Brain metastases from renal cell carcinoma: Effects of novel systemic agents on brain metastasis outcomes.

OBJECTIVE: The objective of this study was to examine survival outcomes in 136 patients with renal cell carcinoma with metastases to the brain who were treated with radiation combined with immunotherapy or tyrosine kinase inhibitor compared to those who were treated with radiation therapy alone. METHODS: The Wake Forest Gamma Knife prospective database was searched for all patients with renal cell carcinoma brain metastases. Outcome measurements included overall survival, determined via the Kaplan-Meier Method, and cumulative incidence of local and distant failure, determined using the Fine Gray competing risks analysis with death as a competing risk for the 136 patients included. RESULTS: Overall survival for the entire population at 6 months, 12 months, and 24 months was 67%, 47% and 30%, respectively. For the TKI (non-immunotherapy-treated) population (n = 37), overall survival was 75%, 61%, and 40% at 6 months, 12 months, and 24 months, respectively. For the immunotherapy-treated population (n = 35), overall survival was 85%, 64%, and 50% at 6 months, 12 months, and 24 months, respectively. Overall survival was significantly increased for patients who received radiation with either immunotherapy or TKI (p < 0.0001). CONCLUSION: Prior series of patients with brain metastases of multiple histologies have demonstrated an improvement in the local efficacy of stereotactic radiosurgery when combined with systemic agents. We found that patients treated with targeted agents and patients treated with immunotherapy demonstrated a trend towards improvement over patients treated in the era prior to the advent of either classes of novel therapies.

Delayed Imaging Changes 18 Months or Longer After Stereotactic Radiosurgery for Brain Metastases: Necrosis or Progression.

OBJECTIVE: Imaging changes after stereotactic radiosurgery (SRS) can occur for years after treatment, although the available data on the incidence of tumor progression and adverse radiation effects (ARE) are generally limited to the first 2 years after treatment. METHODS: A single-institution retrospective review was conducted of patients who had >18 months of imaging follow-up available. Patients who had ≥1 metastatic brain lesions treated with Gamma Knife SRS were assessed for the time to radiographic progression. Those with progression ≥18 months after the initial treatment were included in the present study. The lesions that progressed were characterized as either ARE or tumor progression based on the tissue diagnosis or imaging characteristics over time. RESULTS: The cumulative incidence of delayed imaging radiographic progression was 35% at 5 years after the initial SRS. The cumulative incidence curves of the time to radiographic progression for lesions determined to be ARE and lesions determined to be tumor progression were not significantly different statistically. The cumulative incidence of delayed ARE and delayed tumor progression was 17% and 16% at 5 years, respectively. Multivariate analysis indicated that the number of metastatic brain lesions present at the initial SRS was the only factor associated with late radiographic progression. CONCLUSIONS: The timing of late radiographic progression does not differ between ARE and tumor progression. The number of metastatic brain lesions at the initial SRS is a risk factor for late radiographic progression.

Low contralateral neck recurrence risk with ipsilateral neck radiotherapy in N2b tonsillar squamous cell carcinoma.

OBJECTIVES: To characterize factors including nodal burden, pre-treatment imaging, and other patient factors which may influence the role of ipsilateral neck radiotherapy (IRT) in tonsillar squamous cell carcinoma (SCC) with multiple involved ipsilateral nodes. METHODS: Patients with cT1-2N0-2bM0 (AJCC 7th edition) tonsillar SCC treated with definitive radiation therapy (RT) at Duke University Medical Center from 1/1/1990-10/1/2019 were identified. Patient, tumor, and treatment characteristics were compared between those that received bilateral neck RT (BRT) versus IRT. Recurrence-free survival (RFS) was estimated with Kaplan-Meier method. A subset analysis of patients with N2b disease was performed. Patterns of recurrence were analyzed. RESULTS: 120 patients with cT1-2N0-2b tonsillar SCC were identified, including 71 with N2b disease (BRT: n = 30; IRT: n = 41). Median follow-up was 80 months (range: 7-209). No N2b patients who received IRT had > 1 cm of soft palate/base of tongue extension. N2b patients treated with IRT had a median of 3 (range 2-9) involved lymph nodes, with median largest nodal dimension of 2.8 cm (range 1.3-4.8 cm). 93 % of N2b patients who received IRT had staging by PET/CT, and 100 % received IMRT. For N2b patients treated with IRT, there were no contralateral neck recurrences, and 10 year RFS was 95 % (95 % CI 82 %-98 %). CONCLUSIONS: For patients treated with IRT for well-lateralized N2b tonsillar SCC, we observed high rates of local control with no observed contralateral neck recurrence. These data suggest that BRT is not universally necessary for patients with multiple involved ipsilateral nodes, particularly in the setting of baseline staging with PET/CT.

