Lung cancer screening - gaining consensus on next steps - proceedings of a closed workshop in the UK

Lung cancer is the most common cause of cancer death in the UK, and survival from the disease is persistently poor. Efforts to improve outcomes for patients have focused on ways of reducing late diagnosis of the disease, and access to optimal treatment. Research on lung cancer screening has so far provided some evidence of an impact on lung cancer mortality, but there is some debate about whether implementation of a national screening programme should await further trial data, principally that from the NELSON trial. The ongoing poor outcomes and the belief amongst some clinicians that there is sufficient evidence has prompted several local projects testing out lung screening in their communities, sometimes referred to as lung health checks or proactive approaches to high-risk individuals. Funding from NHS England has been forthcoming to support this. Acknowledging roll-out of such activities, which effectively constitute local lung screening in the absence of a NSC recommendation, it was timely to bring key national stakeholders together with academic and clinical experts, to agree a way forward. Cancer Research UK therefore convened a closed workshop in March 2018, involving national and international expertise. This paper outlines the proceedings, key discussion points, highlighted research gaps, and areas of consensus and next steps.

Pulmonary nodules and CT screening: the past, present and future

Lung cancer screening has come a long way since the early studies with chest X-ray. Advancing technology and progress in the processing of images have enabled low dose CT to be tried and tested, and evidence suggests its use can result in a significant mortality benefit. There are several issues that need refining in order to successfully implement screening in the UK and elsewhere. Some countries have started patchy implementation of screening and there is increased recognition that the appropriate management of pulmonary nodules is crucial to optimise benefits of early detection, while reducing harm caused by inappropriate medical intervention. This review summarises and differentiates the many recent guidelines on pulmonary nodule management, discusses screening activity in other countries and exposes the present barriers to implementation in the UK.

The SABRTooth feasibility trial protocol: a study to determine the feasibility and acceptability of conducting a phase III randomised controlled trial comparing stereotactic ablative radiotherapy (SABR) with surgery in patients with peripheral stage I non-small cell lung cancer (NSCLC) considered to be at higher risk of complications from surgical resection

Background

Stage I non-small cell lung cancer (NSCLC) is potentially curable, and surgery is considered to be the standard of care for patients with good performance status and minimal co-morbidity. However, a significant proportion of patients with stage I NSCLC have a poorer performance status and significant medical co-morbidity that make them at higher risk of morbidity and mortality from surgery.

Stereotactic ablative radiotherapy (SABR), which uses modern radiotherapeutic techniques to deliver large doses of radiation, has shown superiority over conventional radiotherapy in terms of local control and toxicity and is a standard of care for patients with stage I NSCLC who are at too high risk for surgery. However, it is not known whether surgery or SABR is the most effective in patients with stage I NSCLC who are suitable for surgery but are less fit and at higher risk surgical complications. Previous randomised studies have failed to recruit in this setting, and therefore, a feasibility study is required to see whether a full randomised control trial would be possible.

Methods/design

SABRTooth is a UK-based, multi-centre, open-label, two-group individually (1:1) randomised controlled feasibility study in patients with peripheral stage I NSCLC considered to be at higher risk from surgical resection. The study will assess the feasibility of conducting a definitive large-scale phase III trial. The primary objective is to assess recruitment rates to provide evidence that, when scaled up, recruitment to a large phase III trial would be possible; the target recruitment being 54 patients in total, over a 21-month period. There are multiple secondary and exploratory objectives designed to explore the optimum recruitment and data collection strategies to help optimise the design of a future phase III trial.

Discussion

To know whether SABR is a better, equivalent or inferior alternative to surgery for higher risk patients is a key question in lung cancer. Other studies comparing SABR to surgery have closed early due to poor recruitment, and therefore, the SABRTooth feasibility study has been designed around the UK National Health Service (NHS) cancer pathway incorporating many design features in order to maximise recruitment for a future definitive phase III trial.

Trial registration

controlled-trials.com ISRCTN13029788

Protocol for PIT: a phase III trial of prophylactic irradiation of tracts in patients with malignant pleural mesothelioma following invasive chest wall intervention

INTRODUCTION

Histological diagnosis of malignant mesothelioma requires an invasive procedure such as CT-guided needle biopsy, thoracoscopy, video-assisted thorascopic surgery (VATs) or thoracotomy. These invasive procedures encourage tumour cell seeding at the intervention site and patients can develop tumour nodules within the chest wall. In an effort to prevent nodules developing, it has been widespread practice across Europe to irradiate intervention sites postprocedure--a practice known as prophylactic irradiation of tracts (PIT). To date there has not been a suitably powered randomised trial to determine whether PIT is effective at reducing the risk of chest wall nodule development.

