Role of radiotherapy in the management of brain metastases of NSCLC - Decision criteria in clinical routine

BACKGROUND

Whole brain radiotherapy (WBRT) is a common treatment option for brain metastases secondary to non-small cell lung cancer (NSCLC). Data from the QUARTZ trial suggest that WBRT can be omitted in selected patients and treated with optimal supportive care alone. Nevertheless, WBRT is still widely used to treat brain metastases secondary to NSCLC. We analysed decision criteria influencing the selection for WBRT among European radiation oncology experts.

METHODS

Twenty-two European radiation oncology experts in lung cancer as selected by the European Society for Therapeutic Radiation Oncology (ESTRO) for previous projects and by the Advisory Committee on Radiation Oncology Practice (ACROP) for lung cancer were asked to describe their strategies in the management of brain metastases of NSCLC. Treatment strategies were subsequently converted into decision trees and analysed for agreement and discrepancies.

RESULTS

Eight decision criteria (suitability for SRS, performance status, symptoms, eligibility for targeted therapy, extra-cranial tumour control, age, prognostic scores and "Zugzwang" (the compulsion to treat)) were identified. WBRT was recommended by a majority of the European experts for symptomatic patients not suitable for radiosurgery or fractionated stereotactic radiotherapy. There was also a tendency to use WBRT in the ALK/EGFR/ROS1 negative NSCLC setting.

CONCLUSION

Despite the results of the QUARTZ trial WBRT is still widely used among European radiation oncology experts.

Applying the QUARTZ Trial Results in Clinical Practice: Development of a Prognostic Model Predicting Poor Outcomes for Non-small Cell Lung Cancers with Brain Metastases

AIMS

The role of whole brain radiotherapy (WBRT) in patients with brain metastases from non-small cell lung cancers (NSCLC) has been questioned. However, no reliable criteria exist to identify patients who do not benefit from WBRT. The objective of the current study was to develop a prognostic model to identify such patients whose survival matches that of the Quality of Life after Treatment for Brain Metastases (QUARTZ) study.

MATERIALS AND METHODS

Outcome data of patients with NSCLC with brain metastases undergoing WBRT enrolled in a prospective observational study in a tertiary cancer centre were used to develop a prognostic model. Baseline clinico-radiological factors were used for development of the model. The model was internally validated and calibration accuracy was checked for prediction of 70 day mortality. The generated prognostic model was presented as a nomogram.

RESULTS

The median overall survival of 140 patients enrolled in the study was 166 days (95% confidence interval 108-242 days). The prognostic model identified gender, Karnofsky performance status and epidermal growth factor receptor activating mutation status as significant factors influencing overall survival. The model showed a modest discriminative ability with an optimism-corrected C-index of 0.64. However, model calibration error did reveal a moderate degree of calibration error. The high-risk subgroup identified by the model had a median overall survival of 67 days (95% confidence interval 56-101 days), which was similar to that observed in the QUARTZ trial.

CONCLUSION

This prognostic model derived from traditional clinico-radiological features had a modest ability to identify patients with poor prognosis who may not benefit from WBRT. However, the high-risk subgroup identified using this prognostic model had a survival similar to that observed for patients in the QUARTZ trial.

The fibrogenicity of some respirable dusts measured in mice

A method of bio-assay of the fibrogenicity of respirable dust is described. Quartz, coal, and quartz-coal dust mixtures were administered to mice via the tail vein, and liver collagen was estimated chemically. Groups of mice that had received doses of 10, 15, and 20 mg. of these dusts were killed at intervals of 10, 20, and 30 weeks after injection. There was, in general, a linear relation between liver dust and collagen content, and a higher liver collagen the greater the quartz content of injected dust. At 30 weeks after injection there was good differentiation of the collagen response of liver to dust mixtures of different quartz content. These provide standard curves with which liver collagen response to any unknown dust can be compared. The fibrogenicity of two samples of respirable gold-mine dust was less than would be expected from the quartz content. Dust extracted from a region of massive fibrosis in a coal-miner's lung was more fibrogenic than dust from a lung with simple pneumoconiosis.

The action of variable amounts of quartz on the lungs of rats; the extent of pathological change in relation to the amount injected

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The action of small amounts of quartz and larger amounts of coal and graphite on the lungs of rats

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