Multimodality treatment of brain metastases from renal cell carcinoma in the era of targeted therapy

Improving Brain Metastases Outcomes Through Therapeutic Synergy Between Stereotactic Radiosurgery and Targeted Cancer Therapies

Brain metastases are the most common form of brain cancer. Increasing knowledge of primary tumor biology, actionable molecular targets and continued improvements in systemic and radiotherapy regimens have helped improve survival but necessitate multidisciplinary collaboration between neurosurgical, medical and radiation oncologists. In this review, we will discuss the advances of targeted therapies to date and discuss findings of studies investigating the synergy between these therapies and stereotactic radiosurgery for non-small cell lung cancer, breast cancer, melanoma, and renal cell carcinoma brain metastases.

Survival benefit with resection of brain metastases from renal cell carcinoma in the setting of molecular targeted therapy and/or immune therapy

Patient survival with renal cell carcinoma (RCC) has improved with the use of molecular targeted agents and immunotherapy. Given the potential activity of these agents in treating brain metastases, the role of aggressive local management with surgery and/or radiation may diminish. The aim of this study was to evaluate the role of aggressive local therapy for RCC brain metastasis in the setting of molecular targeted agents and/or checkpoint inhibitor therapy. A retrospective single-center review between 2011-2018 identified patients that developed brain metastasis from RCC. Data analyzed included demographic information, systemic treatments, intracranial interventions, progression free survival and overall survival (OS). Of 1194 patients, 108(9.0%) were diagnosed with brain metastasis from RCC. OS from diagnosis of brain metastasis (OS_BM) was 12.3 months. OS_BM was analyzed based on three treatment groups: systemic therapy (ST) only (2.0 months, n = 23), systemic and radiotherapy (RT + ST) (12.3 months, n = 52), and systemic and radiotherapy plus resection (Surg + RT + ST) (21.7 months, n = 33). Survival benefit was seen with Surg + RT + ST compared to ST (P = 0.001), but not RT + ST (P = 0.081). Progression free survival was significantly prolonged with Surg + RT + ST compared to RT + ST (10.9 vs 5.9 months, respectively, P = 0.04). Variables such as performance status and number of brain metastases at the time of brain metastasis diagnosis did not differ significantly. In the setting of molecular targeted agents and immunotherapy, resection may benefit the appropriate surgical candidate. Prospective clinical trials are necessary to better understand the role of aggressive RCC brain metastasis treatment. Micro Abstract • Renal cell brain metastasis is often excluded from studies and brain metastases effect a large portion of RCC patients. • Retrospective study of 1194 RCC patients, 108 patients had brain metastasis, determination of the role of surgical resection in the setting of recent advances in checkpoint inhibitors. • A benefit was seen in overall survival in patients that had surgical while undergoing radiation therapy and systemic therapies. • In the setting of molecular targeted agents and immunotherapy, resection may benefit the appropriate surgical candidate(s).

Eligibility Criteria and Endpoints in Metastatic Renal Cell Carcinoma Trials

OBJECTIVES

Treatments for metastatic renal cell carcinoma (mRCC) are often compared across trials, but trial eligibility criteria and endpoints differ. In an effort to better align trials, the Definition for the Assessment of Time to event Endpoints in CANcer trials (DATECAN) project published recommendations in 2015 to be used in mRCC clinical trial design. We analyzed mRCC trial criteria to determine if DATECAN's recommendations were followed.

MATERIALS AND METHODS

We compared eligibility criteria across 29 phase 3 mRCC trials conducted between 2003 and 2019. We then evaluated endpoints used in 10 phase 3 trials activated between 2015 and 2019 to determine their compliance with DATECAN's recommendations.

RESULTS

Among the 29 trials, performance status, renal function, and disease characteristics differed in terms of requirements and measures used. In terms of endpoints, the 10 trials did not entirely follow DATECAN's recommendations. In total, 7/10 trials' primary endpoint was progression-free survival (PFS) as recommended; 4/9 trials used PFS as an endpoint but did not publish their definition of PFS, and the 5 that did, included "death from any cause" instead of DATECAN's recommendation of "death from kidney cancer."

CONCLUSIONS

Key eligibility criteria were somewhat inconsistent across the phase 3 mRCC trials studied. Endpoints in the newer trials did not align with DATECAN's recommendations. Not only is greater standardization needed to facilitate meta-analyses and cross-trial comparisons, but as evident from lack of adherence to DATECAN's recommendations, greater promotion and adoption of recommendations are needed to better harmonize trial design.

Impact of Tyrosine Kinase Inhibitors (TKIs) Combined With Radiation Therapy for the Management of Brain Metastases From Renal Cell Carcinoma

Background: Targeted therapy has transformed the outcome for patients with metastatic renal cell carcinoma. Their efficacy and safety have also been demonstrated in brain metastatic RCC. Preclinical evidence suggests synergism of radiation and tyrosine kinase inhibitors. Consequently, several studies have compared their efficacy in the treatment of RCC brain metastases to the era of brain management with surgery/radiation only.