METHODS AND ANALYSIS

In this multicentre phase III randomised controlled superiority trial, 374 patients who can receive radiotherapy within 42 days of a chest wall intervention will be randomised to receive PIT or no PIT. Patients will be randomised on a 1:1 basis. Radiotherapy in the PIT arm will be 21 Gy in three fractions. Subsequent chemotherapy is given at the clinicians' discretion. A reduction in the incidence of chest wall nodules from 15% to 5% in favour of radiotherapy 6 months after randomisation would be clinically significant. All patients will be followed up for up to 2 years with monthly telephone contact and at least four outpatient visits in the first year.

ETHICS AND DISSEMINATION

PIT was approved by NRES Committee North West-Greater Manchester West (REC reference 12/NW/0249) and recruitment is currently on-going, the last patient is expected to be randomised by the end of 2015. The analysis of the primary end point, incidence of chest wall nodules 6 months after randomisation, is expected to be published in 2016 in a peer reviewed journal and results will also be presented at scientific meetings and summary results published online. A follow-up analysis is expected to be published in 2018.

TRIAL REGISTRATION NUMBER

ISRCTN04240319; NCT01604005; Pre-results.

UK Lung Cancer RCT Pilot Screening Trial: baseline findings from the screening arm provide evidence for the potential implementation of lung cancer screening

Background

Lung cancer screening using low-dose CT (LDCT) was shown to reduce lung cancer mortality by 20% in the National Lung Screening Trial.

Methods

The pilot UK Lung Cancer Screening (UKLS) is a randomised controlled trial of LDCT screening for lung cancer versus usual care. A population-based questionnaire was used to identify high-risk individuals. CT screen-detected nodules were managed by a pre-specified protocol. Cost effectiveness was modelled with reference to the National Lung Cancer Screening Trial mortality reduction.

Results

247 354 individuals aged 50–75 years were approached; 30.7% expressed an interest, 8729 (11.5%) were eligible and 4055 were randomised, 2028 into the CT arm (1994 underwent a CT). Forty-two participants (2.1%) had confirmed lung cancer, 34 (1.7%) at baseline and 8 (0.4%) at the 12-month scan. 28/42 (66.7%) had stage I disease, 36/42 (85.7%) had stage I or II disease. 35/42 (83.3%) had surgical resection. 536 subjects had nodules greater than 50 mm³ or 5 mm diameter and 41/536 were found to have lung cancer. One further cancer was detected by follow-up of nodules between 15 and 50 mm³ at 12 months. The baseline estimate for the incremental cost-effectiveness ratio of once-only CT screening, under the UKLS protocol, was £8466 per quality adjusted life year gained (CI £5542 to £12 569).

Conclusions

The UKLS pilot trial demonstrated that it is possible to detect lung cancer at an early stage and deliver potentially curative treatment in over 80% of cases. Health economic analysis suggests that the intervention would be cost effective—this needs to be confirmed using data on observed lung cancer mortality reduction.

Trial registration

ISRCTN 78513845.

Lung cancer screening and management

Deaths from lung cancer are greater than for any other type of malignancy. Many people present with advanced stage cancer at diagnosis and survival is limited. Low radiation dose CT (LDCT) screening appears to offer part of the solution to this. The US National Lung Screening Trial (NLST) showed a 20% reduction in cancer related mortality and a 6.7% reduction in all cause mortality in patients who had LDCT compared to chest X-ray. Lung Cancer screening is now being implemented in the US using the NLST screening criteria but many questions remain about the details of the methodology of screening and its cost effectiveness. Many of these questions are being answered by ongoing European trials that are reporting their findings. In this review we objectively analyse current research evidence and explore the issues that need to be resolved before implementation, including technical considerations, selection criteria and effective nodule management protocols. We discuss the potential barriers that will be faced when beginning a national screening programme and possible solutions to them.

CT screening for lung cancer: Is the evidence strong enough?

The prevailing questions at this time in both the public mind and the clinical establishment is, do we have sufficient evidence to implement lung cancer Computed Tomography (CT) screening in Europe? If not, what is outstanding? This review addresses the twelve major areas, which are critical to any decision to implement CT screening and where we need to assess whether we have sufficient evidence to proceed to a recommendation for implementation in Europe. The readiness level of these twelve categories in 2015 have been with colour coded, where green indicates we have sufficient evidence, amber is borderline evidence and red requires further evidence. Recruitment from the 'Hard to Reach' community still remains at red, while mortality data, cost effectiveness and screening interval are all categorised as amber. The integration of smoking cessation into CT screening programmes is still considered to be category amber. The US Preventive Services Task Force have recommended that CT screening is implemented in the USA utilising the NLST criteria, apart from continuing screening to 80 years of age. The cost effectiveness of the NLST was calculated to be $81,000/QALY, however, its well recognised that the costs of medical care in the USA, is far higher than that of Europe. Medicare have agreed to cover the cost of screening but have stipulated a number of stringent requirements for inclusion. To date we do not have good CT screening mortality data available in Europe and eagerly await the publication of the NELSON trial data in 2016 and then the pooled UKLS and NELSON data thereafter. However in the meantime we should start planning for implementation in Europe, especially in the areas of the radiological service provision and accreditation, as well as identifying novel mechanisms to recruit from the hardest to reach communities.