Five-year survivors from brain metastases treated with stereotactic radiosurgery: Biology, improving treatments, or just plain luck?

Background: Improvements in therapies have led to an increasing number of long-term survivors of brain metastases. The present series compares a population of 5-year survivors of brain metastases to a generalized brain metastases population to assess for factors attributable to long-term survival. Methods: A single institution retrospective review was performed to identify 5-year survivors of brain metastases who received stereotactic radiosurgery (SRS). A historical control population of 737 patients with brain metastases was used to assess similarities and differences between the long-term survivor population and the general population treated with SRS. Results: A total of 98 patients with brain metastases were found to have survived over 60 months. No differences between long-term survivors and controls were identified with regards to the age at first SRS (P = .19), primary cancer distribution (P = .80), and the number of metastases at first SRS (P = .90). Cumulative incidence of neurologic death at 6, 8 and 10 years for the long-term survivor cohort was 4.8%, 16%, and 16% respectively. In the historical controls, cumulative incidence of neurologic death reached a plateau at 40% after 4.9 years. A significant difference in the distribution of burden of disease at the time of the first SRS was found between the 5-year survivors and the control (P = .0049). 58% of 5-year survivors showed no evidence of clinical disease at the last follow-up. Conclusion: Five-year survivors of brain metastases represent a diverse histologic population, suggesting a small population of oligometastatic and indolent cancers exist for each cancer type.

Outcomes of radiation-induced meningiomas treated with stereotactic radiosurgery.

PURPOSE: Data on the efficacy and safety of stereotactic radiosurgery (SRS) for treatment of radiation-induced meningiomas (RIMs) are limited. METHODS: A single institution database of Cobalt-60 SRS cases from 08/1999 to 10/2020 was reviewed. Radiation-induced meningiomas were identified using Cahan's criteria. Endpoints included overall survival (OS), progression free survival (PFS), local control (LC), treatment failure, and treatment toxicity. Univariate and multivariate analyses were performed using cox proportional hazard models. RESULTS: A total of 29 patients with 86 RIM lesions were identified. Median follow-up after SRS was 59 months. The median dose prescribed to the 50% isodose line was 14 Gy (range 12-20 Gy). The actuarial 5-yr OS and PFS were 96% and 68%, respectively. Patients treated for recurrent RIMs had a significantly lower PFS (45% vs 94% at 3 yr, p < 0.005) than patients treated in the upfront setting. Patients with presumed or WHO grade I RIMs had a significantly greater PFS (3-year PFS 96% vs 20%) than patients with WHO grade II RIMs (p < 0.005). On a per-lesion basis, local control (LC) at 1-, 3-, and 5-yrs was 82%, 76%, 74%, respectively. On multivariate analysis, female gender was associated with improved LC (p < 0.001), while marginal doses > 14 Gy were associated with worse local control (p < 0.001). Grade I-III toxicity following treatment was 9.0%. CONCLUSIONS: Stereotactic radiosurgery is a safe and effective treatment option for radiographic RIMs, WHO grade I RIMs, or lesions treated in the upfront setting. WHO grade II lesions and recurrent lesions are at increased risk for disease progression.

Long term survivors of stereotactic radiosurgery for brain metastases: do distant brain failures reach a plateau and what factors are associated with a brain metastasis velocity of zero?