Objectives: We seek to systematically review and meta-analyze the results of those studies that involved comparative intervention groups of brain management; TKIs, and never used TKIs.

Methods and Materials: Online databases (PubMed, EMBASE, Cochrane library, and ClinicalTrials.gov) were searched for comparative studies. Overall survival as the primary outcome of interest, and local brain control, distant control, and adverse events as secondary outcomes of interest were recorded for meta-analysis. Hazard ratios were pooled together using Review Manager 5.3. Fixed effects or random effects model were adopted according to the level of heterogeneity. Subgroup analysis included studies that involved SRS as the local treatment of management.

Results: Overall 7 studies (n = 897) were included for meta-analysis. TKI use was associated with better survival (HR 0.60 [0.52, 0.69], p < 0.00001) and local brain control (HR 0.34 [0.11, 0.98], p = 0.05). SRS subgroup also revealed significantly better survival (HR 0.61 [0.44, 0.83], p = 0.002) and local brain control (HR 0.19 [0.08, 0.45], p = 0.0002). Distant brain control (HR 0.95 [0.67, 1.35], p = 0.79) and brain progression free survival were unaffected (HR 0.94 [0.56, 1.56], p = 0.80). Only one study (n = 376) reported significantly greater 12-months cumulative incidence of radiation necrosis with TKI use within 30 days of SRS (10.9 vs. 6.4%, p = 0.04).

Conclusions: TKIs use in combination with SRS is safe and effective for treating RCC brain metastases. Larger randomized controlled trials are warranted to validate the results.

Adaptive radiosurgery based on two simultaneous dose prescriptions in the management of large renal cell carcinoma brain metastases in critical areas: Towards customization

Background:

The long-term benefits of local therapy in metastatic renal cell carcinoma (mRCC) have been widely documented. In this context, single fraction gamma knife radiosurgery (SF-GKRS) is routinely used in the management of brain metastases. However, SF-GKRS is not always feasible due to volumetric and regional constraints. We intend to illustrate how a dose-volume adaptive hypofractionated GKRS technique based on two concurrent dose prescriptions termed rapid rescue radiosurgery (RRR) can be utilized in this particular scenario.

Case Description:

A 56-year-old man presented with left-sided hemiparesis; the imaging showed a 13.1 cc brain metastasis in the right central sulcus (Met 1). Further investigation confirmed the histology to be a metastatic clear cell RCC. Met 1 was treated with upfront RRR. Follow-up magnetic resonance imaging (MRI) at 10 months showed further volume regression of Met 1; however, concurrently, a new 17.3 cc lesion was reported in the boundaries of the left frontotemporal region (Met 2) as well as a small metastasis (<1 cc) in the left temporal lobe (Met 3). Met 2 and Met 3 underwent RRR and SF-GKRS, respectively.

Results:

Gradual and sustained tumor ablation of Met 1 and Met 2 was demonstrated on a 20 months long follow- up. The patient succumbed to extracranial disease 21 months after the treatment of Met 1 without evidence of neurological impairment post-RRR.

Conclusion:

Despite poor prognosis and precluding clinical factors (failing systemic treatment, eloquent location, and radioresistant histology), RRR provided optimal tumor ablation and salvage of neurofunction with limited toxicity throughout follow-up.

Supportive roles of brain macrophages in CNS metastases and assessment of new approaches targeting their functions

Metastases to the central nervous system (CNS) occur frequently in adults and their frequency increases with the prolonged survival of cancer patients. Patients with CNS metastases have short survival, and modern therapeutics, while effective for extra-cranial cancers, do not reduce metastatic burden. Tumor cells attract and reprogram stromal cells, including tumor-associated macrophages that support cancer growth by promoting tissue remodeling, invasion, immunosuppression and metastasis. Specific roles of brain resident and infiltrating macrophages in creating a pre-metastatic niche for CNS invading cancer cells are less known. There are populations of CNS resident innate immune cells such as: parenchymal microglia and non-parenchymal, CNS border-associated macrophages that colonize CNS in early development and sustain its homeostasis. In this study we summarize available data on potential roles of different brain macrophages in most common brain metastases. We hypothesize that metastatic cancer cells exploit CNS macrophages and their cytoprotective mechanisms to create a pre-metastatic niche and facilitate metastatic growth. We assess current pharmacological strategies to manipulate functions of brain macrophages and hypothesize on their potential use in a therapy of CNS metastases. We conclude that the current data strongly support a notion that microglia, as well as non-parenchymal macrophages and peripheral infiltrating macrophages, are involved in multiple stages of CNS metastases. Understanding their contribution will lead to development of new therapeutic strategies.