Non-small cell lung cancer in young adults: presentation and survival in the English National Lung Cancer Audit

BACKGROUND

Non-small cell lung cancer (NSCLC) in young adults is a rare but devastating illness with significant socioeconomic implications, and studies of this patient subgroup are limited.

AIM

This study employed the National Lung Cancer Audit to compare the clinical features and survival of young adults with NSCLC with the older age groups.

DESIGN

A retrospective cohort review using a validated national audit dataset.

METHODS

Data were analysed for the period between 1 January 2004 and 31 December 2011. Young adults were defined as between 18 and 39 years, and all others were divided into decade age groups, up to the 80 years and above group. We performed logistic and Cox regression analyses to assess clinical outcomes.

RESULTS

Of a total of 1 46 422 patients, 651 (0.5%) were young adults, of whom a higher proportion had adenocarcinoma (48%) than in any other age group. Stage distribution of NSCLC was similar across the age groups and 71% of young patients had stage IIIb/IV. Performance status (PS) was 0-1 for 85%. Young adults were more likely to have surgery and chemotherapy compared with the older age groups and had better overall and post-operative survival. The proportion with adenocarcinoma, better PS and that receiving surgery or chemotherapy diminished progressively with advancing decade age groups.

CONCLUSION

In our cohort of young adults with NSCLC, the majority had good PS despite the same late-stage disease as older patients. They were more likely to have treatment and survive longer than older patients.

Lung cancer survival in England: trends in non-small-cell lung cancer survival over the duration of the National Lung Cancer Audit

Background:

In comparison with other European and North American countries, England has poor survival figures for lung cancer. Our aim was to evaluate the changes in survival since the introduction of the National Lung Cancer Audit (NLCA).

Methods:

We used data from the NLCA to identify people with non-small-cell lung cancer (NSCLC) and stratified people according to their performance status (PS) and clinical stage. Using Cox regression, we calculated hazard ratios (HRs) for death according to the year of diagnosis from 2004/2005 to 2010; adjusted for patient features including age, sex and co-morbidity. We also assessed whether any changes in survival were explained by the changes in surgical resection rates or histological subtype.

Results:

In this cohort of 120 745 patients, the overall median survival did not change; but there was a 1% annual improvement in survival over the study period (adjusted HR 0.99, 95% confidence interval (CI) 0.98–0.99). Survival improvement was only seen in patients with good PS and early stage (adjusted HR 0.97, 95% CI 0.95–0.99) and this was partly accounted for by changes in resection rates.

Conclusion:

Survival has only improved for a limited group of people with NSCLC and increasing surgical resection rates appeared to explain some of this improvement.

How do patient and hospital features influence outcomes in small-cell lung cancer in England?

BACKGROUND

Our aim was to systematically determine how features of patients and hospitals influence access to chemotherapy and survival for people with small-cell lung cancer in England.

METHODS

We linked the National Lung Cancer Audit and Hospital Episode Statistics and used multiple logistic and Cox regression analyses to assess the influence of patient and hospital features on small-cell lung cancer outcomes.

RESULTS

There were 7845 patients with histologically proven small-cell lung cancer. Sixty-one percent (4820) of the patients received chemotherapy. Increasing age, worsening performance status, extensive stage and greater comorbidity all reduced the likelihood of receiving chemotherapy. There was wide variation in access to chemotherapy between hospitals in general and patients first seen in centres with a strong interest in clinical trials had a higher odds of receiving chemotherapy (adjusted odds ratio 1.42, 95% confidence interval (CI) 1.06, 1.90). Chemotherapy was associated with a lower mortality rate (adjusted hazard ratio 0.51, 95% CI 0.46, 0.56).

CONCLUSION

Patients first seen at a hospital with a keen interest in clinical trials are more likely to receive chemotherapy, and chemotherapy was associated with improved survival.

UK Lung Screen (UKLS) nodule management protocol: modelling of a single screen randomised controlled trial of low-dose CT screening for lung cancer

The UK Lung Screen (UKLS) is a randomised controlled trial of the use of low-dose multidetector CT for lung cancer screening. It completed the Health Technology Appraisal (HTA)-funded feasibility stage in October 2009 and the pilot UKLS will be initiated in early 2011. The pilot will randomise 4000 subjects to either low-dose CT screening or no screening. The full study, due to start in September 2012, if progression criteria are met, will randomise a further 28 000 subjects from seven centres in the UK. Subjects will be selected if they have sufficient risk of developing lung cancer according to the Liverpool Lung Project risk model. The UKLS employs the ‘Wald Single Screen Design’, which was modelled in the UKLS feasibility study. This paper describes the modelling of nodule management in UKLS by using volumetric analysis with a single initial screen design and follow-up period of 10 years. This modelling has resulted in the development and adoption of the UKLS care pathway, which will be implemented in the planned CT screening trial in the UK.