PURPOSE: Life expectancy continues to increase for patients with brain metastases treated with stereotactic radiosurgery (SRS). The present study sought to retrospectively analyze brain metastasis patients who have survived 2 years or more, and assess for what factors may predict for a final brain metastasis velocity (BMV) of zero. METHODS: This was a single-institution retrospective study of 300 patients treated with SRS from 2001 to 2019 for brain metastases who survived greater than 2 years after first SRS. Final BMV is calculated by summing all metastases through the observed time divided by the total time in years. A BMV of zero is defined as at least 2 years of imaging follow-up without distant brain failure (DBF). RESULTS: Median age at first SRS is 61 (IQR: 53, 70). Kaplan-Meier estimated median overall survival is 4.9 years and time to DBF is 1.5 years (95% CI 1.2, 2.0). Twenty-eight (9.3%) patients underwent subsequent WBRT. One hundred and one (33.7%) patients never had any further brain metastases (BMV = 0) at a median follow-up time of 3.3 years. Median BMV is 0.4 (IQR: 0, 1.4). Distant brain failures reach a plateau at 4 years where the cumulative incidence of DBF is 82%. 70% of first time DBFs have occurred by 2 years. Factors significantly associated with a BMV of zero include fewer brain metastases at first SRS (HR 1.1; p = 0.0004) and Caucasian race (HR 1.5; p = 0.03). CONCLUSION: Approximately one third of brain metastasis patients who live beyond 2 years after initial SRS have a BMV of zero. DBFs appear to reach a plateau at 4 years. Factors significantly associated with a BMV of zero include Caucasian race and having had a single brain metastasis at first SRS.

A transformer-based deep-learning approach for classifying brain metastases into primary organ sites using clinical whole-brain MRI images.

Treatment decisions for brain metastatic disease rely on knowledge of the primary organ site and are currently made with biopsy and histology. Here, we develop a deep-learning approach for accurate non-invasive digital histology with whole-brain magnetic resonance imaging (MRI) data. Contrast-enhanced T1-weighted and fast spoiled gradient echo brain MRI exams (n = 1,582) were preprocessed and input to the proposed deep-learning workflow for tumor segmentation, modality transfer, and primary site classification into one of five classes. Tenfold cross-validation generated an overall area under the receiver operating characteristic curve (AUC) of 0.878 (95% confidence interval [CI]: 0.873,0.883). These data establish that whole-brain imaging features are discriminative enough to allow accurate diagnosis of the primary organ site of malignancy. Our end-to-end deep radiomic approach has great potential for classifying metastatic tumor types from whole-brain MRI images. Further refinement may offer an invaluable clinical tool to expedite primary cancer site identification for precision treatment and improved outcomes.

Upfront immunotherapy leads to lower brain metastasis velocity in patients undergoing stereotactic radiosurgery for brain metastases.

Background: While immunotherapy has been shown to improve survival and decrease neurologic death in patients with brain metastases, it remains unclear whether this improvement is due to prevention of new metastasis to the brain. Method: We performed a retrospective review of patients presenting with brain metastases simultaneously with the first diagnosis of metastatic disease and were treated with upfront immunotherapy as part of their treatment regimen and stereotactic radiosurgery (SRS) to the brain metastases. We compared this cohort with a historical control population (prior to the immunotherapy era) who were treated with pre-immunotherapy standard of care systemic therapy and with SRS to the brain metastases. Results: Median overall survival time was improved in the patients receiving upfront immunotherapy compared to the historical cohort (48 months vs 8.4 months, p=0.001). Median time to distant brain failure was statistically equivalent (p=0.3) between the upfront immunotherapy cohort and historical control cohort (10.3 vs 12.6 months). Brain metastasis velocity was lower in the upfront immunotherapy cohort (median 3.72 metastases per year) than in the historical controls (median 9.48 metastases per year, p=0.001). Cumulative incidence of neurologic death at one year was 12% in the upfront immunotherapy cohort and 28% in the historical control cohort (p=0.1). Conclusions: Upfront immunotherapy appears to improve overall survival and decrease BMV compared to historical controls. While these data remain to be validated, they suggest that brain metastasis patients may benefit from concurrent immunotherapy with SRS.

Intensity-modulated radiotherapy with planned Gamma Knife radiosurgery boost for head and neck cancer with extensive disease in proximity to critical structures.

