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.

Multi-Omics Analysis of Brain Metastasis Outcomes Following Craniotomy.

BACKGROUND: The incidence of brain metastasis continues to increase as therapeutic strategies have improved for a number of solid tumors. The presence of brain metastasis is associated with worse prognosis but it is unclear if distinctive biomarkers can separate patients at risk for CNS related death. METHODS: We executed a single institution retrospective collection of brain metastasis from patients who were diagnosed with lung, breast, and other primary tumors. The brain metastatic samples were sent for RNA sequencing, proteomic and metabolomic analysis of brain metastasis. The primary outcome was distant brain failure after definitive therapies that included craniotomy resection and radiation to surgical bed. Novel prognostic subtypes were discovered using transcriptomic data and sparse non-negative matrix factorization. RESULTS: We discovered two molecular subtypes showing statistically significant differential prognosis irrespective of tumor subtype. The median survival time of the good and the poor prognostic subtypes were 7.89 and 42.27 months, respectively. Further integrated characterization and analysis of these two distinctive prognostic subtypes using transcriptomic, proteomic, and metabolomic molecular profiles of patients identified key pathways and metabolites. The analysis suggested that immune microenvironment landscape as well as proliferation and migration signaling pathways may be responsible to the observed survival difference. CONCLUSION: A multi-omics approach to characterization of brain metastasis provides an opportunity to identify clinically impactful biomarkers and associated prognostic subtypes and generate provocative integrative understanding of disease.

Stereotactic body radiotherapy for an isolated splenic metastasis from ovarian carcinoma.

Splenic metastases from oligometastatic ovarian carcinoma are a rare occurrence. Usual treatment for splenic metastases includes splenectomy, but some patients are either unable or unwilling to undergo surgery. Stereotactic body radiotherapy (SBRT) is an effective ablative modality for treating metastatic disease. SBRT to abdominopelvic tumors has been shown to be safe and effective for properly-selected patients and is particularly attractive in the oligometastatic setting as an alternative to radical resection. In this case study, we report a patient with an isolated splenic metastasis from ovarian carcinoma treated with 50 Gy in 10 fractions.

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.

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.

Initial SRS for Patients With 5 to 15 Brain Metastases: Results of a Multi-Institutional Experience.

PURPOSE: Several studies evaluating stereotactic radiosurgery (SRS) for patients with >4 brain metastases (BM) demonstrated similar outcomes after treatment of 1, 2 to 4, and 5 to 15 BM; others found clinically significant survival decrements in the latter group. In this review of 8 academic centers, we compared outcomes of patients undergoing initial SRS for 1, 2 to 4, and 5 to 15 BM. METHODS AND MATERIALS: A total of 2089 patients treated with initial SRS for BM were included. Overall survival (OS) was estimated using the Kaplan-Meier method and compared using the log-rank test. Patient and disease characteristics were evaluated for association with OS and cumulative incidence of distant brain failure (DBF) using stepwise multivariable Cox proportional hazards and competing risk regression modeling. RESULTS: In this series, 989 (47%) patients had 1 metastasis, 882 (42%) had 2 to 4 metastases, and 212 (10%) had 5 to 15 metastases treated. Median OS for the 1, 2 to 4, and 5 to 15 BM groups was 14.6, 9.5, and 7.5 months, respectively (log-rank P < .01). Univariate and multivariable analyses revealed no difference in survival between 2 to 4 and 5 to 15 BM. DBF at 1 year was 30%, 41%, and 50%, respectively (Gray's P < .01). Two-year cumulative incidence of salvage SRS decreased with increasing number of BM (1: 21% vs 2-4: 19% vs 5-15: 13%; P < .01), but no difference in salvage whole brain radiation therapy was observed (1: 12% vs 2-4: 15% vs 5-15: 16%, P = .10). At the time of DBF, median brain metastasis velocity was 3.9, 6.1, and 11.7 new metastases per year in the 1, 2 to 4, and 5 to 15 BM groups, respectively (P < .01). CONCLUSIONS: Patients treated with initial SRS for 5 to 15 BM experienced survival similar to that in patients with 2 to 4 BM. Lower rates of salvage SRS were observed in the 5 to 15 BM group, with no difference in rates of salvage whole brain radiation therapy.

Impact of diabetes mellitus on outcomes in patients with brain metastasis treated with stereotactic radiosurgery.

PURPOSE: To determine the influence of diabetes mellitus (DM) on outcomes in patients with brain metastasis treated with stereotactic radiosurgery (SRS). METHODS: We retrospectively reviewed 498 patients with brain metastasis treated at our institution with SRS between January 2012 and March 2017. RESULTS: Eight-four patients (16.9%) held a diagnosis of DM prior to SRS treatment. Diabetics compared to nondiabetics had worse overall survival (OS). DM was found to be a significant predictor of OS on multivariate analysis (HR: 1.41, CI: 1.03-1.92, p = 0.03). When stratified by DM diagnosis, there were no significant differences in incidence of radiation necrosis (p = 0.82), radiation-induced edema (p = 0.88), cerebrospinal fluid leak (p = 0.49), or postoperative infection (p = 0.68). CONCLUSIONS: DM diagnosis was a significant predictor of poorer OS in patients treated for brain metastasis with SRS. Diabetics and nondiabetics experienced similar rates of radiation-associated brain toxicities.