Factors associated with long-term survival in central nervous system metastases

High prognostic nutritional index could be associated with improved survival in patients with brain metastases: a retrospective observational study

BACKGROUND

Prognostic nutritional index (PNI) is an indicator of immunonutritional status. The present study aimed to evaluate the association between PNI and overall survival in patients with brain metastases.

METHODS

A total of 257 patients with histologically confirmed brain metastasis who underwent surgery at our center between April 2011 and April 2021 were investigated retrospectively.Demographic, clinical, and radiologic data of all cases were extracted. Patients were divided into the low PNI group(PNI <45) (malnutrition status) and the high PNI group (PNI ≥45)(normal nutritional status). Survival analyses were performed using the Kaplan-Meier method and compared using the log-rank test. Univariate and multivariate analyses were performed using the Cox proportional hazards method.

RESULTS

From the 257 cases of brain metastases, there were 148 (57.6%) males and 109 (42.4%) females. The mean age was 57.02 ± 8.7. The median overall survival was 13 months. The results of the multivariate Cox regression analyses showed primary cancer site (HR 2.196, 95% CI 1.988-6.52605, P = 0.000), the number of metastases (HR 1.829, 95% CI 1.380-2.872, P = 0.037), extracranial involvement (HR 2.186, 95% CI 1.213-4.171, P = 0.026), adjuvant radiotherapy (HR 2.823, 95% CI 1.187-5.415, P = 0.017) and PNI (HR 1.961, 95% CI 1.168-3.515, P = 0.021) as the independent predictors of overall survival in patients with brain metastases.

CONCLUSION

Our results suggest that PNI could be associated with survival in patients with brain metastases. Patients with a lower PNI had a significantly worse outcome in comparison with those with a higher PNI. Evaluation of PNI may provide additional prognostic information in patients with brain metastases.

Extended Survival in Patients With Non-Small-Cell Lung Cancer-Associated Brain Metastases in the Modern Era

BACKGROUND

Brain metastases (BM) have long been considered a terminal diagnosis with management mainly aimed at palliation and little hope for extended survival. Use of brain stereotactic radiosurgery (SRS) and/or resection, in addition to novel systemic therapies, has enabled improvements in overall and progression-free (PFS) survival.

OBJECTIVE

To explore the possibility of extended survival in patients with non-small-cell lung cancer (NSCLC) BM in the current era.

METHODS

During the years 2008 to 2020, 606 patients with NSCLC underwent their first Gamma Knife SRS for BM at our institution with point-of-care data collection. We reviewed clinical, molecular, imaging, and treatment parameters to explore the relationship of such factors with survival.

RESULTS

The median overall survival was 17 months (95% CI, 13-40). Predictors of increased survival in a multivariable analysis included age <65 years ( P < .001), KPS ≥80 ( P < .001), absence of extracranial metastases ( P < .001), fewer BM at first SRS (≤3, P = .003), and targeted therapy ( P = .005), whereas chemotherapy alone was associated with shorter survival ( P = .04). In a subgroup of patients managed before 2016 (n = 264), 38 (14%) were long-term survivors (≥5 years), of which 16% required no active cancer treatment (systemic or brain) for ≥3 years by the end of their follow-up.

CONCLUSION

Long-term survival in patients with brain metastases from NSCLC is feasible in the current era of SRS when combined with the use of effective targeted therapeutics. Of those living ≥5 years, the chance for living with stable disease without the need for active treatment for ≥3 years was 16%.

Clinical outcome after CyberKnife® radiosurgery re-irradiation for recurrent brain metastases

PURPOSE

The objective of this study was to elucidate the impact on clinical outcomes resulting from re-irradiation for locally recurrent (LR) brain metastases (BM) using CyberKnife® stereotactic radiosurgery (SRS).

MATERIALS AND METHODS

Seventy-seven patients with 254 LR BM lesions treated using SRS re-irradiation between January 2014 and December 2018 were analysed in this retrospective study. The local control (LC), overall survival (OS) rates, and adverse events were assessed. The adverse events were classified according to the Common terminology for adverse event (CTCAE) v5.0.

RESULTS

The median follow-up duration was 8.9 months. The median age of the patients was 55 years (IQR: 47-62). The 3, 6, and 9-month LC and OS rates were 92.2%, 73.4%, and 73.4% and 79.2%, 61.0%, and 48.1%, respectively. On multivariate analysis the gender (male vs. female; HR, 1.79; 95% CI, 1.06-3.01; P=0.028), type of first brain radiation (WBI vs. SRS) followed by re-irradiation using SRS (HR, 9.32; 95% CI, 2.77-15.27; P<0.001) tumour volume (>12cc vs. ≤12cc; HR, 1.84; 95% CI, 1.10-3.11; P=0.02), and recursive partitioning analysis (RPA) (I vs. II & III; HR, 0.38; 95% CI, 0.19-0.70; P=0.001) were independent predictive factor for OS. Radionecrosis was reported in 3 patients.

CONCLUSION

With acceptable toxicity, SRS re-irradiation for LR BM showed a favourable rate for LC and OS and reported better OS for the female gender, a patient undergoing first brain radiation with SRS, tumour volume ≤12cc, and RPA-I. This result needs to be further evaluated in future clinical studies.