BACKGROUND: To describe intensity-modulated radiotherapy (IMRT) with Gamma Knife Radiosurgery (GKRS) boost for locally advanced head and neck cancer (HNC) with disease near dose-limiting structures. METHODS: Patients with HNC treated with IMRT/GKRS as part of a combined modality approach between 2011 and 2021 were reviewed. Local control, overall survival and disease-specific survival were estimated using the Kaplan Meier method. RESULTS: Twenty patients were included. Nineteen patients had T3-4 tumors. Median follow-up was 26.3 months. GKRS site control was 95%. Two patients progressed at the treated primary site, one patient failed at the edge of the GKRS treatment volume, with no perineural or intracranial failure. 2-year OS was 94.7% (95% CI: 85.2%-100%). Concurrent chemotherapy was given in nine patients (45%). One patient (5%) received induction/concurrent chemotherapy. Brain radionecrosis occurred in three patients, one of which was biopsy-proven. CONCLUSIONS: IMRT plus GKRS boost results in excellent disease control near critical structures with minimal toxicity.

Clinical outcomes of dose-escalated re-irradiation in patients with recurrent high-grade glioma.

Background: Re-irradiation for recurrent gliomas is a controversial treatment option with no clear standard dose or concurrent systemic therapy. Methods: This series represents a single-institution retrospective review of patients treated with re-irradiation for recurrent high-grade glioma. After 2012, patients were commonly offered concurrent bevacizumab as a cytoprotective agent against radiation necrosis. Kaplan-Meier method was used to estimate overall survival and progression-free survival. Cox proportional hazards regression was used to identify factors associated with overall survival and progression-free survival. Results: Between 2001 and 2021, 52 patients underwent re-irradiation for a diagnosis of recurrent high-grade glioma. 36 patients (69.2%) had a histologic diagnosis of glioblastoma at the time of re-irradiation. The median BED10 (biological equivalent dose 10 Gy) of re-irradiation was 53.1 Gy. Twenty-one patients (40.4%) received concurrent bevacizumab with re-irradiation. Median survival for the entire cohort and for glioblastoma at the time of recurrence patients was 6.7 months and 6.0 months, respectively. For patients with glioblastoma at the time of recurrence, completing re-irradiation (HR 0.03, P < .001), use of concurrent bevacizumab (HR 0.3, P = .009), and the BED10 (HR 0.9, P = .005) were predictive of overall survival. Nine patients developed grade 3-5 toxicity; of these, 2 received concurrent bevacizumab and 7 did not (P = .15). Conclusion: High dose re-irradiation with concurrent bevacizumab is feasible in patients with recurrent gliomas. Concurrent bevacizumab and increasing radiation dose may improve survival in patients with recurrent glioblastoma.

Local control outcomes for combination of stereotactic radiosurgery and immunotherapy for non-small cell lung cancer brain metastases.

BACKGROUND: Previous series have demonstrated CNS activity for immune checkpoint inhibitors, yet no prior data exists regarding whether this activity can improve outcomes of stereotactic radiosurgery. METHODS: In this single institution retrospective series, the clinical outcomes of 80 consecutive lung cancer patients treated with concurrent immune checkpoint inhibitors and stereotactic radiosurgery were compared to 235 in the historical control cohort in which patients were treated prior to immune checkpoint inhibition being standard upfront therapy. Overall survival was estimated using the Kaplan Meier method. Cumulative incidence of local progression was estimated using a competing risk model. RESULTS: Median overall survival time was improved in patients receiving upfront immunotherapy compared to the historical control group (40 months vs 8 months, p < 0.001). Factors affected overall survival include concurrent immunotherapy (HR 0.23, p < 0.0001) and KPS (HR 0.97, p = 0.0001). Cumulative incidence of local failure in the historical control group was 10% at 1 year, compared to 1.1% at 1 year in the concurrent immunotherapy group (p = 0.025). Factors affected local control included use of concurrent immunotherapy (HR 0.09, p = 0.012), and lowest margin dose delivered to a metastasis (HR 0.8, p = 0.0018). CONCLUSION: Local control and overall survival were both improved in patients receiving concurrent immune checkpoint inhibitors with radiosurgery compared to historical controls. While these data remain to be validated, they suggest that brain metastasis patients may benefit from concurrent use of immunotherapy with SRS.

A Single-Institution Retrospective Study of Patients Treated With Laser-Interstitial Thermal Therapy for Radiation Necrosis of the Brain.

