Cumulative Intracranial Tumor Volume and Number of Brain Metastasis as Predictors of Developing New Lesions After Stereotactic Radiosurgery for Brain Metastasis

Stereotactic Radiosurgery as Treatment for Brain Metastases: An Update

Stereotactic radiosurgery (SRS) is a mainstay treatment option for brain metastasis (BM). While guidelines for SRS use have been outlined by professional societies, consideration of these guidelines should be weighed in the context of emerging literature, novel technology platforms, and contemporary treatment paradigms. Here, we review recent advances in prognostic scale development for SRS-treated BM patients and survival outcomes as a function of the number of BM and cumulative intracranial tumor volume. Focus is placed on the role of stereotactic laser thermal ablation in the management of BM that recur after SRS and the management of radiation necrosis. Neoadjuvant SRS prior to surgical resection as a means of minimizing leptomeningeal spread is also discussed.

Could intracranial tumor volume predict prognosis of patients with brain metastases from esophageal carcinoma?

PURPOSE

A previous study demonstrated that intracranial tumor volume had some correlation with gastrointestinal cancer patients' outcome. The aim of this study was to analyze patients with esophageal carcinoma (EC) and brain metastases to investigate if intracranial tumor volume would be a predictor of these patients' survival.

METHODS

A total of 52 patients with brain metastases from esophageal squamous cell carcinoma or esophageal adenocarcinoma were retrospectively reviewed. Patients without images of brain metastases in the hospital information system were eliminated.

RESULTS

The median follow-up time duration was 8.4 months (interquartile range 4.0-15.2). The median overall survival (OS) from time of brain metastases diagnosis was 8.0 months for all cases. Median OS of patients with small and large cumulative intracranial tumor volume (CITV) (<6.65 cm³ , ≥6.65 cm³ ) was 11.23 and 7.4 months, respectively. Median OS of patients with large and small largest intracranial tumor volume (LITV) (≥7.75 cm³ , <7.75 cm³ ) was 6.4 and 10.6 months, respectively. Univariate analysis demonstrated that CITV (hazard ratio [HR] 1.255, 95% confidence interval [CI] 0.673-2.342, p = 0.475) or LITV (HR 1.037, 95% CI 0.570-1.887, p = 0.904) was not significantly associated with improved OS. Multivariate analysis demonstrated that CITV and LITV were not significantly associated with improved OS.

CONCLUSION

EC patients with small intracranial tumor volume may have longer OS than those with large intracranial tumor volume, but this difference did not reach statistical difference. Future studies with a larger sample size may validate the correlation of intracranial tumor volume and patient survival.

An integrated disease-specific graded prognostic assessment scale for melanoma: contributions of KPS, CITV, number of metastases, and BRAF mutation status

Background

Stereotactic radiosurgery (SRS) remains a mainstay therapy in the treatment of melanoma brain metastases (BM). While prognostic scales have been developed for melanoma patients who underwent SRS treatment for BM, the pertinence of these scales in the context of molecularly targeted therapies remains unclear.

Methods

Through a multi-institutional collaboration, we collated the survival patterns of 331 melanoma BM patients with known BRAF mutation status treated with SRS. We established a prognostic scale that was validated in an independent cohort of 174 patients. All patients with BRAF mutations in this series were treated with BRAF inhibitors. Prognostic utility was assessed using Net Reclassification Index (NRI > 0) and integrated discrimination improvement (IDI) metrics.

Results

In a multivariate Cox proportional hazards model, BRAF mutation status, KPS, number of metastases, and cumulative intracranial tumor volume (CITV) independently contributed to survival prognostication for melanoma patients with SRS-treated BM (P < .05 for all variables). These variables were incorporated into a prognostic scale using the disease-specific graded prognostic assessment (ds-GPA) framework. This integrated melanoma ds-GPA scale was validated in 2 independent cohorts collated through a multi-institutional collaboration. In terms of order of prognostic importance, BRAF mutation status exerted the greatest influence on survival, while KPS, the number of metastases, and CITV exhibited comparable, lesser impacts.

