How much does colonoscopy reduce colon cancer mortality?

Multi-scale, multi-dimensional binocular endoscopic image depth estimation network

During invasive surgery, the use of deep learning techniques to acquire depth information from lesion sites in real-time is hindered by the lack of endoscopic environmental datasets. This work aims to develop a high-accuracy three-dimensional (3D) simulation model for generating image datasets and acquiring depth information in real-time. Here, we proposed an end-to-end multi-scale supervisory depth estimation network (MMDENet) model for the depth estimation of pairs of binocular images. The proposed MMDENet highlights a multi-scale feature extraction module incorporating contextual information to enhance the correspondence precision of poorly exposed regions. A multi-dimensional information-guidance refinement module is also proposed to refine the initial coarse disparity map. Statistical experimentation demonstrated a 3.14% reduction in endpoint error compared to state-of-the-art methods. With a processing time of approximately 30fps, satisfying the requirements of real-time operation applications. In order to validate the performance of the trained MMDENet in actual endoscopic images, we conduct both qualitative and quantitative analysis with 93.38% high precision, which holds great promise for applications in surgical navigation.

Knowledge and awareness about colorectal cancer and barriers to its screening among a sample of general public in Saudi Arabia

INTRODUCTION

The present study investigated knowledge, awareness, and barriers to colorectal cancer (CRC) screening from a sample of the general population in Saudi Arabia.

METHODS

This cross-sectional study was conducted between August 2022 and January 2023 among a sample of the general population in Jeddah, Saudi Arabia. The questionnaire consisted of demographics, knowledge and awareness, and questions about CRC screening barriers.

RESULTS

A total of 1105 adults belonged to the general public [505 females (45.7%) and 600 males (54.3%)] recruited in this survey. The mean age of the respondents was 39.79±12.49. The internet was the primary source of CC information for most participants, 661(59.8%). Gender-wise comparison of general public responses regarding CRC knowledge and awareness and barriers to screening showed a mixed response. Analysis of participants' knowledge regarding CRC and its risk factors and warning signs showed that 356(32.2%) people believed that the best age for the CRC test is 41-50 years, and 285(25.8%) responded they don't know. Almost half of the participants, 539(48.8%), were not interested in attending awareness seminars about CRC, while 371(33.6%) were interested in attending awareness seminars about CRC. Only one-third of the respondents, 368(33.3%), knew of any tests or examinations used to detect CRC. Participants' perceptions about colonoscopy-related and FOBT-related barriers to CRC screening disclosed that these are time-consuming, expensive, painful, embarrassing, etc.

CONCLUSION

Insufficient information, poor awareness, and several assumed barriers to CRC screening were found among study participants. There is a need to close knowledge gaps and offer them comprehensive information regarding CRC, as well as the availability and benefits of screening. In this aspect, social media can be extremely beneficial.

piRNA-823 Is a Unique Potential Diagnostic Non-Invasive Biomarker in Colorectal Cancer Patients

Early detection of colorectal cancer (CRC) is the most important factor in deciding its prognosis, so the need to develop an accurate screening test is a must. P-element induced wimpy testis (PIWI) RNA-823 (piR-823) is one of the first piRNAs recognized to be linked to malignancy. We aimed to investigate the expression levels of piR-823 in both serum and tissues of colorectal cancer patients and the ability to use its serum level as a non-invasive diagnostic biomarker to detect colorectal cancer. We determined piR-823 expression levels in 84 serum samples of CRC patients, 75 serum samples of healthy controls, and biological specimens obtained from the 84 patients with colorectal cancer from both the tumor tissues and the normal neighboring tissues using quantitative real-time reverse transcriptase-PCR. We showed that piR-823 had significantly higher serum and tissue expression levels in CRC patients compared to the controls. We observed a significant positive correlation between piR-823 serum levels and the staging of CRC, with significantly higher levels exhibiting advanced stages of CRC (III and IV). This translates into poorer differentiation and lymph node metastasis. The receiver operating characteristic curve (ROC curve) test showed 83.3% sensitivity and 89.3% specificity at a cut-off value of >5.98-fold change, with an area under the curve of 0.933 (p < 0.0001) concerning the ability of piR-823 in diagnosing patients with colorectal carcinoma. piR-823 expression is upregulated in colorectal cancer patients’ serum and tissues, and it can be used as a diagnostic noninvasive biomarker for CRC.

