Barriers to early diagnosis of cancer in primary care: a needs assessment of GPs

This is the first needs assessment of general practitioners (GPs) in relation to early detection of cancer in the Republic of Ireland. Data was collected using focus groups with 47 GPs and a national survey of 929 GPs. Overall,74.6% of survey respondents had >10 years experience in general practice and 22.7% were single handed. Distance from the practice to the nearest hospital to which they could refer patients for assessment of suspected cancer was <5 miles for 53.3% of GPs. The principle barriers identified were not confined to early diagnosis but apply to the diagnosis of cancer at any stage. These included delayed patient presentation, lack of direct GP access to investigations, difficulty with hospital referral, lack of clear recommendations for screening, poor communication with hospital services, inequitable access to hospital services and a need for further education and clinical practice guidelines. The barriers identified have serious implications for early detection of cancer in primary care and are remedial.     

Soft-tissue detectability in cone-beam CT: evaluation by 2AFC tests in relation to physical performance metrics

Soft-tissue detectability in cone-beam computed tomography (CBCT) was evaluated via two-alternative forced-choice (2AFC) tests. Investigations included the dependence of detectability on radiation dose, the influence of the asymmetric three-dimensional (3D) noise-power spectrum (NPS) in axial and sagittal or coronal planes, and the effect of prior knowledge on detectability. Custom-built phantoms (approximately 15 cm diameter cylinders) containing soft-tissue-simulating spheres of variable contrast and diameter were imaged on an experimental CBCT bench. The proportion of correct responses (Pcorr) in 2AFC tests was analyzed as a figure of merit, ideally equal to the area under the receiver operating characteristic curve. Pcorr was evaluated as a function of the sphere diameter (1.6-12.7 mm), contrast (20-165 HU), dose (1-7 mGy), plane of visualization (axial/sagittal), apodization filter (Hanning and Ram-Lak), and prior knowledge provided to the observer [ranging from stimulus known exactly (SKE) to stimulus unknown (SUK)]. Detectability limits were characterized in terms of the dose required to achieve a given level of Pcorr (e.g., 70%). For example, a 20 HU stimulus of diameter down to approximately 6 mm was detected with Pcorr 70% at dose > or =2 mGy. Detectability tended to be greater in axial than in sagittal planes, an effect amplified by sharper apodization filters in a manner consistent with 3D NPS asymmetry. Prior knowledge had a marked influence on detectability--e.g., Pcorr for a approximately 6 mm (20 HU) sphere was approximately 55%-65% under SUK conditions, compared to approximately 70%-85% for SKE conditions. Human observer tests suggest practical implications for implementation of CBCT: (i) Detectability limits help to define minimum-dose imaging techniques for specific imaging tasks; (ii) detectability of a given structure can vary between axial and sagittal/coronal planes, owing to the spatial-frequency content of the 3D NPS in relation to the imaging task; and (iii) performance under SKE conditions (e.g., image guidance tasks in which lesion characteristics are known) is maintained at a lower dose than in SUK conditions (e.g., diagnostic tasks in which lesion characteristics are unknown).     

Ascertainment Through Family History of Disease Often Decreases the Power of Family-based Association Studies

Selection of cases with additional affected relatives has been shown to increase the power of the case-control association design. We investigated whether this strategy can also improve the power of family-based association studies that use the transmission disequilibrium test (TDT), while accounting for the effects of residual polygenic and environmental factors on disease liability. Ascertainment of parent-offspring trios conditional on the proband having affected first-degree relatives almost always reduced the power of the TDT. For many disease models, this reduction was quite considerable. In contrast, for the same sample size, designs that analyzed more than one affected offspring per family often improved power when compared to the standard parent-offspring trio design. Together, our results suggest that (1) residual polygenic and environmental influences should be considered when estimating the power of the TDT for studies that ascertain families with multiple affected relatives; (2) if trios are selected conditional on having additional affected offspring, then it is important to genotype and include in the analysis the additional siblings; (3) the ascertainment strategy should be considered when interpreting results from TDT analyses. Our analytic approach to estimate the asymptotic power of the TDT is implemented online at http://pngu.mgh.harvard.edu/∼purcell/gpc/. Edited by David Allison     

Junior staffing changes and the temporal ecology of adverse incidents in acute psychiatric wards