Conclusions

Optimal survival prognostication for SRS-treated patients with melanoma BM requires an integrated assessment of patient characteristics (KPS), tumor characteristics (CITV and number of metastases), and the mutational profile of the melanoma (BRAF mutation status).

Bilateral occipital metastases: Visual deficits and management considerations

Background

Metastases to the bilateral occipital lobes pose a difficult clinical scenario due to risk of debilitating visual loss. We sought to characterize clinical outcomes following different treatment modalities to help guide management in this challenging situation.

Methods

We retrospectively reviewed brain metastases patients treated at a single institution between 2008 and 2017 and assessed visual symptoms before and after treatment, the tumor and peritumoral edema volumes before treatment, and clinical outcomes including mortality.

Results

Eighteen patients with metastases affecting both occipital lobes were identified. Lung cancer represented the most common primary (n = 10). Visual deficits were present in 12 patients at the time of diagnosis of bilateral occipital metastases (67%). Patients received radiotherapy (n = 5) or combined surgical resection and radiotherapy (n = 13). Among symptomatic patients, two received radiation and 10 received combined surgery and radiation. Nine patients had improved visual symptoms after treatment with no new visual deficits reported as a result of treatment. Among asymptomatic patients, three were treated with radiation alone and three with resection and radiation. Three of these patients developed new visual symptoms following treatment, including one patient with Balint's syndrome.

Conclusion

Patients with symptomatic bilateral occipital lobe metastases may experience visual improvement following intervention, especially if symptoms stem from compression or edema. Those without visual symptoms are at risk of developing new visual deficits during treatment, which should be included in the decision-making process and when counseling patients. Visual deficits improved after surgery in the majority of patients, with no cases of immediate visual deterioration.

Outcomes and prognostic stratification of patients with recurrent glioblastoma treated with salvage stereotactic radiosurgery

OBJECTIVE

Glioblastoma (GBM) is the most malignant form of astrocytoma. The average survival is 6-10 months in patients with recurrent GBM (rGBM). In this study, the authors evaluated the role of stereotactic radiosurgery (SRS) in patients with rGBMs.

METHODS

The authors performed a retrospective review of their brain tumor database (1997-2016). Overall survival (OS) and progression-free survival (PFS) after salvage SRS were the primary endpoints evaluated. Response to SRS was assessed using volumetric MR images.

RESULTS

Fifty-three patients with rGBM underwent salvage SRS targeting 75 lesions. The median tumor diameter and volume were 2.55 cm and 3.80 cm3, respectively. The median prescription dose was 18 Gy (range 12-24 Gy) and the homogeneity index was 1.90 (range 1.11-2.02). The median OS after salvage SRS was estimated to be 11.0 months (95% CI 7.1-12.2) and the median PFS after salvage SRS was 4.4 months (95% CI 3.7-5.0). A Karnofsky Performance Scale score ≥ 80 was independently associated with longer OS, while small tumor volume (< 15 cm3) and less homogeneous treatment plans (homogeneity index > 1.75) were both independently associated with longer OS (p = 0.007 and 0.03) and PFS (p = 0.01 and 0.002, respectively). Based on these factors, 2 prognostic groups were identified for PFS (5.4 vs 3.2 months), while 3 were identified for OS (median OS of 15.2 vs 10.5 vs 5.2 months).

CONCLUSIONS

SRS is associated with longer OS and/or PFS in patients with good performance status, small-volume tumor recurrences, and heterogeneous treatment plans. The authors propose a prognostic model to identify a cohort of rGBM patients who may benefit from SRS.

Pathologic Correlation of Cellular Imaging Using Apparent Diffusion Coefficient Quantification in Patients with Brain Metastases After Gamma Knife Radiosurgery

OBJECTIVE

To evaluate the role of apparent diffusion coefficient (ADC) in differentiating radiation necrosis (RN) from recurrent tumor after Gamma Knife radiosurgery (GKRS) for brain metastases (BMs).