Colon Cancer: A Clinician's Perspective in 2019

Colon cancer is a common preventable cancer. With the adoption of widespread colon cancer screening in the developed countries, the incidence and mortality of colon cancer have decreased in the targeted population. But unfortunately, the incidence and mortality of colorectal cancer (CRC) have been increasing over the last 25 years in the young adults below the age of 50. There is disparity in benefit, i.e. reduction in risk of death between right-sided and left-sided colon cancer by screening colonoscopy. The reason could be multifactorial and various measures have been taken to decrease this disparity. Although most of the screened populations are average risk individuals, a minority of the population have various risk factors for developing colon cancer and need to follow specific colon cancer screening guidelines. Gene mutations (adenomatous polyposis coli (APC), deleted in colon cancer (DCC), K-ras, p53, B-Raf proto-oncogene serine/threonine kinase (BRAF), mismatch repair genes) and microsatellite instability lead to the development of colon cancer. Although various non-invasive methods of colon cancer screening are now available, colonoscopy remains the gold standard of colon cancer screening and adenoma detection rate is now being used as the quality metrics in screening colonoscopy. Although Multi-Society Task Force (MSTF) and American College of Physicians (ACP) recommend initiating screening colonoscopy at age 50 years in all individuals except African Americans who should begin screening colonoscopy at age 45 years, the American Cancer Society (ACS) recommends initiating screening colonoscopy at age 45 years in all individuals irrespective of race and ethnicity. Low-volume split-dose prep has been found to be as effective as high-volume split-dose prep and more tolerable to patients with increased compliance. Boston bowel preparation scale is recommended to measure the quality of colon cleansing. CRC is curative if it is diagnosed at an early stage but various palliative treatment options (endoscopic, oncologic and surgical) are available in advanced stages of this cancer. Adequate number of lymph node assessment during surgery is essential in accurate staging of CRC. Checkpoint inhibitors have been found to have dramatic response and durable clinical benefit in dMMR/MSI-H metastatic CRC. Different genetic and immune-oncologic research trials are ongoing for early detection and better management of CRC.

Deep learning and conditional random fields-based depth estimation and topographical reconstruction from conventional endoscopy

Colorectal cancer is the fourth leading cause of cancer deaths worldwide and the second leading cause in the United States. The risk of colorectal cancer can be mitigated by the identification and removal of premalignant lesions through optical colonoscopy. Unfortunately, conventional colonoscopy misses more than 20% of the polyps that should be removed, due in part to poor contrast of lesion topography. Imaging depth and tissue topography during a colonoscopy is difficult because of the size constraints of the endoscope and the deforming mucosa. Most existing methods make unrealistic assumptions which limits accuracy and sensitivity. In this paper, we present a method that avoids these restrictions, using a joint deep convolutional neural network-conditional random field (CNN-CRF) framework for monocular endoscopy depth estimation. Estimated depth is used to reconstruct the topography of the surface of the colon from a single image. We train the unary and pairwise potential functions of a CRF in a CNN on synthetic data, generated by developing an endoscope camera model and rendering over 200,000 images of an anatomically-realistic colon.We validate our approach with real endoscopy images from a porcine colon, transferred to a synthetic-like domain via adversarial training, with ground truth from registered computed tomography measurements. The CNN-CRF approach estimates depths with a relative error of 0.152 for synthetic endoscopy images and 0.242 for real endoscopy images. We show that the estimated depth maps can be used for reconstructing the topography of the mucosa from conventional colonoscopy images. This approach can easily be integrated into existing endoscopy systems and provides a foundation for improving computer-aided detection algorithms for detection, segmentation and classification of lesions.