Salting the Soil: Targeting the Microenvironment of Brain Metastases

Paget's "seed and soil" hypothesis of metastatic spread has acted as a foundation of the field for over a century, with continued evolution as mechanisms of the process have been elucidated. The central nervous system (CNS) presents a unique soil through this lens, relatively isolated from peripheral circulation and immune surveillance with distinct cellular and structural composition. Research in primary and metastatic brain tumors has demonstrated that this tumor microenvironment (TME) plays an essential role in the growth of CNS tumors. In each case, the cancerous cells develop complex and bidirectional relationships that reorganize the local TME and reprogram the CNS cells, including endothelial cells, pericytes, astrocytes, microglia, infiltrating monocytes, and lymphocytes. These interactions create a structurally and immunologically permissive TME with malignant processes promoting positive feedback loops and systemic consequences. Strategies to interrupt interactions with the native CNS components, on "salting the soil," to create an inhospitable environment are promising in the preclinical setting. This review aims to examine the general and specific pathways thus far investigated in brain metastases and related work in glioma to identify targetable mechanisms that may have general application across the spectrum of intracranial tumors.

Efficacy of salvage stereotactic radiotherapy (SRT) for locally recurrent brain metastases after initial SRT and characteristics of target population

OBJECTIVES

Due to a steadily growing use of stereotactic radiotherapy (SRT) for treatment of brain metastases (BMs), the in-field failure after an initial stereotaxy is an increasingly frequent problem. Repeat stereotactic radiotherapy (re-SRT) shows encouraging results in terms of local control. However, the evidence on prognostic factors limiting the overall survival (OS) of re-treated patients is scarce. Here, we sought to analyze the patients' and treatment characteristics influencing the survival outcomes after re-SRT.

METHODS

Data of all patients with local failure of initial SRT treated from 2012 to 2019 were retrospectively reviewed and cases treated with salvage SRT were analyzed. We analyzed the impact of patients' and treatment characteristics on overall survival after re-SRT by Kaplan-Meier method and Cox regression models. Local and distant brain control, cause of death, and radionecrosis rate were also assessed.

RESULTS

Forty-seven patients with 55 BMs treated with re-SRT were evaluated. Median OS after re-SRT was 9.2 months and the overall local control was 83.6%. Nine BMs (16.4%) presented local relapse (LR), 12 (21.8%) radionecrosis, while 21 patients (44.7%) developed new BMs. Only absence of extracranial metastases at BMs diagnosis (HR 0.42, CI 95%; 0.18-0.97), extracranial disease progression (HR 2.39, CI 95%; 1.06-5.38) and distant brain failure (HR 3.94, CI 95%; 1.68-9.24) after re-SRT were significantly associated with patients' survival. Extracranial progression following re-SRT was an independent prognosticator of worse OS.

CONCLUSION

Re-SRT after LR presented excellent local control with acceptable RN rate and improved patients' survival, limited mainly by extracranial and distant brain progression.

Tumor microenvironment differences between primary tumor and brain metastases

The present review aimed to discuss contemporary scientific literature involving differences between the tumor microenvironment (TME) in melanoma, lung cancer, and breast cancer in their primary site and TME in brain metastases (BM). TME plays a fundamental role in the behavior of cancer. In the process of carcinogenesis, cells such as fibroblasts, macrophages, endothelial cells, natural killer cells, and other cells can perpetuate and progress carcinogenesis via the secretion of molecules. Oxygen concentration, growth factors, and receptors in TME initiate angiogenesis and are examples of the importance of microenvironmental conditions in the performance of neoplastic cells. The most frequent malignant brain tumors are metastatic in origin and primarily originate from lung cancer, breast cancer, and melanoma. Metastatic cancer cells have to adhere to and penetrate the blood-brain barrier (BBB). After traversing BBB, these cells have to survive by producing various cytokines, chemokines, and mediators to modify their new TME. The microenvironment of these metastases is currently being studied owing to the discovery of new therapeutic targets. In these three types of tumors, treatment is more effective in the primary tumor than in BM due to several factors, including BBB. Understanding the differences in the characteristics of the microenvironment surrounding the primary tumor and their respective metastasis might help improve strategies to comprehend cancer.

Second Re-irradiation of Brain Metastases: A Review of Studies Involving Stereotactic Radiosurgery

Due to advances in the systemic and local treatment, e.g., targeted therapy, immune checkpoint inhibitors, and stereotactic radiotherapy, an increasing proportion of patients with brain metastases now survive for several years. However, long-term survival is not synonymous to permanent local control in the brain. Both local and distant brain relapse sometimes necessitate additional radiotherapy to prevent death from neurologic causes. Prescribing more than two courses of radiotherapy to the same target volume or, in this case, brain metastasis, is a controversial approach. The present review summarizes the results of clinical studies, that included patients treated with whole-brain radiotherapy (WBRT) and two courses of stereotactic radiotherapy to the same, locally recurrent metastasis, and with two courses of WBRT and an additional stereotactic radiotherapy.