METHODS

Forty-one patients with BM who underwent surgical intervention after GKRS at Cleveland Clinic (2006-2017) were included in this retrospective study. The ADC values of the growing lesions and the contralateral hemisphere were calculated using picture archiving and communication system. These values were correlated to the percentage of RN identified on pathologic evaluation of the surgical specimen.

RESULTS

The median age of the patients was 59 years (range, 25-86 years), and lung cancer (63.4%) was the most common malignancy. Median initial (pre-GKRS) target volume of the lesions was 5.4 cc (range, 0.135-45.6 cc), and median GKRS dose was 18.0 Gy. Surgical resection or biopsy was performed at a median of 176 days after GKRS. Two variables were statistically significant predictors of predominate RN (75%-100%) in the surgical specimen: 1) ADC of the lesion on the preresection magnetic resonance imaging (MRI) and 2) initial pre-GKRS target volume. ADC >1.5 × 10^-3 mm²/s within the lesion on MRI predicted significant RN on pathologic evaluation of the lesion (P < 0.05). Similarly, when the target volume before GKRS was large (>10 cc), the risk of identifying significant necrosis in the pathologic specimen was elevated (P < 0.05).

CONCLUSIONS

Our data suggest that the combination of lesion ADC on MRI prior to surgical intervention and the initial target volume can predict RN with reasonable accuracy.

Cognitive functioning and predictors thereof in patients with 1-10 brain metastases selected for stereotactic radiosurgery

PURPOSE

Information on predictive factors of cognitive functioning in patients with (multiple) brain metastases (BM) selected for radiosurgery may allow for more individual care and may play a role in predicting cognitive outcome after radiosurgery. The aim of this study was to evaluate cognitive performance, and predictors thereof, in patients with 1-10 BM before radiosurgery.

METHODS

Cognition was measured before radiosurgery using a standardized neuropsychological test battery in patients with 1-10 BM (expected survival > 3 months; KPS ≥ 70; no prior BM treatment). Regression formulae were constructed to calculate sociodemographically corrected z scores. Group and individual cognitive functioning was analyzed. Multivariable regression was used to explore potential predictors.

RESULTS

Patients (N = 92) performed significantly worse than controls (N = 104) on all 11 test variables (medium-large effect sizes for 8 variables). Percentages of impairment were highest for information processing (55.3%), dexterity (43.2%) and cognitive flexibility (28.7%). 62% and 46% of patients had impairments in at least two, or three test variables, respectively. Models including combinations of clinical and psychological variables were predictive of verbal memory, psychomotor speed, information processing and dexterity. Neither number nor volume of metastases predicted patients' test performance.

CONCLUSIONS

Already before radiosurgery, almost half of the patients suffered from severe cognitive deficits in at least three test variables. At group and individual level, information processing, cognitive flexibility, and dexterity were most affected. These cognitive impairments may impair daily functioning and patients' ability to make (shared) treatment decisions. Both clinical (symptomatic BM; timing of BM diagnosis) and psychological (mental fatigue) characteristics influenced cognitive performance.

CLINICAL TRIAL INFORMATION

Cognition and Radiation Study A (CAR-Study A; ClinicalTrials.gov Identifier: NCT02953756; Medical Ethics Committee file number: NL53472.028.15/P1515).

Patterns of Treatment and Outcome in Patients With 20 or More Brain Metastases

BACKGROUND/AIM

The aim of this study was to analyze the patterns of treatment and outcomes in patients with a large number of brain metastases, arbitrarily defined as 20 or more lesions. These patients are typically excluded from studies of focal brain treatment, e.g., surgery or radiosurgery, and might have a limited prognosis.

PATIENTS AND METHODS

This was a retrospective single-institution analysis. Overall, 11 patients were identified from a prospectively maintained database.

RESULTS

Ten patients had received active treatment (9 whole-brain radiotherapy, 7 systemic therapy). Median survival was 5.0 months without long-term survival beyond 13 months. Patients with better performance status had numerically longer survival, however we did not identify baseline parameters with a significant impact on survival.