Concentrations of ceftibuten in plasma and the respiratory tract following a single 400 mg oral dose

Concentrations of ceftibuten in bronchial mucosa, epithelial lining fluid (ELF) and alveolar macrophages were determined from samples taken from 15 subjects at bronchoscopy following a single 400 mg oral dose. Concentrations at all sites were determined using a microbiological assay method which was unaffected by the trans-isomer of ceftibuten. The time from dosage to bronchoscopy ranged from 1.4 to 20.3 h and the subjects were analysed in three groups according to time after dosing. Group A had a mean time since dosing of 1.9 h with mean serum, mucosal and ELF concentrations of 15.2 mg/l, 5.7 mg/kg and 1.6 mg/l. Group B had a mean time of 6.5 h after dosing with mean serum, mucosal and ELF concentration of 14.0 mg/l, 3.2 mg/kg and 1.6 mg/l. Group C had a mean time of 13.3 h with mean serum, mucosal and ELF levels of 4.1 mg/l, 1.8 mg/kg and 1.2 mg/l. Macrophage-related ceftibuten could only be detected in two subjects. These levels are related to the minimum inhibitory concentrations of ceftibuten against common respiratory pathogens with the exception of Strep. pneumoniae.

Lung cancer outcomes at a UK cancer unit between 1998–2001

There are few data published on lung cancer survival in the UK. Survival rates for lung cancer at a UK Hospital between 1998-2001 are described.

METHODS

Analysis of data collected from multidisciplinary team (MDT) meetings, lung cancer registrations and hospital coding.

RESULTS

835 new lung cancers were diagnosed comprising 597 non-small cell lung cancers (NSCLC) (71%), 133 small cell (SCLC) (16%), and 105 clinical diagnoses (13%). Stage at diagnosis; stage I (25%), II (9%), IIIA (8%), IIIB (23%), IV (35%). Surgery was undertaken in 12%, radical radiotherapy (RT) in 4%, palliative RT in 32%, chemotherapy in 8% and best supportive care (BSC) in 36%. The 3-year cumulative survival for NSCLC was: stage I 39%, stage II 30%, stage III 6%, stage IV 0.5%. Only 46% of patients with stage I-IIIA disease received radical treatment. Reasons included poor lung function (32%), unresectable (24%), co-morbidities (17%), performance status (8%), patient choice (8%), unclear (6%), advanced age (5%).

CONCLUSIONS

Survival figures are similar to other UK studies but do not compare favourably with US and European data. This may be because a large proportion of patients with early stage disease receive palliative care only.

Under utilisation of the 2-week wait initiative for lung cancer by primary care and its effect on the urgent referral pathway

The ‘2-week wait’ scheme for referral of patients with cancer to secondary care coincided with the introduction of Department of Health (DoH) Guidelines on referral of patients with suspected lung cancer. The aim of this study was to examine the impact of this process on the urgent referral pathway for lung cancer. Medical records of all patients referred with suspected lung cancer were reviewed for the year prior to introduction of the 2-week wait and DoH guidelines and for the subsequent 24 months. A total of 1044 patients were referred, of which 650 (62%) were found to have malignancy. In the first and second years of the 2-week wait scheme, only 57 and 58% were referred via the scheme. Department of Health guidelines were followed in all but a small number. Median wait time increased from 7 to 9 days. The proportion of all urgent referrals seen within 2 weeks fell from 84 to 71%. The proportion of non-2-week wait urgent referrals being seen within 2 weeks was only 75.5% in the first year of the scheme and fell further to 60.9% in the second year. The absolute number of referrals rose and the proportion having cancer fell from 78% before the scheme to 46% in the second year. During this time, there was no change in stage at presentation. Symptoms were not helpful in discriminating benign from malignant disease and haemoptysis was actually more common in the benign group. However, over 50% of patients in the benign group were appropriate to be seen in secondary care. The 2-week wait scheme has so far failed to reduced waiting times for lung cancer. The findings of this study suggest that this is partly due to continued usage of urgent referral routes outside the 2-week wait scheme and secondly due to a large increase in referrals, probably generated by the introduction of the DoH guidelines. Some adjustment to the guidelines may be appropriate to reflect more emphasis on the early performance of a chest X-ray and the use of direct access to other imaging modalities such as CT. Patients referred outside the 2-week wait are disadvantaged and thus practitioners would be wise to refer all their patients through the 2-week wait system.

Interpretation of occupational peak flow records: level of agreement between expert clinicians and Oasys-2

BACKGROUND

Oasys-2 is a validated diagnostic aid for occupational asthma that interprets peak expiratory flow (PEF) records as well as generating summary plots. The system removes inconsistency in interpretation, which is important if there is limited agreement between experts. A study was undertaken to assess the level of agreement between expert clinicians interpreting serial PEF measurements in relation to work exposure and to compare the responses given by Oasys-2.