Enhancing capacity among faith-based organizations to implement evidence-based cancer control programs: a community-engaged approach

Evidence-based interventions (EBIs) to promote cancer control among Latinos have proliferated in recent years, though adoption and implementation of these interventions by faith-based organizations (FBOs) is limited. Capacity building may be one strategy to promote implementation. In this qualitative study, 18 community key informants were interviewed to (a) understand existing capacity for health programming among Catholic parishes, (b) characterize parishes' resource gaps and capacity-building needs implementing cancer control EBIs, and (c) elucidate strategies for delivering capacity-building assistance to parishes to facilitate implementation of EBIs. Semi-structured qualitative interviews were conducted. Key informants concurred about the capacity of Catholic parishes to deliver health programs, and described attributes of parishes that make them strong partners in health promotion initiatives, including a mission to address physical and mental health, outreach to marginalized groups, altruism among members, and existing engagement in health programming. However, resource gaps and capacity building needs were also identified. Specific recommendations participants made about how existing resources might be leveraged to address challenges include to: establish parish wellness committees; provide "hands-on" learning opportunities for parishioners to gain program planning skills; offer continuous, tailored, on-site technical assistance; facilitate relationships between parishes and community resources; and provide financial support for parishes. Leveraging parishes' existing resources and addressing their implementation needs may improve adoption of cancer control EBIs.

Polyp detection rate may predict adenoma detection rate: a meta-analysis

BACKGROUND

Adenoma detection rate (ADR) is defined as the number of colonoscopies with at least one adenoma, expressed as the ratio of the total number of colonoscopies performed. Recently, an application of a conversion factor to estimate the ADR from the polyp detection rate (PDR) was described.

AIM

In this meta-analysis, we examined the correlation between ADR and PDR in the published studies and assessed the relative ratio of these ratios for a better and more accurate estimation.

METHODS

English Medical literature searches were performed for 'PDR' AND 'ADR'. A meta-analysis was carried out for papers that fulfilled the inclusion criteria using comprehensive meta-analysis software.

RESULTS

Twenty-five studies and 42 sets of data, including 31 623 patients, from nine countries published till 31 August 2017, were found. Funnel plot did not indicate a significant publication bias. relative ratio for ADR calculated from PDR was 0.688, 95% confidence intervals: 0.680-0.695, P value of less than 0.0001 in the meta-analysis fixed model. Heterogeneity (the proportion of inconsistency in individual studies) between studies was significant, with Q=492.753, d.f. (Q) 41, P<0.0001, and I 91.679.

CONCLUSION

We found the ratio of 0.688 can be used to calculate ADR from PDR for the individual endoscopist or for a group of endoscopists before receiving the formal results from the pathology department.

Threat Appeals: The Fear-Persuasion Relationship is Linear and Curvilinear

Drive theory may be seen as the first scientific theory of health and risk communication. However, its prediction of a curvilinear association between fear and persuasion is generally held to be incorrect. A close rereading of Hovland et al. reveals that within- and between-persons processes were conflated. Using a message that advocated obtaining a screening for colonoscopy, this study (N = 259) tested both forms of the inverted-U hypothesis. In the between-persons data, analyses revealed a linear effect that was consistent with earlier investigations. However, the data showed an inverted-U relationship in within-persons data. Hence, the relationship between fear and persuasion is linear or curvilinear depending on the level of analysis.

Can polyp detection rate be used prospectively as a marker of adenoma detection rate?

BACKGROUND

Adenoma detection rate (ADR) is a quality indicator for screening colonoscopy, but its calculation is time-consuming. Polyp detection rate (PDR) has been found to correlate with ADR; however, its use as a quality indicator has been criticized out of concern for endoscopists artificially inflating the PDR. We aim to evaluate whether active monitoring affects PDR.

