Strategies for Colorectal Cancer Screening

The incidence of colorectal cancer (CRC) is increasing worldwide. CRC has high mortality when detected at advanced stages, yet it is also highly preventable. Given the difficulties in implementing major lifestyle changes or widespread primary prevention strategies to decrease CRC risk, screening is the most powerful public health tool to reduce mortality. Screening methods are effective but have limitations. Furthermore, many screen-eligible persons remain unscreened. We discuss established and emerging screening methods, and potential strategies to address current limitations in CRC screening. A quantum step in CRC prevention might come with the development of new screening strategies, but great gains can be made by deploying the available CRC screening modalities in ways that optimize outcomes while making judicious use of resources

Theory and analysis of electrode size optimization for capacitive microfabricated ultrasonic transducers

Cataloged from PDF version of article.Theoretical analysis and computer simulations of capacitive microfabricated ultrasonic transducers indicate that device performance can be optimized through judicious patterning of electrodes. The conceptual basis of the analysis is that electrostatic force should be applied only where it is most effective, such as at the center of a circular membrane. If breakdown mechanisms are ignored, an infinitesimally small electrode with an infinite bias voltage results in the optimal transducer, A more realistic design example compares the 3-dB bandwidths of a fully metalized transducer and a partially metalized transducer, each tuned with a lossless Butterworth network. It is found that the bandwidth of the optimally metalized device is twice that of the fully metalized device

Helicobacter pylori test-and-treat intervention compared to usual care in primary care patients with suspected peptic ulcer disease in the United States

The Helicobacter pylori ( H. pylori ) “test-and-treat” strategy in uninvestigated dyspepsia is an effective alternative to prompt endoscopy. Our aims were to determine whether the combination of an educational session and availability of office-based H. pylori testing (test-and-treat intervention [TTI]) increases use of the test-and-treat strategy by primary care practitioners and whether it improves patient outcomes. Methods : We conducted a 1-yr prospective trial of patients with suspected peptic ulcer disease in six primary care centers, three with TTI and three designated as usual care controls (UCC). Results : H. pylori testing was performed in 81% of 54 TTI patients and in 49% of 39 UCC patients ( p = 0.004). TTI and UCC patients had similar gastroenterology referral rates (24% vs 33%, p = 0.33), endoscopy or upper GI radiography rates (30% vs 31%, p = 0.91), and primary care visits per patient (3.1 ± 2.8 vs 3.1 ± 2.6, p = 0.92). TTI patients were less likely than UCC patients to receive repeated antisecretory medication prescriptions (35% vs 66%, p = 0.003). Symptomatic status at 1 yr and satisfaction with medical care did not differ between groups. Median (and interquartile range) annualized disease-related expenditures per patient were $454 ($162–932) for TTI and $576 ($327–1435) for UCC patients ( p = 0.17). Conclusions : The combination of an educational session and availability of office-based H. pylori testing may increase acceptance of the test-and-treat strategy by primary care providers. It remains to be determined whether increased use of the test-and-treat strategy yields significant improvements in clinical and economic outcomes compared to usual care.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74830/1/j.1572-0241.2002.07118.x.pd

Rates and Predictors of Colorectal Cancer Screening

Introduction: Despite widespread recommendations for colorectal cancer screening, the U.S. screening rate is low. The objectives of this study were to describe the rates and predictors of colorectal cancer screening use by examining groups in two categories — 1) those who have ever been screened and 2) those with up-to-date screening — and to assess whether trends and predictors change over time. Methods: We analyzed data from the 2000 and 2003 National Health Interview Surveys about the use of fecal occult blood tests, sigmoidoscopies, and colonoscopies for adults aged 50 years and older and without a history of colorectal cancer (N = 11,574 in 2000 and N = 11,779 in 2003). Results: Rates in the 2000 study population of those who have ever been screened for colorectal cancer (53%) had increased in the 2003 study population (55%) as had the rates in the 2003 study population of those with up-to-date colorectal screening (53%) compared with the rates in the 2000 study population (38%). Among those who were ever screened, 76% were up-to-date with screening in 2003, compared with 68% in 2000. There was increased use of colonoscopies but decreased use of fecal occult blood tests and sigmoidoscopies. Individuals were more likely to be up-to-date with screening if they had higher income, higher education, insurance coverage, a usual source of care, and a dental visit in the last year than if these predictors were not evident. Since 2000, these predictors of colorectal cancer screening use have remained stable. Conclusion: Although there has been relatively limited success in increasing overall screening, it is encouraging that most people in the group of those who have ever been screened are up-to-date with colorectal cancer screening. Predictors for colorectal screening were stable over time despite changes in screening policies and rates. Further research is needed to uncover barriers to colorectal cancer screening

Surface micromachined capacitive ultrasonic transducers

Cataloged from PDF version of article.The current state of a novel technology, surface microfabricated ultrasonic transducers, is reported. Experiments demonstrating both air and water transmission are presented. Air-coupled longitudinal wave transmission through aluminum is demonstrated, implying a 110 dB dynamic range for transducers at 2.3 MHz in air. Water transmission experiments from 1 to 20 MHz are performed, with a measured 60 dB SNR at 3 MHz. A theoretical model is proposed that agrees well with observed transducer behavior. Most significantly, the model is used to demonstrate that microfabricated ultrasonic transducers constitute an attractive alternative to piezoelectric transducers in many applications