METHOD

35 PEF records from workers under investigation for suspected occupational asthma were available for review. Records included details of nature of work, intercurrent illness, drug therapy, predicted PEF, rest periods, and holidays. Simple plots of PEF and the Oasys-2 generated plots were available. Experts were advised that approximately 1 hour was available to review the records. They were asked to score each work-rest-work (WRW) period and each rest-work-rest (RWR) period for evidence of occupational effect. At the end of each record scores of 0-100% were given for evidence of "asthma" and "occupational effect" for the whole record. Kappa values were calculated for each scored period and for the opinions on the whole record. The scores were converted into four groups (0-25%, 26-50%, 51-75%, 76-100%) and two groups (0-50% and 51-100%) for analysis. This is relevant to scores produced by Oasys-2. Agreement between Oasys-2 scores and each expert was calculated.

RESULTS

24 of 35 records were analysed by seven experts in the allotted time. For whole record occupational effect, median kappa values were 0.83 (range 0.56-0.94) for two groups and 0.62 (0.11-0.83) for four groups. For asthma, median kappa values were 0.58 (0-0.67) and 0.42 (0.15-0.70) for two and four groups respectively. For all WRW and RWR periods kappa values were 0.84 (0.42-0.94) and 0.70 (0.46-0.87) respectively. Agreement between Oasys-2 and individual experts showed a median kappa value of 0.75 (0.50-0.92) for two groups and 0.50 (0.39-0.70) for four groups. Kappa values for the median expert score v Oasys-2 were 0.75 for two groups and 0.67 for four groups. Agreement was poor for records with intermediate probability, as defined by Oasys-2.

CONCLUSION

Considerable variation in agreement was seen in expert interpretation of occupational PEF records which may lead to inconsistencies in diagnosis of occupational asthma. There is a need for an objective scoring system which removes human variability, such as that provided by Oasys-2.

Management of solitary pulmonary nodules: how do thoracic computed tomography and guided fine needle biopsy influence clinical decisions?

BACKGROUND

Computed tomography (CT) and fine needle guided biopsy (FNB) are often used in the assessment of patients with lung nodules. The influence of these techniques on clinical decision making has not been quantified, especially for small solitary pulmonary nodules (SPN) where the probability of malignancy is lower. A study was undertaken to determine the effect of CT and FNB derived information on clinical decision making in patients with a solitary pulmonary nodule < or = 3 cm in diameter on initial chest radiography.

METHODS

Clinical, physiological, and outcome data on 114 patients with an SPN < or = 3 cm who had subsequent thoracic CT and FNB were extracted from the records of a specialist cardiorespiratory hospital in Auckland, New Zealand. Chest radiographs and CT scans were reported according to specified criteria by a thoracic radiologist. Computer generated summary sheets were used to present cases to each of six clinicians. Each case was presented three times: (1) with clinical data and chest radiograph only; (2) with the addition of the CT report; and (3) with all data including the result of the FNB. Clinicians were asked to specify their management on each occasion and to estimate the probability of the lesion being malignant. Reproducibility was assessed by re-evaluating 24 cases 1 month later.

RESULTS

33 (29%) nodules were benign, 35 (31%) nodules (malignant) were resected with negative node sampling, and 46 (40%) had a non-curative outcome (radiotherapy, incomplete resection, refused therapy). Intra-clinician decision making was consistent for all three levels of clinical data (median kappa values 0.79-0.89). Agreement between clinicians on the need for surgery was lowest with chest radiography alone (kappa=0.33), rose with CT information (kappa=0.44), and increased further with the addition of the FNB data (kappa=0.57). The proportion of successful decisions on surgical intervention (against the known outcome) increased with the addition of CT reports and further with FNB reports (p=0.006, Friedman's test). The major benefit of the information added by CT and FNB reports was a reduction in unnecessary surgery, especially when the clinical perception of pre-test probability of malignancy was intermediate (31-70%). FNB data contributed most to the benefit (p<0.001). The addition of CT and FNB was cost efficient and can be applied specifically to patients with a low or intermediate probability of malignancy.

CONCLUSION

Both CT and FNB make cost effective contributions to the clinical management of SPN < or = 3 cm in diameter by reducing unnecessary operations and increasing agreement between physicians on the need for surgery.

Management of solitary pulmonary nodules: how do thoracic computed tomography and guided fine needle biopsy influence clinical decisions?

BACKGROUND

Computed tomography (CT) and fine needle guided biopsy (FNB) are often used in the assessment of patients with lung nodules. The influence of these techniques on clinical decision making has not been quantified, especially for small solitary pulmonary nodules (SPN) where the probability of malignancy is lower. A study was undertaken to determine the effect of CT and FNB derived information on clinical decision making in patients with a solitary pulmonary nodule < or = 3 cm in diameter on initial chest radiography.