CONCLUSION

While long-term survival was not observed in this small study, most patients survived long enough to experience symptomatic improvement from whole-brain radiotherapy. Therefore, we recommend multidisciplinary assessment of the patients' prognosis and systemic treatment options, and initiation of whole-brain radiotherapy if survival is not limited to 1-2 months.

Long-Term Outcome Following Stereotactic Radiosurgery for Glomus Jugulare Tumors: A Single Institution Experience of 20 Years

BACKGROUND

Glomus jugulare tumors (GJTs) are rare benign tumors, which pose significant treatment challenges due to proximity to critical structures.

OBJECTIVE

To evaluate the long-term clinical and radiological outcome in patients undergoing stereotactic radiosurgery (SRS) for GJTs through retrospective study.

METHODS

Forty-two patients with 43 GJTs were treated using Gamma Knife radiosurgery (GKRS; Elekta AB, Stockholm, Sweden) at our institute from 1997 to 2016. Clinical, imaging, and radiosurgery data were collected from an institutional review board approved database.

RESULTS

Most patients were females (n = 35, 83.3%) and median age was 61 yr (range 23-88 yr). Median tumor volume and diameter were 5 cc and 3 cm, respectively, with a median follow-up of 62.3 mo (3.4-218.6 mo). Overall, 20 patients (47.6%) improved clinically and 14 (33.3%) remained unchanged at last follow-up. New onset or worsening of hearing loss was noted in 6 patients (17.2%) after SRS. The median prescription dose to the tumor margin was 15 Gy (12-18 Gy). Median reduction in tumor volume and maximum tumor diameter at last follow-up was 33.3% and 11.54%, respectively. The 5-yr and 10-yr tumor control rates were 87% ± 6% and 69% ± 13%, respectively. There was no correlation between maximum or mean dose to the internal acoustic canal and post-GK hearing loss (P > .05).

CONCLUSION

SRS is safe and effective in patients with GJTs and results in durable, long-term control. SRS has lower morbidity than that associated with surgical resection, particularly lower cranial nerve dysfunction, and can be a first-line management option in these patients.

Radiological Kinetics of Brain Metastases and Clinical Implications for Patients Treated With Stereotactic Radiosurgery

AIMS

Select patients with brain metastases receive stereotactic radiosurgery (SRS) with the objective of improving survival and intracranial disease control. Brain metastases number and volume are prognostic factors used to inform patient selection. The aim of this study was to assess the rate of change of brain metastases size and number (growth kinetics) between the diagnostic and day of SRS magnetic resonance imaging (MRI) scans.

MATERIALS AND METHODS

All patients treated with Gamma Knife SRS between October 2015 and April 2017 were included in this single-centre retrospective analysis. Brain metastases number and diameter were recorded at diagnosis and treatment. For patients with multiple brain metastases, the largest lesion was the index lesion. Distant intracranial control and overall survival were reported from the date of SRS.

RESULTS

In total, 146 patients received 156 episodes of SRS. The median interval between diagnostic and SRS MRI was 20 days (range 1-68). Interval growth in the index lesion of at least 3 mm or the development of a new brain metastasis was noted in 60.2% of patients. This was associated with age less than 60 years (P = 0.001), Eastern Cooperative Oncology Group (ECOG) performance status 2 or above (P = 0.04), non-small cell lung carcinoma (NSCLC) (P = 0.03) or melanoma histologies (P = 0.05) and uncontrolled extracranial disease (P = 0.05). These patients were also more likely to develop distant intracranial recurrence (P = 0.046). Clinically significant growth was not associated with scan interval or differences in overall survival. The Kaplan-Meier estimate of probability of survival at 12 months was 59.3% (95% confidence interval 46.7-75.2%) for all patients.

CONCLUSION

Intracranial progression between diagnosis and day of SRS is common. Risk factors are uncontrolled extracranial disease, poorer performance status, NSCLC or melanoma histologies and age less than 60 years. These patients would benefit from an MRI closer to treatment to inform patient selection and target delineation for SRS planning.