Long-term Survival in a Case of Renal Cell Carcinoma With Brain Metastases: A Case Report

Renal cell carcinoma with brain metastases is considered to have a poor prognosis. We are reporting a case of a 63-year-old male who showed excellent long term remission with a combination treatment of radiation and tyrosine kinase inhibitor for a solitary lesion in the brain, secondary to the renal tumor.

Angiosarcoma-related cerebral metastases: a systematic review of the literature

Angiosarcoma-related cerebral metastases have only been recorded in a few case reports and case series and have not been systematically reviewed to date. Our objective was therefore to perform a systematic literature review on cases of angiosarcomas metastasizing to the brain to inform current practice. All three major libraries-PubMed/MEDLINE, Embase, and Cochrane-were systematically searched, until January 2019. Articles in English reporting angiosarcoma-related cerebral metastases via hematogenous route were included. Our search yielded 45 articles (38 case reports, 5 retrospective studies, 1 case series and 1 letter to the editor), totaling 48 patients (mean age 47.9 years). The main primary site was the heart. The mean time of diagnosis of cerebral metastases following primary tumor identification was 4.9 months. In 15 cases, the brain was the only metastatic site. In cases of multiple extracerebral metastases, the most common sites were the lung and bone. Acute intracerebral supratentorial hemorrhage was the most common presenting radiological feature. Treatment strategies were almost equally divided between the surgical (with or without adjuvant treatment) and the medical arm. Mean overall survival was 7.2 months while progression-free survival was 1.5 months. To our knowledge, this is the first systematic literature review on angiosarcoma-related cerebral metastases. This pathology proves to be an extremely rare clinical entity and carries a poor prognosis, and no consensus has been reached regarding treatment.

Prognostic factors and survival in Japanese patients with brain metastasis from renal cell cancer

BACKGROUND

Patients with brain metastasis from renal cell carcinoma have poor outcomes despite recent advances in diagnosis and treatment. Moreover, factors affecting such poor outcomes are unclear. This study aimed to evaluate the prognostic factors associated with overall survival in renal cell carcinoma patients with brain metastasis.

METHODS

We retrospectively reviewed the data of 50 consecutive patients with brain metastasis from renal cell carcinoma at our institution between 1988 and 2017. The evaluated prognostic factors for overall survival included clinicopathological factors at diagnosis, treatment for brain metastasis, and the Graded Prognostic Assessment score of renal cell carcinoma. The associations between preoperative clinicopathological factors and overall survival were assessed using the log-rank test and Cox proportional hazards models for univariate and multivariate analyses, respectively.

RESULTS

Forty-five patients were included, among whom 39 died during follow-up. The median follow-up was 8.2 months. The median survival time was 8.2 months (95% confidence interval 5.5-13.7). A Graded Prognostic Assessment score ≤ 2 (hazard ratio 1.967; 95% confidence interval 1.024-3.892; P = 0.042), the presence of sarcomatoid components (hazard ratio 3.299; 95% confidence interval 1.424-7.193; P = 0.007), and no treatment for brain metastasis (hazard ratio 2.594; 95% confidence interval 1.033-5.858; P = 0.043) were independently associated with poor prognosis in the multivariate analysis.

CONCLUSIONS

Patients with renal cell carcinoma who develop brain metastasis have poor overall survival. The Graded Prognostic Assessment score, sarcomatoid components, and treatment for brain metastasis from renal cell carcinoma were independent factors associated with prognosis.

Improved Survival Outcomes for Kidney Cancer Patients With Brain Metastases

BACKGROUND

Brain metastases (BM) occur frequently in patients with metastatic kidney cancer and are a significant source of morbidity and mortality. Although historically associated with a poor prognosis, survival outcomes for patients in the modern era are incompletely characterized. In particular, outcomes after adjusting for systemic therapy administration and International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk factors are not well-known.

PATIENTS AND METHODS

A retrospective database of patients with metastatic renal cell carcinoma (RCC) treated at University of Texas Southwestern Medical Center between 2006 and 2015 was created. Data relevant to their diagnosis, treatment course, and outcomes were systematically collected. Survival was analyzed by the Kaplan-Meier method. Patients with BM were compared with patients without BM after adjusting for the timing of BM diagnosis, either prior to or during first-line systemic therapy. The impact of stratification according to IMDC risk group was assessed.