METHODS

Clinical, physiological, and outcome data on 114 patients with an SPN < or = 3 cm who had subsequent thoracic CT and FNB were extracted from the records of a specialist cardiorespiratory hospital in Auckland, New Zealand. Chest radiographs and CT scans were reported according to specified criteria by a thoracic radiologist. Computer generated summary sheets were used to present cases to each of six clinicians. Each case was presented three times: (1) with clinical data and chest radiograph only; (2) with the addition of the CT report; and (3) with all data including the result of the FNB. Clinicians were asked to specify their management on each occasion and to estimate the probability of the lesion being malignant. Reproducibility was assessed by re-evaluating 24 cases 1 month later.

RESULTS

33 (29%) nodules were benign, 35 (31%) nodules (malignant) were resected with negative node sampling, and 46 (40%) had a non-curative outcome (radiotherapy, incomplete resection, refused therapy). Intra-clinician decision making was consistent for all three levels of clinical data (median kappa values 0.79-0.89). Agreement between clinicians on the need for surgery was lowest with chest radiography alone (kappa=0.33), rose with CT information (kappa=0.44), and increased further with the addition of the FNB data (kappa=0.57). The proportion of successful decisions on surgical intervention (against the known outcome) increased with the addition of CT reports and further with FNB reports (p=0.006, Friedman's test). The major benefit of the information added by CT and FNB reports was a reduction in unnecessary surgery, especially when the clinical perception of pre-test probability of malignancy was intermediate (31-70%). FNB data contributed most to the benefit (p<0.001). The addition of CT and FNB was cost efficient and can be applied specifically to patients with a low or intermediate probability of malignancy.

CONCLUSION

Both CT and FNB make cost effective contributions to the clinical management of SPN < or = 3 cm in diameter by reducing unnecessary operations and increasing agreement between physicians on the need for surgery.

Questionnaire survey of male infertility in cystic fibrosis

Most male cystic fibrosis (CF) patients are infertile due to obstructive azospermia but little is known about the best time to counsel patients on infertility. All male patients attending the Adult Nottingham CF unit were invited to complete an anonymous questionnaire on infertility. The response rate was 60%. The median age that the patients first became aware of male infertility was 17 years (range 13-24) but the preferred age of receiving this information was 14 years (range 8-16). Patients first learnt about male infertility from the CF team (six patients), parents (five), from written information (two) or unexpectedly (five). Five out of 18 patients had undergone seminal analysis at a median age of 26 years but 17/18 patients felt that this should be offered routinely. Our survey has shown that patients would like infertility discussions at a younger age and routine seminal analysis.

Glucose uptake increases relative to oxygen consumption during short-term hibernation

BACKGROUND

Although glucose uptake is increased in chronically hypoperfused, viable myocardium, the dynamic changes in glucose uptake relative to oxygen consumption in "short-term" models of hibernation have not been fully explored.

METHODS

14 anesthetized swine were instrumented with an hydraulic occluder and flow probe on the proximal LAD artery. Blood flow was reduced approximately 30% for 1 hour. Myocardial blood flow and uptake of oxygen, free fatty acids, glucose and lactate were determined in the LAD region at baseline and at 10, 30, and 60 minutes of ischemia. Transmural biopsies for ATP and creatine phosphate (CP) were obtained in the LAD region prior to and at 15 and 45 minutes of ischemia. In 5 animals, glycogen was assayed at baseline and at the end of 60 minutes of ischemia.

RESULTS

In the LAD region, myocardial oxygen consumption was reduced from 2.06 +/- 0.16 micromol/min/gram to 1.46 +/- 0.13 micromol/min/gram (P < 0.05). By 15 minutes of ischemia, transmural creatine phosphate fell from 7.48 +/- 0.76 micromol/g-wet weight at baseline to 6.19 +/- 0.32 micromol/g-wet weight (P < 0.05) but normalized by 45 minutes of ischemia (7.39 +/- 0.56 micromol/g-wet weight; NS). Between 10 and 60 minutes of constant flow reduction, glucose uptake as a percentage of MVO2 increased from 3 +/- 2% to 10 +/- 2% (P < 0.05) while lactate uptake increased from -9 +/- 9% to -1 +/- 2% (P < 0.05). Glycogen decreased from 27.8 +/- 3.7 at baseline to 16.9 +/- 1.2 micromol/g-wet weight at end-ischemia.

CONCLUSIONS

In this model of short-term hibernation, glucose and lactate uptake increase relative to oxygen consumption during sustained ischemia, and temporally coincide with the recovery of bioenergetics. The findings are consistent with the notion that glycolytically derived ATP is important for the maintainance of energy supply during sustained ischemia.