Object Laser-interstitial thermal therapy (LITT) has been proposed as an alternative treatment to surgery for radiation necrosis (RN) in patients treated with stereotactic radiosurgery (SRS) for brain metastases. The present study sought to retrospectively analyze LITT outcomes in patients with RN from SRS. Methods This was a single-institution retrospective study of 30 patients treated from 2011-2018 with pathologically-proven RN after SRS for brain metastases (n=28) or proximally treated extracranial lesions treated with external beam radiotherapy (n=2). Same-day biopsy was performed in all cases. Patients were prospectively followed with Functional Assessment of Cancer Therapy - Brain (FACT-Br), EuroQol-5 Dimension (EQ-5D), Hopkins Verbal Learning Test (HVLT) and clinical history and examination. Adjusted means, standard errors and tests comparing visits to pre-LITT were generated. Kaplan-Meier method was used to estimate time overall survival. Competing risk analysis was used to estimate cumulative incidence of LITT failure. Results In our patient population, median time from radiotherapy to LITT was 13.1 months. Median SRS dose and median LITT treatment target volume were 20 Gy (IQR 18-22) and 3.5 cc (IQR 2.2-4.6), respectively. Seventy-seven percent of our patients tapered off steroids within one month. There were only two instances of RN recurrence after LITT, with recurrence defined as recurrence of symptoms after initial improvement. These recurrences occurred at 1.9 and 3.4 months. The three-, six- and nine-month freedom from recurrence rates were 95.7%, 90.9%, and 90.9%. Median survival in our patient population with pathologically confirmed RN treated with LITT was 2.1 years. Regarding the quality of life questionnaires with which some patients were followed as part of different prospective studies, completion rates were 22/30 for FACT-Br, 16/30 for the EQ-5D and 8/30 for HVLT. Quality of life questionnaire results were overall stable from baseline. Mean FACT-Br scores were stable from baseline (17.9, 16.6, 21.4 and 22.8) to three months (18.8, 15.4, 18.4 and 23.4) (p=0.38, 0.53, 0.09 and 0.59). The mean EQ-5D Aggregate score was stable from baseline (7.1) to one month (7.6) (p=0.25). Mean HVLT-R Total Recall was stable from baseline (20.6) to three months (18.4) (p=0.09). There was a statistically significant decrease in mean Karnofsky Performance Scale (KPS) score from baseline (84) to three-month follow-up (75) (p=0.03). Conclusions LITT represents a safe and durably effective treatment option for RN in the brain. Results demonstrate a median survival of 2.1 years from LITT with only two recurrences, both within four months of treatment and salvageable. Patient-reported outcomes showed no severe declines after LITT. Quality of life questionnaires demonstrated stable well-being and functionality from baseline. LITT should be considered for definitive treatment of RN, especially in cases where patients have significant side effects from standards medical therapies such as steroids or if steroids are minimally effective.

Stereotactic Radiosurgery for Atypical and Anaplastic Meningiomas.

BACKGROUND: Although most meningiomas will be benign, a small proportion will have atypical or anaplastic histologic features and will exhibit more aggressive behavior. The treatment of these tumors has been controversial, especially for patients with recurrence after resection and radiotherapy. We have presented a large series of atypical and anaplastic meningiomas treated with stereotactic radiosurgery (SRS). METHODS: We performed a retrospective review of a single-institution radiosurgery database and identified 48 patients with 183 lesions who had undergone 99 SRS sessions from 1999 to 2019. The median dose was 15 Gy prescribed to the 50% isodose line. The center of the failures was plotted, and the distance from the treated tumor to the center of the failure was measured. Simulated treatment volumes for external beam radiotherapy were generated according to the target, and failures were characterized as local, marginal, or distant according to the simulated volume. RESULTS: The 5-year disease-free and overall survival rate measured from the initial SRS session was 45.8% and 74.7%, respectively. The 5-year lesional control rate was 68.9%. The most common pattern of first failure was isolated distant failure, followed by isolated local or marginal failure. The incidence of distant failure was significantly greater after treatment of >2 lesions in a single SRS session. Isolated local/marginal failure was associated with grade III tumors and an increasing tumor size. CONCLUSIONS: High-risk meningiomas are a heterogeneous group of tumors with a propensity for multiple failures. The most common pattern of relapse after SRS was distant. However, local control remains an issue. Further studies evaluating dose-escalation strategies are warranted.

