Multi-observer concordance and accuracy of the British Thoracic Society scale and other visual assessment qualitative criteria for solid pulmonary nodule assessment using FDG PET-CT

AIM

To compare the interobserver reliability and diagnostic accuracy of the British Thoracic Society (BTS) scale and other visual assessment criteria in the context of 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)-computed tomography (CT) evaluation of solid pulmonary nodules (SPNs).

MATERIALS AND METHODS

Fifty patients who underwent FDG PET-CT for assessment of a SPN were identified. Seven reporters with varied experience at four centres graded FDG uptake visually using the British Thoracic Society (BTS) four-point scale. Five reporters also scored SPNs according to three- and five-point visual assessment scales and using semi-quantitative assessment (maximum standardised uptake value [SUV_max]). Interobserver reliability was assessed with the intra-class correlation coefficient (ICC) and weighted Cohen's kappa (κ). Diagnostic performance was evaluated by receiver operator characteristic (ROC) analysis.

RESULTS

Good interobserver reliability was demonstrated with the BTS scale (ICC=0.78, 95% confidence interval [CI]: 0.69-0.85) and five-point scale (ICC=0.78, 95 CI 0.68-0.86), whilst the three-point scale demonstrated moderate reliability (ICC=0.70, 95% CI: 0.59-0.80). Almost perfect agreement was achieved between two consultants (κ=0.85), and substantial agreement between two other consultants (κ=0.78) using the BTS scale. ROC curves for the BTS and five-point scales demonstrated equivalent accuracy (BTS area under the ROC curve [AUC]=0.768; five-point AUC=0.768). SUV_max was no more accurate compared to the BTS scale (SUV_max AUC=0.794; BTS AUC=0.768, p=0.43).

CONCLUSIONS

The BTS scale can be applied reliably by reporters with varied levels of PET-CT reporting experience, across different centres and has a diagnostic performance that is not surpassed by alternative scales.

Social deprivation does not affect lung cancer stage at presentation or disease outcome

INTRODUCTION

Lung cancer mortality rates are higher in more deprived populations. This may simply reflect higher incidence of the disease, or additionally delayed presentation and worse outcomes amongst more deprived patients. Low socio-economic status (SES) has also been linked to cancer fatalism which might account for such differences. We determined the interaction between SES, patient's characteristics at presentation with lung cancer, and disease outcome at a large UK teaching hospital.

METHODS

Stage, PS at presentation, treatment and survival data, index of multiple deprivation score and ACORN group (geo-demographic segmentation tool) were analysed for 1432 patients.

RESULTS

There were no significant differences in stage or PS distribution by IMD quintile or ACORN group. When patients with stage I/II disease were considered, there were no differences in IMD or ACORN group for those undergoing or not undergoing surgical resection. Similarly when the whole cohort was considered, there were no differences in these parameters between those receiving and not receiving any anti-cancer therapy. There was a non-significant trend to lower IMD score (i.e. less deprivation) in the stage IIIb/IV patients receiving palliative chemotherapy compared to those not receiving chemotherapy. There was no significant difference in median survival or one-year survival according to IMD quintile or ACORN group.

CONCLUSION

In our patient cohort, deprivation does not appear to affect stage or performance status at presentation, nor survival from lung cancer. If cancer fatalism is more prevalent in deprived populations, this does not appear to lead to later diagnosis nor worse disease outcome.

KL-6 levels are elevated in plasma from patients with acute respiratory distress syndrome

The acute respiratory distress syndrome (ARDS) is an extreme form of lung injury characterised by disruption to the alveolar epithelium. KL-6 is a mucin-like glycoprotein expressed on type II pneumocytes. Circulating levels of KL-6 have diagnostic and prognostic significance in a number of interstitial lung diseases, and when elevated are thought to indicate disruption of the alveolar epithelial lining. In this study, the authors sought to determine whether plasma KL-6 levels were elevated in patients with ARDS and whether these were associated with aetiology, disease severity, outcome or ventilatory strategy. Plasma samples were collected from 28 patients with ARDS, nine ventilated controls of matched illness severity and 10 healthy individuals. KL-6 concentrations were measured by enzyme-linked immunosorbent assay. Patients with ARDS had higher plasma levels of KL-6 (median 537 U x mL(-1), interquartile range (IQR) 383-1,119), as compared to ventilated controls (median 255 U x mL(-1), IQR 83-338) and normal individuals (median 215 U x mL(-1), IQR 149-307). In patients with ARDS, plasma KL-6 levels were higher in nonsurvivors than survivors, and correlated positively with oxygenation index and negatively with arterial oxygen tension:inspiratory oxygen fraction ratio. There were also significant positive correlations with mean and peak airway pressures. Elevated levels of plasma KL-6 may provide a useful marker for acute respiratory distress syndrome in ventilated patients and have possible prognostic significance. Alveolar epithelial cell damage may be influenced by the nature of mechanical ventilatory support.

Pulmonary tuberculosis among political asylum seekers screened at Heathrow Airport, London, 1995-9

BACKGROUND

Over 50% of cases of tuberculosis (TB) in the UK occur in people born overseas, and new entrants to the country are screened for TB. A study was undertaken to determine the prevalence and disease characteristics of pulmonary TB in new entrants to the UK seeking political asylum.

METHODS

A retrospective analysis of the results of screening 53 911 political asylum seekers arriving at Heathrow Airport between 1995 and 1999 was performed by studying Airport Health Control Unit records and hospital medical records. Outcome measures were chest radiograph abnormalities, sputum smear, culture, and drug resistance data for Mycobacterium tuberculosis.

RESULTS

The overall prevalence of active TB in political asylum seekers was 241 per 100 000. There were large variations in prevalences of TB between asylum seekers from different regions, with low rates from the Middle East and high rates from the Indian subcontinent and sub-Saharan Africa. The frequency of drug resistance was high; 22.6% of culture positive cases were isoniazid resistant, 7.5% were multidrug resistant (resistant to both isoniazid and rifampicin), and 4% of cases diagnosed with active disease had multidrug resistant TB.

CONCLUSIONS

The prevalence rate of TB in political asylum seekers entering the UK through Heathrow Airport is high and more M tuberculosis isolates from asylum seekers are drug resistant than in the UK population. Extrapolating these figures, it is estimated that 101 political asylum seekers with active pulmonary TB enter the UK every year, of whom about 25 would have smear positive disease.