Development of an expert system for the interpretation of serial peak expiratory flow measurements in the diagnosis of occupational asthma. Midlands Thoracic Society Research Group

If asthma is due to work exposures there must be a relation between these exposures and the asthma. Asthma causes airway hyperresponsiveness and obstruction; the obstruction can be measured with portable meters, which usually measure peak expiratory flow, or sometimes forced expiratory volume in 1 second (FEV1). These can be measured serially (for instance 2 hourly) over several weeks at and away from work. Once occupational asthma develops, the asthma will be induced by many non-specific triggers common to non-occupational asthma. The challenge is to identify changes in peak expiratory flow due to work among other non-occupational causes. Standard statistical tests have been found to be insensitive or non-specific, principally because of the variable period for deterioration to occur after exposure, and the sometimes prolonged time for recovery to occur, such that days away from work may initially have lower measurements than days at work. A computer assisted diagnostic aid (Oasys) has been developed to separate occupational from non-occupational causes of airflow obstruction. Oasys-2 is based on a discriminant analysis, and achieved a sensitivity of 75% and a specificity of at least 94%; therefore peak expiratory flow monitoring combined with Oasys-2 analysis is better to confirm than to exclude occupational asthma. A neural network version in development has improved on this. Both have been based on expert interpretation of peak flow measurements plotted as daily maximum, mean, and minimum, with the first reading at work taken as the first reading of the day. Oasys has been evaluated with independent criteria against measurements made in a wide range of occupational situations. Oasys is sufficiently developed to be the initial method for the confirmation, although less so for exclusion of occupational asthma.

How do general practitioners respond to reports of abnormal chest X-rays?

General practitioners (GPs) in the UK have long had direct access to hospital radiological services, which in theory shortens investigation time and improves the quality of service. Chest X-rays (CXRs) account for a substantial proportion of requests, and we investigated what happened when an abnormality was detected. In one year, 204 GPs in the Nottingham area requested CXRs in 605 patients. 362 were reported normal, 165 abnormal but hospital follow-up not indicated and 71 abnormal with radiological follow-up or hospital referral indicated (mass lesion suspicious of tumours 27, infective shadowing 35, other 9). 64 of the 71 were seen in hospital within three months, and in those with suspected cancer the median time to follow-up was 20 days. These results show that GPs do act on the results of abnormal CXRs, but only 37% of those with a mass suspicious of cancer were seen in hospital within two weeks as recommended by the British Thoracic Society. Time might be saved if GPs agreed to direct referral from the radiology department to respiratory physicians.

Comparison of two new methods for the measurement of lung volumes with two standard methods

BACKGROUND

The two most commonly used methods for the measurement of lung volumes are helium dilution and body plethysmography. Two methods have been developed which are both easier and less time consuming to perform. Mathematical modelling uses complex calculations from the flow-volume loop to derive total lung capacity (TLC), and the nitrogen balance technique uses nitrogen from the atmosphere to calculate lung volume in a similar way to helium dilution. This study was designed to compare the two new methods with the two standard methods.

METHODS

Sixty one subjects were studied, 23 with normal lung function, 17 with restrictive airway disease, and 21 with obstructive ventilatory defects. Each subject underwent repeated measurements of TLC by each of the four methods in random order. Reproducible values were obtained for each method according to BTS/ARTP guidelines. Bland-Altman plots were constructed for comparisons between the methods and paired t tests were used to assess differences in means.

RESULTS

Bland-Altman plots showed that the differences between body plethysmography and helium dilution fell into clinically acceptable ranges (agreement limits +/-0.9 l). The agreement between mathematical modelling or the nitrogen balance technique and helium dilution or body plethysmography was poor (+/-1.8-3.4 l), especially for subjects with airflow obstruction.

CONCLUSIONS

Neither of the new methods agrees sufficiently with standard methods to be useful in a clinical setting.

Comparative clinical and physiological features of Maori, Pacific Islanders and Europeans with sleep related breathing disorders

Recent studies have suggested that there is a familial association of sleep apnoea syndrome and that this is not entirely explained by inheritance of known risk factors. Maori (M) and Pacific Islanders (PI) have many of the body habitus features associated with sleep apnoea and therefore might be expected to exhibit more severe disease than Europeans (E).

OBJECTIVE

To compare the clinical and physiological characteristics of the different ethnic groups and to determine if race was an independent predictor of severity of sleep apnoea.

METHODOLOGY

A prospective evaluation of patients attending the Sleep Disordered Breathing Clinic which serves the whole of Auckland (population 1.1 million), New Zealand was conducted for the period July 1994 to August 1995. The evaluation included history including a 26 question questionnaire, Epworth sleepiness score, examination, and where indicated, full polysomnography.

RESULTS

A total of 233 patients (154 E, 48 M and 33 PI), underwent full polysomnography. Forty-one (85%) of the M and 31 (94%) of PI had obstructive or mixed sleep apnoea compared with only 74 (49%) of the E (P < 0.0001; chi 2). There were few racial differences in the responses to the sleep questionnaire. M and PI were shown to have much greater neck and waist circumference and body mass indices. Severity parameters (apnoea-hypopnoea index, wake and minimum oxygen saturation, and apnoea duration) were greater for both M and PI compared with E (P < 0.001; Mann-Whitney U-test). Stepwise regression identified neck size, body mass index and age as independent predictors of severity.