Predictors of Adverse Radiation Effect in Brain Metastasis Patients Treated With Stereotactic Radiosurgery and Immune Checkpoint Inhibitor Therapy.

PURPOSE: Immune checkpoint inhibitor (ICI) therapy has recently been found to improve survival in patients with a number of cancers, including those with metastatic disease. There is an association of adverse radiation effect (ARE) in patients with brain metastases who have been treated with stereotactic radiosurgery (SRS) and ICIs. METHODS AND MATERIALS: Single-institution retrospective review identified 1118 brain metastases treated with SRS between 2013 and 2018 that had received ICI therapy and 886 metastases that did not receive ICI. Toxicity grading was done via the Common Terminology Criteria for Adverse Events v4.0 grading criteria. Cumulative incidence of ARE was estimated using competing risks methodology; univariate and multivariable regression models were generated to estimate the subdistribution hazard (sHR) of ARE. RESULTS: Two-year cumulative incidence of ARE was 4.5% and 2.1% in patients treated with and without ICI, respectively (Gray's P = .004). Of the 52 metastases exhibiting ARE during the follow-up period, ARE severity by Common Terminology Criteria for Adverse Events v4 was grade 1 in 14 patients, grade 2 in 15, grade 3 in 9, and grade 4 in 14. There were no grade 5 events. Factors associated with an increased sHR of ARE on univariate analysis included ICI, metastasis volume, SRS dose, prescription isodose line, cavity-directed SRS, and V12. Multivariable analysis revealed prescription isodose line (sHR 0.95, P < .01) and ICI (sHR 2.58, P < .01) as significant predictors of ARE. Increasing V12 was associated with a rapidly increasing risk of adverse radiation effect in patients who received ICI. CONCLUSIONS: Our findings suggest that patients receiving ICI have an increased risk of ARE after radiosurgery for brain metastases, with large metastases being at particularly high risk.

Results of a third Gamma Knife radiosurgery for trigeminal neuralgia.

OBJECTIVE: Gamma Knife radiosurgery (GKRS) is a commonly used procedure for medically refractory trigeminal neuralgia (TN), with repeat GKRS routinely done in cases of pain relapse. The results of a third GKRS in cases of further pain relapse have not been well described. In this study, the authors report the largest series of patients treated with a third GKRS for TN to date. METHODS: Retrospective review of institutional electronic medical records and a GKRS database was performed to identify patients who had been treated with a third GKRS at the authors' institution in the period from 2010 to 2018. Telephone interviews were used to collect long-term follow-up data. Pain outcomes were measured using the Barrow Neurological Institute (BNI) pain intensity scale, with a score ≤ IIIb indicating successful treatment. RESULTS: Twenty-two nerves in 21 patients had sufficient follow-up to determine BNI pain score outcomes. Eighteen of 22 cases had a successful third GKRS, with a median durability of pain relief of 3.88 years. There was no significant difference in the durability of pain relief after a third GKRS compared with those of institutional historical controls of prior series of first and second GKRS procedures. Ten cases had new or worsening facial numbness, with 1 case being bothersome. Four cases of toxicity other than facial numbness were reported, including 1 case of corneal abrasions and possible neurotrophic keratopathy. No cases of anesthesia dolorosa were reported. No factors predicting treatment success or the durability of pain relief were identified. Nonnumbness toxicity was more common in those with a proximally placed shot at the third GKRS. CONCLUSIONS: A third GKRS is an effective treatment option for TN patients who have pain relapse after repeat GKRS. Pain outcomes of a third GKRS are similar to those following a first or second GKRS. Toxicity is tolerable in patients with a distally placed shot at the third GKRS.

Impact of brain metastasis velocity on neurologic death for brain metastasis patients experiencing distant brain failure after initial stereotactic radiosurgery.