METHODS

In March 2015, 14 endoscopists were made aware that their personal PDRs would be tracked monthly as a quality improvement project. Endoscopists received a report of their individual monthly and cumulative PDR, departmental averages, and a benchmark PDR. Following the intervention, data were collected for consecutive patients undergoing average risk screening colonoscopy for six months. PDR, ADR, and adenoma to polyp detection ratio quotient (APDRQ) were compared to a six-month pre-intervention period.

RESULTS

2203 patients were included in the study. There was no statistically significant difference in PDR when comparing pre- and post-intervention (44 vs. 45%, OR 1.04; 95% CI 0.77-1.36). No statistically significant difference in ADR was observed when comparing pre- and post-intervention (29 vs. 30%, OR 1.03; 95% CI 0.64-1.52). There was no statistically significant difference in APDRQ when comparing pre- and post-intervention (0.67 vs. 0.66, OR 0.99; 95% CI 0.69-1.33).

CONCLUSIONS

Monthly report cards did not result in a change in PDR or APDRQ. In some environments, PDR can be used as a surrogate marker of ADR, despite endoscopist awareness that PDR is being measured.

Association Between Colorectal Cancer Mortality and Gradient Fecal Hemoglobin Concentration in Colonoscopy Noncompliers

Background: To what extent the risk for colorectal cancer (CRC) death among noncompliers of colonoscopy is elevated following positive fecal immunological testing and whether the elevated risk varies with the fecal hemoglobin concentration (f-Hb) and location of CRC have not been researched.

Methods: We used data on 59 389 individuals (4.0%) among 1 489 937 Taiwanese screenees age 50 to 69 years with f-Hb 20 μg hemoglobin or more per gram of feces from 2004 to 2009. They were classified into 41 995 who received colonoscopy and 10 778 who received no confirmatory examination; the latter was categorized into three risk groups according to f-Hb (20–49, 50–99, and 100+). Mortality from CRC as the primary end point was monitored until December 31, 2012.

Results: A 1.64-fold (95% confidence interval [CI] = 1.32 to 2.04) increased risk for CRC death for the noncolonoscopy group as opposed to the colonoscopy group adjusting for differences in baseline characteristics. A gradient relationship was noted between cumulative mortality and age- and sex-adjusted f-Hb categories with 1.31-fold (95% CI = 1.04 to 1.71), 2.21-fold (95% CI = 1.55 to 3.34), and 2.53-fold (95% CI = 1.95 to 3.43) increased risk, respectively, for the 20–49, 50–99, and 100+ risk groups in the noncolonoscopy group compared with the colonoscopy group. The noncolonoscopy group led to a statistically significant 1.75-fold increased risk (95% CI = 1.35 to 2.33) for CRC of the distal colon but a statistically nonsignificant 1.11-fold increased risk (95% CI = 0.70 to 1.75) for the proximal colon, compared with the colonoscopy group. When the comparator was limited to subjects whose colonoscopy was completed to the cecum, the statistically significantly elevated risk for CRC mortality was seen for both distal and proximal colon in the noncolonoscopy group.

Conclusions: After a positive fecal immunochemical test, colonoscopy can reduce by about half the number of deaths from CRC. Among colonoscopy noncompliers, higher f-Hb is associated with an increased risk of mortality from CRC in a dose-response manner.

A CAD of fully automated colonic polyp detection for contrasted and non-contrasted CT scans

PURPOSE

Computer-aided detection (CAD) systems are developed to help radiologists detect colonic polyps over CT scans. It is possible to reduce the detection time and increase the detection accuracy rates by using CAD systems. In this paper, we aimed to develop a fully integrated CAD system for automated detection of polyps that yields a high polyp detection rate with a reasonable number of false positives.