Reappraisal of non-invasive management strategies for uninvestigated dyspepsia: a cost-minimization analysis

Background : The benefits of the Helicobacter pylori test-and-treat strategy are attributable largely to the cure of peptic ulcer disease while limiting the use of endoscopy. Aim : To reappraise the test-and-treat strategy and empirical proton pump inhibitor therapy for the management of uninvestigated dyspepsia in the light of the decreasing prevalence of H. pylori infection, peptic ulcer disease and peptic ulcer disease attributable to H. pylori . Methods : Using a decision analytical model, we estimated the cost per patient with uninvestigated dyspepsia managed with the test-and-treat strategy ($25/test; H.pylori treatment,$200) or proton pump inhibitor ($90/month). Endoscopy ($550) guided therapy for persistent or recurrent symptoms. Results : In the base case (25% H. pylori prevalence, 20% likelihood of peptic ulcer disease, 75% of ulcers due to H.pylori ), the cost per patient is $545 with the test-and-treat strategy and$529 with proton pump inhibitor, and both strategies yield similar clinical outcomes at 1 year. H. pylori prevalence, the likelihood of peptic ulcer disease and the proportion of ulcers due to H.pylori are important determinants of the least costly strategy. At an H. pylori prevalence below 20%, proton pump inhibitor is consistently less costly than the test-and-treat strategy. Conclusions : As the H. pylori prevalence, the likelihood of peptic ulcer disease and the proportion of ulcers due to H. pylori decrease, empirical proton pump inhibitor becomes less costly than the test-and-treat strategy for the management of uninvestigated dyspepsia. Given the modest cost differential between the strategies, the test-and-treat strategy may be favoured if patients without peptic ulcer disease derive long-term benefit from H.pylori eradication.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75747/1/j.1365-2036.2002.01306.x.pd

As tests evolve and costs of cancer care rise: reappraising stool-based screening for colorectal neoplasia

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73533/1/j.1365-2036.2008.03632.x.pd

Air-coupled, focused ultrasonic dispersion spectrum reconstruction in plates

This paper presents and demonstrates a noncontact method for measuring the Lamb wave dispersion spectrum of a plate. Noncontact air-coupled source and receive transducers are used with line-focus mirrors and 50–700 kHz broadband apparatus for simultaneous measurement over a broad spectrum of refractive angles and multiple guided modes. Broadband, wide-angle wave forms are measured as a function of position. The Fourier transform of these wave forms from the t – x domain to the v – k domain gives an approximate spectrum of the dispersion relation. We measure the dispersion spectra of Lucite™, aluminum, balsa wood, and a carbon fiber epoxy laminate, and show that the measured spectra agree well with the dispersion relation calculated from Lamb wave theory

Risk Factors for Metachronous Colorectal Cancer or Advanced Adenomas After Endoscopic Resection of Highrisk Adenomas

Background & aims: Among the characteristics of high-risk adenomas (HRAs), some may predict a higher risk of metachronous advanced lesions. Our aim was to assess which HRA characteristics are associated with high risk of metachronous colorectal cancer (CRC) or advanced adenomas (AAs). Methods: We systematically searched Pubmed, EMBASE, and Cochrane for cohort studies and clinical trials of CRC or AA incidence at surveillance stratified by baseline lesion size, histology, and multiplicity. We calculated pooled relative risks (RRs) using a random-effects model. Heterogeneity was assessed with the I2 statistic. Results: Fifty-five studies were included, with 936,540 patients with mean follow-up 5.4 ± 2.9 years. CRC incidence per 1000 person-years was 2.6 (2.1-3.0) for adenomas ≥20 mm, 2.7 (2.2-3.2) for high-grade dysplasia (HGD), 2.0 (1.8-2.3) for villous component, 0.8 (0.1-1.4) for ≥5 adenomas, 1.0 (0.7-1.2) for ≥3 adenomas. Metachronous CRC risk was higher in adenomas ≥20 mm vs 10 to 19 mm (RR, 2.08; 95% confidence interval [CI], 1.20-3.61), HGD vs low-grade dysplasia (RR, 2.89; 95% CI, 1.88-4.44), villous vs tubular (RR, 1.75; 95% CI, 1.33-2.31). No significant differences in CRC risk were found in ≥3 adenomas vs 1 to 2 (RR, 1.24; 95% CI, 0.84-1.83), nor in ≥5 adenomas vs 3 to 4 (RR, 0.79; 95% CI, 0.30-2.11). Compared with normal colonoscopy, RR for CRC risk was 2.61 (95% CI, 2.06-3.32) for ≥10mm, 6.62 (95% CI, 4.60-9.52) for HGD, 3.58 (95% CI, 2.24-5.73) for villous component, and 2.03 (95% CI, 1.40-2.94) for ≥3 adenomas. Similar trends were seen for metachronous AAs. Conclusion: Metachronous CRC risk is highest in patients with baseline adenomas with ≥20 mm or HGD. Multiplicity does not seem to be associated with substantially higher CRC risk in the near term