PURPOSE: Patients with high rates of developing new brain metastases have an increased likelihood of dying of neurologic death. It is unclear, however, whether this risk is affected by treatment choice following failure of primary stereotactic radiosurgery (SRS). METHODS: From July 2000 to March 2017, 440 patients with brain metastasis were treated with SRS and progressed to have a distant brain failure (DBF). Eighty-seven patients were treated within the immunotherapy era. Brain metastasis velocity (BMV) was calculated for each patient. In general, the institutional philosophy for use of salvage SRS vs whole brain radiotherapy (WBRT) was to postpone the use of WBRT for as long as possible and to treat with salvage SRS when feasible. No further treatment was reserved for patients with poor life expectancy and who were not expected to benefit from salvage treatment. RESULTS: Two hundred and eighty-five patients were treated with repeat SRS, 91 patients were treated with salvage WBRT, and 64 patients received no salvage radiation therapy. One-year cumulative incidence of neurologic death after salvage SRS vs WBRT was 15% vs 23% for the low- (p = 0.06), 30% vs 37% for the intermediate- (p < 0.01), and 31% vs 48% (p < 0.01) for the high-BMV group. Salvage WBRT was associated with increased incidence of neurologic death on multivariate analysis (HR 1.64, 95% CI 1.13-2.39, p = 0.01) when compared to repeat SRS. One-year cumulative incidence of neurologic death for patients treated within the immunotherapy era was 9%, 38%, and 38% for low-, intermediate-, and high-BMV groups, respectively (p = 0.01). CONCLUSION: Intermediate and high risk BMV groups are predictive of neurologic death. The association between BMV and neurologic death remains strong for patients treated within the immunotherapy era.

Multi-institutional validation of brain metastasis velocity, a recently defined predictor of outcomes following stereotactic radiosurgery.

INTRODUCTION: Brain metastasis velocity (BMV) is a prognostic metric that describes the recurrence rate of new brain metastases after initial treatment with radiosurgery (SRS). We have previously risk stratified patients into high, intermediate, and low-risk BMV groups, which correlates with overall survival (OS). We sought to externally validate BMV in a multi-institutional setting. METHODS: Patients from nine academic centers were treated with upfront SRS; the validation cohort consisted of data from eight institutions not previously used to define BMV. Patients were classified by BMV into low (<4 BMV), intermediate (4-13 BMV), and high-risk groups (>13 BMV). Time-to-event outcomes were estimated using the Kaplan-Meier method. Cox proportional hazards methods were used to estimate the effect of BMV and salvage modality on OS. RESULTS: Of 2829 patients, 2092 patients were included in the validation dataset. Of these, 921 (44.0%) experienced distant brain failure (DBF). Median OS from initial SRS was 11.2 mo. Median OS for BMV < 4, BMV 4-13, and BMV > 13 were 12.5 mo, 7.0 mo, and 4.6 mo (p < 0.0001). After multivariate regression modeling, melanoma histology (ß: 10.10, SE: 1.89, p < 0.0001) and number of initial brain metastases (ß: 1.52, SE: 0.34, p < 0.0001) remained predictive of BMV (adjusted R2 = 0.06). CONCLUSIONS: This multi-institutional dataset validates BMV as a predictor of OS following initial SRS. BMV is being utilized in upcoming multi-institutional randomized controlled trials as a stratification variable for salvage whole brain radiation versus salvage SRS after DBF.

Immunotherapy is associated with improved survival and decreased neurologic death after SRS for brain metastases from lung and melanoma primaries.

BACKGROUND: The effect of immunotherapy on brain metastasis patients remains incompletely understood. Our goal was to evaluate its effect on survival, neurologic death, and patterns of failure after stereotactic radiosurgery (SRS) without prior whole-brain radiation therapy (WBRT) in patients with lung and melanoma primaries metastatic to the brain. METHODS: We performed a retrospective analysis of 271 consecutive lung or melanoma patients treated with upfront SRS for brain metastases between 2013 and 2018. Of these patients, 101 (37%) received immunotherapy and 170 (63%) did not. Forty-three percent were treated with nivolumab. Thirty-seven percent were treated with pembrolizumab. Fifteen percent were treated with ipilimumab. One percent were treated with a combination of nivolumab and ipilimumab. One percent were treated with atezolizumab. Three percent were treated with another immunotherapy regimen. Survival was estimated by the Kaplan-Meier method and cumulative incidences of neurologic death, and local and distant brain failure were estimated using death as a competing risk. RESULTS: The median overall survival (OS) of patients treated with immunotherapy vs without was 15.9 (95% CI: 13.3 to 24.8) vs 6.1 (95% CI: 5.1 to 8.8) months (P < .01). The 1-year cumulative incidence of neurologic death was 9% in patients treated with immunotherapy vs 23% in those treated without (P = .01), while nonneurologic death was not significantly different (29% vs 41%, P = .51). Median brain metastasis velocity (BMV) did not differ between groups, and rates of salvage SRS and WBRT were similar. CONCLUSIONS: The use of immunotherapy in patients with lung cancer or melanoma metastatic to the brain treated with SRS is associated with improved OS and decreased incidence of neurologic death.

