+/-0.23 for GKRS and 0.59+/-0.18 for WBRT, respectively (p<0.05). The cost-effectiveness per unit of QALY was better for the GKRS treatment (US$10,381/QALY) than in the WBRT treatment (US$17,622/QALY), p<0.05. The cost-effectiveness per KPS score was also higher for the GKRS treatment (US$139/KPS score) than for WBRT (US$229/KPS score), p<0.01. Thus, the mortality rate for multiple metastatic brain tumors treated by GKRS is significantly better with a good initial KPS score and when the tumor number is 2-5. GKRS results in a better post-treatment KPS score, QALY, and higher cost-effectiveness than WBRT for treating multiple metastatic brain tumors.

Analysis of patients with oligometastases undergoing two or more curative-intent stereotactic radiotherapy courses

PURPOSE

A subset of patients treated with curative-intent stereotactic radiotherapy (RT) for limited metastases (defined as five lesions or fewer) develop local failure and/or a small number of new lesions. We hypothesized that these patients would remain amenable to curative-intent treatment with additional RT courses.

METHODS AND MATERIALS

Of 121 prospective patients with five lesions or fewer treated with stereotactic RT, 32 underwent additional RT courses for local failure (n = 9) and/or new lesions (n = 29). Ten patients underwent three or more courses of RT.

RESULTS

The treated local failures developed a median of 20 months after RT completion. For the new oligometastases, the interval between the first and second RT course was 1-71 months (median, 8). Of the 32 patients undergoing multiple courses of curative-intent RT, the 2-year overall survival and progression-free survival rate was 65% and 54%, respectively. The corresponding 4-year rates were 33% and 28%. Compared with the 89 patients who underwent one RT course, these patients experienced a trend toward improved overall survival (median, 32 vs. 21 months, p = 0.13) and significantly greater progression-free survival (median, 28 vs. 9 months, p = 0.008).

CONCLUSION

The results of our study have shown that patients fare well with respect to survival and disease control with aggressive RT for limited metastases, even after local failure and/or the development of new metastases. Although patients amenable to multiple courses of curative-intent RT are arguably selected for more indolent disease, our hypothesis-generating analysis supports the notion of aggressively treating limited metastases, which, in some patients, might be curable and/or represent a chronic disease state.

Radiosurgery in the treatment of brain metastases: critical review regarding complications

Stereotactic radiosurgery (SRS) has been described as an effective treatment option for brain metastases. In general, SRS has been indicated for the treatment of lesions smaller than 3 cm in maximum diameter and for lesions considered not surgically treatable, owing to the patient's clinical status or because the lesion was located in or near eloquent brain areas. In several studies, SRS has been associated with clinical and radiographic improvement of the lesions and has been compared with surgery as the modality of choice for brain metastases. Beyond the high rate of local disease control with SRS, the few complications that have been described occurred mainly in the acute post treatment period. Most publications have addressed the outcome and effectiveness of this treatment modality but have not critically analyzed long-term complications, steroid dependency, or results relating to specific brain locations. It is important to understand the radiobiologic effects of a well-demarcated high dose of radiation on the brain lesion, controlling the tumor growth and not causing significant alteration of the related brain region, especially in an area controlling eloquent function.

Volumetric follow up of brain metastases: a useful method to evaluate treatment outcome and predict survival after Gamma Knife surgery?

Object

Brain metastases are diagnosed in 20 to 40% of all cancer patients and are associated with a considerable drop in life expectancy and often also in quality of life for these patients. Several treatment options are available including surgery, chemotherapy, whole-brain radiotherapy, stereotactic radiotherapy, stereotactic radiosurgery, and Gamma Knife surgery (GKS). However, management of brain metastases still presents a challenge and there is no general consensus on the best treatment strategy. The aim of the authors' study was to further evaluate the efficacy of GKS in the treatment of brain metastases and to evaluate the predictive value of volumetric tumor follow-up measurement.