AIM: This paper reports an examination of the relationship between adverse incident rates, the arrival of new junior staff on wards, and days of the week on acute psychiatric wards. BACKGROUND: Incidents of violence, absconding and self-harm in acute inpatient services pose risks to patients and staff. Previous research suggests that the arrival of inexperienced new staff may trigger more adverse incidents. Findings on the relationship between incidents and the weekly routine are inconsistent. METHOD: A retrospective analysis was conducted of formally reported incident rates, records of nursing student allocations and junior doctor rotation patterns, using Poisson Regression. Variance between days of the week was explored using contingency table analysis. The data covered 30 months on 17 psychiatric wards, and were collected in 2002-2004. FINDINGS: The arrival of new and inexperienced staff on the wards was not associated with increases in adverse incident rates. Most types of incidents were less frequent at weekends and midweek. Incident rates were unchanged on ward-round days, but increased rates were found on the days before and after ward rounds. CONCLUSION: Increased patient tension is associated with raised incident rates. It may be possible to reduce incident rates by moderating stimulation in the environment and by mobilizing support for patients during critical periods.     

Comparison of new and 3-month-old brush heads in the removal of plaque using a powered toothbrush

AIM: To compare the effectiveness of new and 3-month-old worn brush heads in plaque removal using a rotation-oscillation-powered toothbrush. MATERIAL AND METHODS: A single examiner blinded, randomized, cross-over study was conducted in which 34 adults attended the clinic on two occasions following 48-h periods of no oral hygiene. Following plaque scoring, subjects brushed for 2 min. with either a new brush or a brush they had used for 3 months and plaque was then re-scored. Bristle wear was assessed by measuring brushing surface areas on digital images. RESULTS: The mean plaque score percentage reductions with new brush heads were not significantly different from those achieved with 3-month-old heads for total surfaces (new=38.1%; worn=37.1%; p=0.83) and approximal surfaces (new=31.3%; worn=30.8%; p=0.9). Brushing surface area increases of the 3-month-old heads ranged from 0% to 135% (mean 26.9%). Compared with new brush heads, no significant differences were found for plaque score reductions for heads with minor, moderate or marked wear. CONCLUSION: Rotation-oscillation-powered toothbrushes with 3-month-old brush heads exhibiting various degrees of wear were as effective as new brush heads in plaque removal. Bristle age and wear on a powered toothbrush may not impede the effectiveness of plaque removal.     

Genetic polymorphisms in NQO1 and SOD2: Interactions with smoking,schistosoma infection,and bladder cancer risk in Egypt

BackgroundBladder cancer is the most prevalent form of cancer in men among Egyptians, for whom tobacco smoke exposure and Schistosoma haematobium (SH) infection are the major risk factors. We hypothesized that functional polymorphisms in NAD(P)H:quinone oxidoreductase 1 (NQO1) and superoxide dismutase 2 (SOD2), modulators of the effects of reactive oxidative species, can influence an individual's susceptibility to these carcinogenic exposures and hence the risk of bladder cancer.MethodsWe assessed the effects of potential interactions between functional polymorphisms in the NQO1 and SOD2 genes and exposure to smoking and SH infection on bladder cancer risk among 902 cases and 804 population-based controls in Egypt. We used unconditional logistic regression to estimate the odds ratios (OR) and confidence intervals (CI) 95%.ResultsWater pipe and cigarette smoking were more strongly associated with cancer risk among individuals with the TT genotype for SOD2 (OR [CI 95%] = 4.41 [1.86–10.42]) as compared with those with the CC genotype (OR [CI 95%] = 2.26 [0.97–6.74]). Conversely, the risk associated with SH infection was higher among the latter (OR [CI 95%] = 3.59 [2.21–5.84]) than among the former (OR [CI 95%] = 1.86 [1.33–2.60]). Polymorphisms in NQO1 genotype showed a similar pattern, but to a much lesser extent. The highest odds for having bladder cancer following SH infection were observed among individuals with the CC genotypes for both NQO1 and SOD2 (OR [CI 95%] = 4.41 [2.32–8.38]).ConclusionOur findings suggest that genetic polymorphisms in NQO1 and SOD2 play important roles in the etiology of bladder cancer by modulating the effects of known contributing factors such as smoking and SH infection.