Cognitive functioning following brain irradiation as part of cancer treatment: Characterizing better cognitive performance.

OBJECTIVE: Although brain radiation therapy (RT) impacts cognitive function, little is known about the subset of survivors with minimal cognitive deficits. This study compares the characteristics of patients receiving brain irradiation as part of cancer treatment with minimal cognitive deficits to those with poorer cognitive functioning. METHODS: Adults at least 6 months postbrain RT (N = 198) completed cognitive measures of attention, memory, and executive functions. Cognitive functioning was categorized into better- and poorer-performing groups, with better-performing survivors scoring no worse than 1.5 standard deviations below the published normative mean on all cognitive measures. Logistic regression was used to identify variables associated with better-performing group membership. RESULTS: Approximately 25% of the sample met the criteria for the better-performing group. In unadjusted analyses, RT type (whole brain irradiation and partial brain irradiation), sedating medications, and fatigue were independently associated with cognition. Sociodemographic and other clinical characteristics were not significant. In adjusted analyses, only fatigue remained significantly associated with group membership (OR = 1.05, 95% CI = 1.01-1.09, P = .009). CONCLUSIONS: There is a subgroup of survivors with minimal long-term cognitive deficits despite undergoing a full course of brain RT as part of cancer treatment. Lower fatigue had the strongest association with better cognitive performance. Interventions targeting cancer-related fatigue may help buffer the neurotoxic effects of brain RT.

Limited-Stage Small Cell Lung Cancer: Is Prophylactic Cranial Irradiation Necessary?

PURPOSE: Prophylactic cranial irradiation (PCI) reduces the incidence of brain metastases in patients with limited stage small cell lung cancer (LS-SCLC). However, PCI is associated with neurotoxicity. Previous studies have not consistently used pretreatment magnetic resonance imaging. Modern imaging improvements continue to enhance early metastasis detection, potentially decreasing the utility of PCI. We sought to determine whether PCI was associated with improved outcomes in LS-SCLC patients with modern imaging. METHODS AND MATERIALS: We identified LS-SCLC patients with no intracranial disease who were treated between 2007 and 2018. Kaplan-Meier estimates of overall survival (OS) and progression-free survival (PFS) were calculated and multivariate Cox proportional hazards models were generated. The cumulative incidence of brain metastases was estimated using competing risks methodology. RESULTS: Ninety-two patients were identified without intracranial disease at initial staging, 39 of whom received PCI. Median follow-up was 56.7 months. The median OS for the cohort was 35.5 months (95% CI, 25.8-49.3), and median PFS was 19.1 months (95% CI, 12.3-30.5). Median OS with PCI versus observation was 37.9 months (95% CI, 31.8-not reached) versus 30.5 months (95% CI, 14.6-56.1; P = .07), whereas median PFS was 26.3 months (95% CI 19.1-not reached) versus 12.3 months (95% CI, 8.5-30.5; P = .02), respectively. Overall, at 2 years, the cumulative incidence of brain metastases was 10% with PCI and 29% without; this increased to 32% and 29% by 4 years (P = .66). In those patients who had negative magnetic resonance imaging of the brain after completing initial treatment, the 1-year cumulative incidence of brain metastasis was not significantly different at 8% versus 11% (P = .46) respectively. Both PCI and treatment response were independent predictors for PFS on multivariate analysis. Stratified by disease response, patients with a complete response did not benefit from PCI (P = .50), whereas those with partial response or stable disease experienced improved PFS (P = .01). CONCLUSIONS: Overall, PCI was associated with improved PFS and reduced early incidence of brain metastases. Patients achieving a complete response to initial therapy did not experience a PFS benefit with PCI. This may indicate that subsets of LS-SCLC patients can potentially be spared from PCI in the era of modern imaging.