Prevalence and risk factors of brain metastases in patients with newly diagnosed advanced non-small-cell lung cancer

Prevalence of asymptomatic brain metastases in metastatic nonsquamous nonsmall cell lung cancer: Treatment implications for resource-constrained settings

BACKGROUND

Brain metastases (BM) are common in metastatic nonsmall cell lung cancer (NSCLC). However, routine neuroimaging in asymptomatic patients with metastatic NSCLC is controversial as there is no conclusive evidence of benefit from the detection and treatment of asymptomatic BM. Herein, we evaluated the prevalence of asymptomatic BM and its treatment implications in a resource-limited setting.

METHODS

Consecutive patients with newly diagnosed, treatment-naïve, metastatic, nonsquamous NSCLC (NS-NSCLC) were included. Subjects who already had clinical or radiological features suggestive of BM were excluded from the study. All eligible subjects underwent contrast-enhanced magnetic resonance imaging (MRI) of the brain. Management of the detected BM was at the discretion of the treating clinicians.

RESULTS

Among 809 subjects who were screened, 100 (12.4%) were included in the study and underwent MRI. BM was present in 30 (30%) of the subjects and absent in the remaining 70 subjects. A majority of BM were multiple (70%), involved the frontal lobe commonly (73.3%), and had a mean (standard deviation) size of 13.2 (7.3) mm. Detection of BM resulted in a treatment alteration in 17 (17%) of the study subjects (brain irradiation, n = 17, change in targeted therapy, n = 3) with BM. There was no difference in survival of patients who underwent treatment alteration for management of BM compared to those who did not (P = 0.132).

CONCLUSIONS

About one-third of patients with metastatic NS-NSCLC had BM in MRI despite the absence of symptoms. Despite treatment of the majority of the patients with BM with brain irradiation, there was no demonstrable survival benefit. Hence, we conclude that although routine neuroimaging of asymptomatic patients with newly diagnosed metastatic NSCLC may result in treatment alteration (primarily brain irradiation) in a small proportion of patients, it may not influence outcomes in resource-constrained settings.

The effect of smoking on survival in lung carcinoma patients with brain metastasis: a systematic review and meta-analysis

The effects of smoking on survival in BM patients have yet to be reviewed and meta-analysed. However, previous studies have shown that smokers had a greater risk of dying from lung cancer compared to non-smokers. This meta-analysis, therefore, aimed to analyse the effects of cigarette smoking on overall survival (OS) and progression-free survival (PFS) in lung cancer BM patients. PubMed, Embase, Web of Science, Cochrane and Google Scholar were searched for comparative studies regarding the effects of smoking on incidence and survival in brain metastases patients up to December 2020. Three independent reviewers extracted overall survival (OS) and progression-free survival data (PFS). Random-effects models were used to pool multivariate-adjusted hazard ratios (HR). Out of 1890 studies, fifteen studies with a total of 2915 patients met our inclusion criteria. Amongst lung carcinoma BM patients, those who were smokers (ever or yes) had a worse overall survival (HR: 1.34, 95% CI 1.13, 1.60, I2: 72.1%, p-heterogeneity < 0.001) than those who were non-smokers (never or no). A subgroup analysis showed the association to remain significant in the ever/never subgroup (HR: 1.34, 95% CI 1.11, 1.63) but not in the yes/no smoking subgroup (HR: 1.30, 95% CI 0.44, 3.88). This difference between the two subgroups was not statistically significant (p = 0.91). Amongst lung carcinoma BM patients, smoking was associated with a worse OS and PFS. Future studies examining BMs should report survival data stratified by uniform smoking status definitions.

Emerging Gene Fusion Drivers in Primary and Metastatic Central Nervous System Malignancies: A Review of Available Evidence for Systemic Targeted Therapies

Primary and metastatic tumors of the central nervous system present a difficult clinical challenge, and they are a common cause of disease progression and death. For most patients, treatment consists primarily of surgery and/or radiotherapy. In recent years, systemic therapies have become available or are under investigation for patients whose tumors are driven by specific genetic alterations, and some of these targeted treatments have been associated with dramatic improvements in extracranial and intracranial disease control and survival. However, the success of other systemic therapies has been hindered by inadequate penetration of the drug into the brain parenchyma. Advances in molecular characterization of oncogenic drivers have led to the identification of new gene fusions driving oncogenesis in some of the most common sources of intracranial tumors. Systemic therapies targeting many of these alterations have been approved recently or are in clinical development, and the ability to penetrate the blood-brain barrier is now widely recognized as an important property of such drugs. We review this rapidly advancing field with a focus on recently uncovered gene fusions and brain-penetrant systemic therapies targeting them.

