Dynamics of eligibility criteria for central nervous system metastases in non-small cell lung cancer randomized clinical trials over time: A systematic review

Central nervous system metastases in advanced non-small cell lung cancer: A review of the therapeutic landscape

Up to 40% of patients with non-small cell lung cancer (NSCLC) develop central nervous system (CNS) metastases. Current treatments for this subgroup of patients with advanced NSCLC include local therapies (surgery, stereotactic radiosurgery, and, less frequently, whole-brain radiotherapy), targeted therapies for oncogene-addicted NSCLC (small molecules, such as tyrosine kinase inhibitors, and antibody-drug conjugates), and immune checkpoint inhibitors (as monotherapy or combination therapy), with multiple new drugs in development. However, confirming the intracranial activity of these treatments has proven to be challenging, given that most lung cancer clinical trials exclude patients with untreated and/or progressing CNS metastases, or do not include prespecified CNS-related endpoints. Here we review progress in the treatment of patients with CNS metastases originating from NSCLC, examining local treatment options, systemic therapies, and multimodal therapeutic strategies. We also consider challenges regarding assessment of treatment response and provide thoughts around future directions for managing CNS disease in patients with advanced NSCLC.

Resection of the Primary Tumor and Survival in Patients with Single-Site Synchronous Oligometastatic Non-Small Cell Lung Cancer: Propensity-Matched Analysis of the National Cancer Database

BACKGROUND

Local therapy for the primary tumor is postulated to remove resistant cancer cells as well as immunosuppressive cells from the tumor microenvironment, potentially improving response to systemic therapy (ST). We sought to determine whether resection of the primary tumor was associated with overall survival (OS) in a multicentric cohort of patients with single-site synchronous oligometastatic non-small cell lung cancer.

STUDY DESIGN

Using the National Cancer Database (2018 to 2020), we evaluated patients with clinical stage IVA disease who received ST and stratified the cohort based on receipt of surgery for the primary tumor (S). We used multivariable and propensity score-matched analysis to study factors associated with S (logistic regression) and OS (Cox regression and Kaplan-Meier), respectively.

RESULTS

Among 12,215 patients identified, 2.9% (N = 349) underwent S and 97.1% (N = 11,886) ST (chemotherapy or immunotherapy) without surgery. Patients who underwent S were younger, more often White, had higher income levels, were more likely to have private insurance, and were more often treated at an academic facility. Among those who received S, 22.9% (N = 80) also underwent resection of the distant metastatic site. On multivariable analysis, metastasis to bone, N+ disease, and higher T-stages were independently associated with less S. On Cox regression, S and resection of the metastatic site were associated with improved survival (hazard ratio 0.67, 95% CI 0.56 to 0.80 and hazard ratio 0.80, 95% CI 0.72 to 0.88, respectively). After propensity matching, OS was improved in patients undergoing S (median 36.8 vs 20.8 months, log-rank p < 0.001).

CONCLUSIONS

Advances in ST for non-small cell lung cancer may change the paradigm of eligibility for surgery. This study demonstrates that surgical resection of the primary tumor is associated with improved OS in selected patients with single-site oligometastatic disease.

Impact of first-line immunotherapy on survival and intracranial outcomes in a cohort of non-small cell lung cancer patients with brain metastases at diagnosis

BACKGROUND

Although brain metastases (BM) at diagnosis are common in non-squamous NSCLC patients (ns-NSCLC), they have been mostly excluded from randomized trials. The aim of this retrospective study was to evaluate real-word outcomes of frontline immune checkpoint inhibitor (ICI) in these patients.

METHODS

Our study assess the intracranial and overall efficacy of first-line ICI-based therapy compared to chemotherapy (CT) in ns-NSCLC patients diagnosed with BM, showing no targetable alterations. Patients were divided according to systemic therapy: CT, ICI, or CT-ICI. Primary endpoint was overall survival (OS), compared using Kaplan-Meier and Cox methodology. Secondary endpoint was intracranial progression free survival (icPFS).

RESULTS

Between 01 and 2018 and 05-2021, 118 patients were included (52 CT, 38 ICI and 28 CT-ICI). Median follow-up was 30.0 months. Intracranial radiotherapy was delivered for 75.0%, 68.4% and 67.9% of patients for CT, ICI and CT-ICI groups (p = 0.805). After adjustment, ICI and CT-ICI were associated with a better OS compared to CT (HR = 0.46, 95 %CI: 0.23-0.89, and HR = 0.52, 95 %CI: 0.27-1.01, respectively). ICI and CT-ICI were associated with a significant reduction in the risk of intracranial progression by 54% (HR = 0.46, 95 %CI: 0.25-0.84) and 59% (HR = 0.41, 95 %CI: 0.23-0.77) compared to CT. Stereotactic radiosurgery was associated with an increased icPFS compared to systemic therapy alone (HR = 0.51, 95% CI: 0.29 - 0.92), whereas whole-brain was not.

CONCLUSIONS

Real-life ns-NSCLC patients with BM at diagnosis treated frontline with ICI presented OS and icPFS benefit compared to CT alone. A prospective assessment of the ideal type and sequence of systemic and local therapy should be conducted.

The Current Landscape of Immune Checkpoint Inhibitor Immunotherapy for Primary and Metastatic Brain Tumors

Antibodies against immune checkpoint inhibitors (ICIs) have revolutionized the treatment of multiple aggressive malignancies, including melanoma and non-small cell lung cancer. ICIs for the treatment of primary and metastatic brain tumors have been used with varying degrees of success. Here, we discuss the available evidence for the use of ICIs in the treatment of primary and metastatic brain tumors, highlighting challenges and opportunities for furthering this type of cancer immunotherapy in neuro-oncology.

Emerging Systemic Treatment Perspectives on Brain Metastases: Moving Toward a Better Outlook for Patients

The diagnosis of brain metastases has historically been a dreaded, end-stage complication of systemic disease. Additionally, with the increasing effectiveness of systemic therapies that prolong life expectancy and improved imaging tools, the incidence of intracranial progression is becoming more common. Within this context, there has been increasing attention directed at understanding the molecular underpinnings of intracranial progression. Exploring the unique features of brain metastases compared with their extracranial counterparts to identify aberrant signaling pathways, which can be targeted pharmacologically, may help lead to new treatments for this patient population. Additionally, critical discoveries outside the sphere of the central nervous system are increasingly being applied to brain metastases with the emergence of immune checkpoint inhibition, becoming a prevalent treatment option for patients with brain metastases across multiple histologies. As novel treatment strategies are considered, they require thoughtful incorporation of agents that can cross the blood-brain barrier and can synergize with pre-existing agents through rational combinations. Lastly, as clinicians and scientists continue to understand key molecular features of these tumors, they will continue to influence the treatment algorithms that are developing for the management of these patients. Due to the complexity of treatment decisions for patients with brain metastases, an emerging tool is the utilization of multidisciplinary brain metastasis tumor boards to ensure optimal treatment decisions are made and that patients are provided access to applicable clinical trials. Looking to the future, the collective effort to understand the various tumor-intrinsic and tumor-extrinsic factors that promote central nervous system seeding and propagation will have the potential to change the clinical trajectory for these patients.