CONCLUSION

When other factors were controlled for, race was not an important independent predictor of severity of sleep apnoea.

Effect of two types of mandibular advancement splints on snoring and obstructive sleep apnoea

Snoring and obstructive sleep apnoea (OSA) both seem at least to be associated with narrowing of the upper airway and sleep-induced loss of muscle-tone. Mandibular advancement splints (MAS) have been proposed as a relatively simple method to increase oro- and hypo-pharyngeal dimensions thereby increasing the size of the airway. However, data on their effectiveness are conflicting and there are no clear indications as to which design is most effective or when they should be used. The effects of two designs of splint (types A and B) have been evaluated in 14 and nine subjects, respectively, using the Epworth Sleepiness Score (ESS) and domiciliary sleep monitoring on separate nights. Both splints reduced the median ESS (type A from 12 to 4.5; P = 0.003, type B from 7 to 4; P = 0.005). The apnoea-hypopnoea index was not affected by type A, but was reduced from 7.1 to 0.8; P = 0.005 by type B splints. There was evidence of a small improvement in overnight oxygen saturation for type B splints (P = 0.02). The splints were well tolerated and continued to be used nightly by 18 subjects. Mandibular advancement splints may offer a simple and effective alternative for the treatment of snoring and mild OSA in selected patients. Splint design may have considerable bearing on efficacy.

Coronary bypass grafting for single-vessel coronary artery disease: a 17-year review with short- and long-term follow-up

STUDY OBJECTIVES

We reviewed our short- (30 days) and long-term (up to 17 years) experience with surgical revascularization for patients with angiographically documented isolated single-vessel coronary artery disease.

DESIGN

Retrospective study of single-vessel coronary artery bypass procedures performed from January 1980 through June 1996. During this time, 100 consecutive patients underwent a single-vessel coronary artery bypass. All patients were men with a mean age of 59+/-9 years (range, 35 to 78 years) and a mean ejection fraction of 56+/-8% (range, 35 to 77%). The vessels bypassed included the left anterior descending in 66 (66%), right coronary artery in 31 (31%), and the obtuse marginal in 3 (3%).

RESULTS

Short-term results reveal no deaths and six (6.0%) complications. Long-term follow-up by chart review and telephone survey was available in 87 (87%) patients at a mean of 46.9 months (range, 12 to 151 months). Cumulative freedom from angina and repeated revascularization was 93% and 98% at 1 year and 55% and 81% at 10 years, respectively (Kaplan-Meier).

CONCLUSION

Single-vessel coronary artery bypass for isolated single-vessel disease can be performed with minimal morbidity and no mortality and provides excellent long-term relief of angina.

Stress and illness in adolescence: issues of race and gender

There is an abundance of information on the association between stressful life events and illness within the adult population. In contrast, research on this relationship among adolescents is limited. This study evaluated the role of individual differences (gender and race) on the stress-illness relationship within the adolescent population. Participants were 119 adolescents (54 females and 65 males), recruited from two public high schools located in the southeast, who were administered four questionnaires designed to measure levels of stress, anxiety, and illness. Overall, correlational analysis revealed that stress and anxiety were positively correlated with reported illness. However, racial and gender differences did emerge. Although no gender differences were found with regard to the experience of stress, African-American athletes reported a higher frequency of stressful life events than did their Euro-American counterparts. Further, African-American adolescents reported a lower frequency of illness than did the Euro-Americans. Females reported more illnesses than did males. Possible explanations for individual differences in reported stress and illness are discussed.

The effects of voluntary exercise and immobilization on humoral immunity and endocrine responses in rats

This research examined the effect of type of stressor (physical vs. psychological) on humoral immunity and neuroendocrine responses in male and female rats. Eighty adult Sprague-Dawley rats were assigned to one of the four stress conditions (n = 20 animals/group): 1. Voluntary running (high physical/low psychological stress); 2. immobilization (low physical/high psychological stress); 3. mixed stress (running and immobilization); and 4. cage control group. The experimental manipulations were conducted over a 6-week period for 4 h/day. Five weeks after the start of the study, all animals were immunized with 1 ml of a 10% suspension of sheep red blood cells (SRBC) in saline and sacrificed 1 week later. Data analyses revealed no main effect of stress on any of the immune or endocrine parameters. However, strong gender differences emerged within the stress conditions on these physiological parameters. The stressed female rats displayed an enhanced antibody response to SRBC and a higher percentage of peripheral blood lymphocytes than their male counterparts. However, there were no significant differences between the male and female control animals with respect to these variables. Female rats consistently displayed elevated levels of plasma corticosterone and adrenal norepinephrine across all conditions. In addition, female rats displayed heavier relative organ weights (adrenal and spleen). Taken together, the notion of differential immunity with respect to physical or psychological stress is not supported by the present study.