IMPLICATIONS FOR PRACTICE

Driver gene fusions involving receptor tyrosine kinases have been identified across a wide range of tumor types, including primary central nervous system (CNS) tumors and extracranial solid tumors that are associated with high rates of metastasis to the CNS (e.g., lung, breast, melanoma). This review discusses the systemic therapies that target emerging gene fusions, with a focus on brain-penetrant agents that will target the intracranial disease and, where present, also extracranial disease.

Inhibition of yes-associated protein suppresses brain metastasis of human lung adenocarcinoma in a murine model

Yes‐associated protein (YAP) is a main mediator of the Hippo pathway and promotes cancer development and progression in human lung cancer. We sought to determine whether inhibition of YAP suppresses metastasis of human lung adenocarcinoma in a murine model. We found that metastatic NSCLC cell lines H2030‐BrM3(K‐ras^G12C mutation) and PC9‐BrM3 (EGFR^Δexon19 mutation) had a significantly decreased p‐YAP(S127)/YAP ratio compared to parental H2030 (K‐ras^G12C mutation) and PC9 (EGFR^Δexon19 mutation) cells (P < .05). H2030‐BrM3 cells had significantly increased YAP mRNA and expression of Hippo downstream genes CTGF and CYR61 compared to parental H2030 cells (P < .05). Inhibition of YAP by short hairpin RNA (shRNA) and small interfering RNA (siRNA) significantly decreased mRNA expression in downstream genes CTGF and CYR61 in H2030‐BrM3 cells (P < .05). In addition, inhibiting YAP by YAP shRNA significantly decreased migration and invasion abilities of H2030‐BrM3 cells (P < .05). We are first to show that mice inoculated with YAP shRNA‐transfected H2030‐BrM3 cells had significantly decreased metastatic tumour burden and survived longer than control mice (P < .05). Collectively, our results suggest that YAP plays an important role in promoting lung adenocarcinoma brain metastasis and that direct inhibition of YAP by shRNA suppresses H2030‐BrM3 cell brain metastasis in a murine model.

Brain metastases in non-small cell lung cancer patients on epidermal growth factor receptor tyrosine kinase inhibitors: symptom and economic burden

OBJECTIVE

This study describes the symptom and economic burden associated with brain metastases (BM) in patients with non-small cell lung cancer (NSCLC) receiving epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs).

METHODS

This retrospective study included adults with ≥2 medical claims, within 90 days, for lung cancer and ≥1 administration of EGFR-TKIs. Based on ICD-9 codes, patients were stratified into cohorts by type of metastases (BM, other metastases [OM], or no metastases [NM]), and by when the metastasis diagnosis occurred (synchronous or asynchronous).

RESULTS

The population (synchronous BM [SBM] = 24, synchronous OM [SOM] = 23, asynchronous BM [ASBM] = 15, asynchronous OM [ASOM] = 49, NM = 85) was mostly female (57%), average age 69 years (SD = 11). SBM patients experienced more fatigue and nausea/vomiting compared with SOM and NM patients and more headaches and loss of appetite than NM patients. ASBM was associated with more fatigue, nausea/vomiting, headaches, pain/numbness, altered mental status, and seizures than NM, and more headaches and pain/numbness than ASOM. SBM patients experienced a greater increase in per-member-per-month all-cause total healthcare costs after diagnosis ($20,301) vs SOM ($9,131, p = .001) and NM ($2,493, p = .001). ASBM's cost increase between baseline and follow-up ($7,867) did not differ from ASOM's ($4,947, p = .195); both were larger than NM ($2,493, p = .001 and p = .009, respectively).

LIMITATIONS

EGFR mutation status was inferred based on EGFR-TKI treatment, not by molecular testing. Patients were from US commercial insurance plans; results may not be generalizable to other populations.

CONCLUSIONS

Among patients with EGFR-TKI-treated NSCLC, patients with BM experienced more symptoms and, when diagnosed synchronously, had significant increases in total medical costs vs patients with OM and NM. Therapeutic options with central nervous system activity may offer advantages in symptomatology and costs in EGFR-mutated patients with BM.