Accuracy and cost-effectiveness of dynamic contrast-enhanced CT in the characterisation of solitary pulmonary nodules-the SPUtNIk study.

INTRODUCTION: Solitary pulmonary nodules (SPNs) are common on CT. The most cost-effective investigation algorithm is still to be determined. Dynamic contrast-enhanced CT (DCE-CT) is an established diagnostic test not widely available in the UK currently. METHODS AND ANALYSIS: The SPUtNIk study will assess the diagnostic accuracy, clinical utility and cost-effectiveness of DCE-CT, alongside the current CT and 18-flurodeoxyglucose-positron emission tomography) (18FDG-PET)-CT nodule characterisation strategies in the National Health Service (NHS). Image acquisition and data analysis for 18FDG-PET-CT and DCE-CT will follow a standardised protocol with central review of 10% to ensure quality assurance. Decision analytic modelling will assess the likely costs and health outcomes resulting from incorporation of DCE-CT into management strategies for patients with SPNs. ETHICS AND DISSEMINATION: Approval has been granted by the South West Research Ethics Committee. Ethics reference number 12/SW/0206. The results of the trial will be presented at national and international meetings and published in an Health Technology Assessment (HTA) Monograph and in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ISRCTN30784948; Pre-results.

Interval cancers in the National Health Service Breast Screening Programme.

The National Health Service (NHS) Breast Screening Programme defines objectives with acceptable and, where possible, achievable standards. This paper examines the problem of interval cancers. Slopes due to shrinkage of primary breast cancers in response to primary systemic therapy are used as surrogates for growth slopes. From the distribution of these slopes the proportion of tumours which might reach particular sizes in any time interval may be estimated. For specific differences in size between screen and clinical detection levels the number of interval cancers which could appear in 1, 2 and 3 years after screening is estimated. The justification for these predictions is evaluated. The literature in relation to growth is reviewed; we add three growth slopes from our own measurements. The range of volume doubling times and volume halving times is the same whereas the mean value derived from the literature is about 90 days in contrast to only 26 days for inferred growth rates. Because of the difficulties inherent in the measurement of growth, it is concluded that the literature defines the left half of a distribution; the right hand side is completed by shrinkage data. The observed rates for interval cancers from different sources vary widely; there is an underlying assumption that interval cancers are an index of failure. These calculations suggest that there is an irreducible minimum of interval cancers, which will depend upon the screening interval and the size at which tumours are detected. The interval cancers will contain more poorly differentiated tumours. The anticipated achievable standards appear to be over optimistic.

Diagnostic image quality of mobile neonatal chest X-rays and the radiation exposure incurred.

A study was undertaken to identify the variation of entrance skin doses (ESDs) in mobile neonatal chest radiography with regard to the European Commission (EC) reference dose and to examine potential relationships with image quality and radiographic techniques. Five sites from the former North West Thames region participated. All mobile neonatal radiographic techniques were surveyed. Dose-area product per examination was directly measured and the ESD calculated. Image quality criteria were developed from those published by the EC. Image quality was graded by two independent observers. Over the five sites, 144 examinations were recorded. Calculated ESDs ranged up to 160 microGy, with an appreciable variation not only between sites but also within sites. A clear relationship between actual rather than nominal speed and dose over all sites was demonstrated (r = -0.95, p = 0.013). No correlation between image quality and dose was noted (r = -0.044, p = 0.665). Neonatal imaging systems at participating sites, within the North Thames region, comply with EC guidelines on patient dose and image quality for mobile chest X-rays. Significant variation in ESDs was encountered between sites with no discernible relationship with image quality or the employed radiographic techniques as described by the EC. The strong inverse relationship between ESDs and actual rather than nominal speed suggests a neglected aspect of radiation protection.

Does breast cancer grade worsen with time? Evidence from breast screening.

It has been suggested that alteration of the distribution of histological grades, that has been found in screening programmes, is evidence for progression in histological grade with increasing size. A predictive model, that was based upon estimated growth data from an unselected series of 98 new primary breast cancers, is used to estimate the proportions of tumors that would be diagnosed according to limiting screen diagnostic and clinical diagnostic sizes after particular screening intervals; windows of opportunity are created. The results show that the limitations imposed by time and size criteria alter the distribution of growth rates of tumours that may appear in the windows. Small screen diagnostic sizes and short screening intervals allow only the most rapidly growing tumours to reach large sizes. This produces an apparent association of grade 3 tumours with large size. Interval cancers are also likely to be more rapidly growing while the more slowly growing tumours will be diagnosed at the subsequent screen to produce a spurious association of slowly growing grade 1 tumours with small size. We conclude that the evidence from screening does not support the thesis of progression of histological grade with the ageing of the tumour, since the changes that have been observed are predictable from a simple model based upon patterns of tumour growth rates and the relationships between growth rate and histology.