RESULTS

A total of 56 (28.4%) of 268 patients with metastatic RCC were diagnosed with BM prior to or during first-line systemic therapy. Median overall survival (OS) for systemic therapy-naive patients with BM compared with matched patients without BM was 19.5 versus 28.7 months (P = .0117). When analyzed according to IMDC risk group, the median OS for patients with BM was similar for favorable- and intermediate-risk patients (not reached vs. not reached; and 29.0 vs. 36.7 months; P = .5254), and inferior for poor-risk patients (3.5 vs. 9.4 months; P = .0462). For patients developing BM while on first-line systemic therapy, survival from the time of progression did not significantly differ by presence or absence of BM (11.8 vs. 17.8 months; P = .6658).

CONCLUSIONS

Survival rates for patients with BM are significantly better than historical reports. After adjusting for systemic therapy, the survival rates of patients with BM in favorable- and intermediate-risk groups were remarkably better than expected and not statistically different from patients without BM, though this represents a single institution experience, and numbers are modest.

Stereotactic Radiosurgery for Multiple Brain Metastases From Renal-Cell Carcinoma

BACKGROUND

Brain metastases (BM) pose a significant problem in patients with metastatic renal-cell carcinoma (mRCC). Local and systemic therapies including stereotactic radiosurgery (SRS) are rapidly evolving, necessitating reassessments of outcomes for modern patient management.

PATIENTS AND METHODS

The mRCC patients with BM treated with SRS were reviewed. Patient demographics, clinical history, and SRS treatment parameters were identified.

RESULTS

Among 268 patients with mRCC treated between 2006 and 2015, 38 patients were identified with BM. A total of 243 BM were treated with SRS with 1 to 26 BMs treated per SRS session (median, 2 BMs). The median (range) BM size was 0.6 (0.2-3.1) cm and median (range) SRS treatment dose was 18 (12-24) Gy. Treated BM local control rates at 1 and 2 years were 91.8% (95% confidence interval, 85.7-95.4) and 86.1% (95% confidence interval, 77.1-91.7), respectively. BM control declined for larger tumors. Survival after 1-year was 57.5% (95% CI 40.2-71.4) for all patients. Survival was not statistically different between patients with < 5 BM versus ≥ 5 BM. Survival was prognostic based on International Metastatic Renal Cell Carcinoma Database (IMDC) risk groups in patients with < 5 BM. Two patients experienced grade 3 radiation necrosis requiring surgical intervention.

CONCLUSION

SRS is effective in controlling BM in patients with mRCC. Over half of treated patients survive past a year, and no differences in survival were noted in patients with > 5 metastases. Prognostic risk categories based on systemic disease (IMDC) are predictive of survival in this BM population, with limited rates of symptomatic radiation necrosis.

Update on the biology and management of renal cell carcinoma

Renal cell cancer (RCC) (epithelial carcinoma of the kidney) represents 2%-4% of newly diagnosed adult tumors. Over the past 2 decades, RCC has been better characterized clinically and molecularly. It is a heterogeneous disease, with multiple subtypes, each with characteristic histology, genetics, molecular profiles, and biologic behavior. Tremendous heterogeneity has been identified with many distinct subtypes characterized. There are clinical questions to be addressed at every stage of this disease, and new targets being identified for therapeutic development. The unique characteristics of the clinical presentations of RCC have led to both questions and opportunities for improvement in management. Advances in targeted drug development and understanding of immunologic control of RCC are leading to a number of new clinical trials and regimens for advanced disease, with the goal of achieving long-term disease-free survival, as has been achieved in a proportion of such patients historically. RCC management is a promising area of ongoing clinical investigation.

Effect of Targeted Therapies on Prognostic Factors, Patterns of Care, and Survival in Patients With Renal Cell Carcinoma and Brain Metastases

PURPOSE

To identify prognostic factors, define evolving patterns of care, and the effect of targeted therapies in a larger contemporary cohort of renal cell carcinoma (RCC) patients with new brain metastases (BM).

METHODS AND MATERIALS

A multi-institutional retrospective institutional review board-approved database of 711 RCC patients with new BM diagnosed from January 1, 2006, to December 31, 2015, was created. Clinical parameters and treatment were correlated with median survival and time from primary diagnosis to BM. Multivariable analyses were performed.

RESULTS

The median survival for the prior/present cohorts was 9.6/12 months, respectively (P < .01). Four prognostic factors (Karnofsky performance status, extracranial metastases, number of BM, and hemoglobin b) were significant for survival after the diagnosis of BM. Of the 6 drug types studied, only cytokine use after BM was associated with improved survival. The use of whole-brain radiation therapy declined from 50% to 22%, and the use of stereotactic radiosurgery alone increased from 46% to 58%. Nonneurologic causes of death were twice as common as neurologic causes.

CONCLUSIONS

Additional prognostic factors refine prognostication in this larger contemporary cohort. Patterns of care have changed, and survival of RCC patients with BM has improved over time. The reasons for this improvement in survival remain unknown but may relate to more aggressive use of local brain metastasis therapy and a wider array of systemic treatment options for those patients with progressive extracranial tumor.