Methods

Consecutive patients with controlled systemic cancer and variable numbers of brain metastases were included in this prospective study. Patients with severe symptoms of brain compression underwent surgery before GKS. Each follow-up examination included a thorough neurological examination and a neuroradiological quantitative volumetric tumor analysis.

A total of 300 consecutive patients (mean age 58 years) with 703 brain metastases were treated between December 1998 and October 2005. The mean total tumor volume (TTV) was 2.1 cm3. The overall local tumor control rate was 84.5%. In 79% of all treated metastases a mean TTV reduction of 84.7% was achieved using a mean prescription dose of 21.8 Gy. Only few, mostly mild, side effects were observed during the mean follow-up period of 12.7 months. The overall mean progression-free survival period was 9.4 months. There was a statistically significant difference in survival of patients with one compared with multiple metastases, regardless of the histological type and preceding treatment.

Conclusions

Gamma Knife surgery is a safe and effective treatment for patients with brain metastases regardless of the history of treatment and histological tumor type. It achieves excellent tumor control, significant TTV reduction without causing severe side effects, and accordingly, preserves quality of live. Volume changes after GKS did not serve as a predictor for treatment outcome and survival.

Current treatment paradigms for the management of patients with brain metastases

Brain metastases continue to be a major and growing challenge in oncology, but recent advances in surgery, radiosurgery, and chemotherapy have broadened the number of treatment options. Current approaches to the management of brain metastases focus on individualizing patient care based on factors including the Karnofsky Performance Status, the tumor histology, the number of metastases, and the status of the systemic disease. A number of treatment approaches have been shown to be effective for brain metastases, including surgery; radiosurgery; whole-brain radiotherapy; and, more recently, chemotherapy. The use of adjuvant whole-brain radiotherapy with local therapies, such as surgery or radiosurgery, along with newer chemotherapy options, such as targeted biological agents, temozolomide, and implantable 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) Gliadel wafers, are at the forefront of recent advances in the treatment of patients with brain metastases that may provide longer survival and improved quality of life. Although there is no current standard treatment, some general guidelines are recommended for single metastases, oligometastases (two to three brain metastases), and multiple (four or more) brain metastases, and for new or recurrent disease. With advances in systemic therapy for cancer, the treatment of brain metastases is becoming an increasingly important determinant of the length of survival and quality of life for cancer patients.

Radiosurgery in Metastatic Brain Cancer

Radiosurgery offers patients with brain metastases an effective and minimally invasive treatment modality. Radiosurgery provides local tumor control and prolongs survival in select patients with brain metastases. This review will discuss numerous aspects of radiosurgery, including the various delivery techniques and radiobiology. Treatment recommendations will be outlined in view of the available clinical data. Although surgery or radiosurgery with whole-brain radiotherapy remains an important option for patients with a solitary brain metastasis, radiosurgery with or without whole-brain radiotherapy should be considered in patients with a limited number of small tumors and a good prognosis.

Role of stereotactic radiosurgery as a primary treatment option in the management of newly diagnosed multiple (3-6) intracranial metastases

OBJECTIVE

The objective of this study was to assess the role of stereotactic radiosurgery in the management of newly diagnosed multiple intracranial metastases from known primary cancer locations.

METHODS

Fifty (29 women and 21 men) patients received radiosurgery for newly diagnosed 3 or more metastatic brain tumors. Their mean age was 53 years. Lung cancer was the most common primary cancer (66%).

RESULTS

Arrest in the growth of irradiated tumors was achieved in 41 (82%) patients. Eight patients (16%) required further intervention for tumors in other brain locations. Mean survival after diagnosis of brain disease was 12 months and the brain disease-controlled period was 19 months. The period of brain disease control prolonged (P=.03) with decreasing tumor volumes (<10 mL). Control of treated tumors positively affected survival after diagnosis of brain disease (P=.0001).

CONCLUSION

Radiosurgery as an adjuvant improves survival in patients with cancer who have newly diagnosed multiple intracranial metastases by arresting the growth of tumors.