[Brain metastases from breast cancer: prognostic factors and tailored management]

Identification of markers associated with brain metastasis from breast cancer through bioinformatics analysis and verification in clinical samples

Background

Brain metastasis from breast cancer (BC) is an important cause of BC-related death. The present study aimed to identify markers of brain metastasis from BC.

Methods

Datasets were downloaded from the public databases Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). Weighted gene co-expression network analysis (WGCNA) was performed to identify metastasis-associated genes (MAGs). Least absolute shrinkage and selection operator (LASSO) Cox proportional hazards regression models were constructed for screening key MAGs. Survival analysis and receiver operating characteristic (ROC) curves were used for evaluating the prognostic value. The factors associated with tumor metastasis were integrated to create a nomogram of TCGA data using R software. Gene Set Enrichment Analyses (GSEA) was performed for detecting the potential mechanisms of identified MAGs. Immunohistochemistry (IHC) was used to verify the expression of the key genes in clinical samples.

Results

The genes in 2 modules were identified to be significantly associated with metastasis through WGCNA. LASSO Cox proportional hazards regression models were constructed successfully. Subsequently, a clinical prediction model was constructed, and a nomogram was mapped, which had better sensitivity and specificity for BC metastasis. Two key genes, discs large homolog 3 (DLG3) and growth factor independence 1 (GFI1), were highly expressed in clinical samples, and the expression of these 2 genes was associated with patients' survival time.

Conclusions

We successfully constructed a clinical prediction model for brain metastasis from BC, and identified that the expression of DLG3 and GFI1 were strongly associated with brain metastasis from BC.

Methods and results of local treatment of brain metastases in patients with breast cancer

This article presents methods and results of surgical treatment and radiation therapy of brain metastases in breast cancer patients (brain metastases from breast cancer BMF-BC). Based on the literature data, it was shown that patients with single BMF-BC, aged less than 65 years, with Karnofsky score (KPS) of 70 or more and with cured or controlled extracranial disease are the best candidates to surgical treatment. Irrespective of the extracranial disease control status, there are indications for surgery in patients with symptomatic mass effect (tumour diameter larger than 3 cm) and patients with obstructive hydrocephalus from their BMF-BC. Stereotactic radiosurgery (SRS) has some advantages over surgery, with similar effectiveness: it may be used in the treatment of lesions inaccessible to surgery, the number of lesion is not a limiting factor if each lesion is small (< 3) and adequate doses can be delivered, it is not contraindicated in patients with active extracranial disease, it does not interfere with ongoing systemic treatment, and it does not require general anaesthesia or hospitalisation. A disadvantage of SRS, as compared to whole brain radiotherapy (WBRT), in patients with BMF-BC is the possibility of subsequent development of new lesion in the non-irradiated field. Thus the majority of the BMF-BC patients are not good candidates to surgery or SRS; WBRT alone or combined with a systemic treatment still plays a major role in the treatment of these patients.

Interventions for preventing and ameliorating cognitive deficits in adults treated with cranial irradiation

BACKGROUND

Cognitive deficits are common in people who have received cranial irradiation and have a serious impact on daily functioning and quality of life. The benefit of pharmacological and non-pharmacological treatment of cognitive deficits in this population is unclear.

OBJECTIVES

To assess the effectiveness of interventions for preventing or ameliorating cognitive deficits in adult patients treated with cranial irradiation.

SEARCH METHODS

In August 2014. we searched the Cochrane Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and PsycINFO and checked the reference lists of included studies. We also searched for ongoing trials via ClinicalTrials.gov, the Physicians Data Query and the Meta Register of Controlled Trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that evaluated pharmacological or non-pharmacological interventions in cranial irradiated adults, with objective cognitive functioning as a primary or secondary outcome measure.

DATA COLLECTION AND ANALYSIS

Two review authors (JD, KZ) independently extracted data from selected studies and carried out a 'Risk of bias' assessment. Cognitive function, fatigue and mood outcomes were reported. No data were pooled.

MAIN RESULTS

Sixteen studies were identified for possible inclusion in the review, six of which were included. Three studies investigated prevention and three studies investigated amelioration. Due to differences between studies in the interventions being evaluated, a meta-analysis was not possible. Two studies investigated a pharmacological intervention for the prevention of cognitive deficits; memantine compared with placebo, and d-threo-methylphenidate HCL compared with placebo. In the first study the primary cognitive outcome of memory at six months did not reach significance, but there was significant improvement in overall cognitive function compared to placebo, with similar adverse events across groups. The second study found no statistically significant difference between arms, with few adverse events. The third study investigated a rehabilitation program for the prevention of cognitive deficits but did not carry out a statistical comparison of cognitive performance between groups.Three studies investigated the use of a pharmacological intervention for the treatment of cognitive deficits; methylphenidate compared with modafinil, two different doses of modafinil, and donepezil compared with placebo. The first study found improvements in cognitive function in both the methylphenidate and modafinil arms; few adverse events were reported. The second study combined treatment arms and found improvements across all cognitive tests, however, a number of adverse events were reported. Both studies were limited by a small sample size. The third study did not find an improvement in the primary cognitive outcome of overall performance, but did find improvement in an individual test of memory, compared to placebo; adverse events were not reported. No non-pharmacological studies for the amelioration of cognitive deficits were eligible. There were a number of limitations across studies but few without high risks of bias.

AUTHORS' CONCLUSIONS

There is supportive evidence that memantine may help prevent cognitive deficits for adults with brain metastases receiving cranial irradiation. There is supportive evidence that donepezil may have a role in treating cognitive deficits in adults with primary or metastatic brain tumours who have been treated with cranial irradiation. Patient withdrawal affected the statistical power of both studies. Further research that tries to minimise the withdrawal of consent, and subsequently reduce the requirement for imputation procedures, may offer a higher quality of evidence.There is no strong evidence to support any non-pharmacological interventions (medical or cognitive/behavioural) in the prevention or amelioration of cognitive deficits. Non-randomised studies appear promising but are as yet to be conclusive via translation into high quality evidence. Further research is required.