METHODS

The proposed CAD system is a multistage implementation whose main components are: automatic colon segmentation, candidate detection, feature extraction and classification. The first element of the algorithm includes a discrete segmentation for both air and fluid regions. Colon-air regions were determined based on adaptive thresholding, and the volume/length measure was used to detect air regions. To extract the colon-fluid regions, a rule-based connectivity test was used to detect the regions belong to the colon. Potential polyp candidates were detected based on the 3D Laplacian of Gaussian filter. The geometrical features were used to reduce false-positive detections. A 2D projection image was generated to extract discriminative features as the inputs of an artificial neural network classifier.

RESULTS

Our CAD system performs at 100% sensitivity for polyps larger than 9 mm, 95.83% sensitivity for polyps 6-10 mm and 85.71% sensitivity for polyps smaller than 6 mm with 5.3 false positives per dataset. Also, clinically relevant polyps ([Formula: see text]6 mm) were identified with 96.67% sensitivity at 1.12 FP/dataset.

CONCLUSIONS

To the best of our knowledge, the novel polyp candidate detection system which determines polyp candidates with LoG filters is one of the main contributions. We also propose a new 2D projection image calculation scheme to determine the distinctive features. We believe that our CAD system is highly effective for assisting radiologist interpreting CT.

Modeling Individual Patient Preferences for Colorectal Cancer Screening Based on Their Tolerance for Complications Risk

INTRODUCTION

Recommendations for colorectal cancer screening encourage patients to choose among various screening methods based on individual preferences for benefits, risks, screening frequency, and discomfort. We devised a model to illustrate how individuals with varying tolerance for screening complications risk might decide on their preferred screening strategy.

METHODS

We developed a discrete-time Markov mathematical model that allowed hypothetical individuals to maximize expected lifetime utility by selecting screening method, start age, stop age, and frequency. Individuals could choose from stool-based testing every 1 to 3 years, flexible sigmoidoscopy every 1 to 20 years with annual stool-based testing, colonoscopy every 1 to 20 years, or no screening. We compared the life expectancy gained from the chosen strategy with the life expectancy available from a benchmark strategy of decennial colonoscopy.

RESULTS

For an individual at average risk of colorectal cancer who was risk neutral with respect to screening complications (and therefore was willing to undergo screening if it would actuarially increase life expectancy), the model predicted that he or she would choose colonoscopy every 10 years, from age 53 to 73 years, consistent with national guidelines. For a similar individual who was moderately averse to screening complications risk (and therefore required a greater increase in life expectancy to accept potential risks of colonoscopy), the model predicted that he or she would prefer flexible sigmoidoscopy every 12 years with annual stool-based testing, with 93% of the life expectancy benefit of decennial colonoscopy. For an individual with higher risk aversion, the model predicted that he or she would prefer 2 lifetime flexible sigmoidoscopies, 20 years apart, with 70% of the life expectancy benefit of decennial colonoscopy.

CONCLUSION

Mathematical models may formalize how individuals with different risk attitudes choose between various guideline-recommended colorectal cancer screening strategies.

Interpreting Perceived Effectiveness: Understanding and Addressing the Problem of Mean Validity

Research has shown that perceived message effectiveness (PE) correlates reasonably well with indices of actual effectiveness, but little attention has been given to how to interpret mean PE. This article describes the problem of mean validity and presents a research design that can be used to address it. Participants (N = 195) viewed messages that advocated being screened for colorectal cancer. The results showed downward bias in PE among members of the non-target audience (persons younger than 50) and upward bias as the referent for the judgment became more abstract/distant (self vs. persons older than 50 vs. general). The need for more research on mean validity is discussed. For applied researchers, recommendations for preferred indices of PE are offered.

Endoscopic Instruments and Electrosurgical Unit for Colonoscopic Polypectomy

Colorectal polypectomy is an effective method for prevention of colorectal cancer. Many endoscopic instruments have been used for colorectal polypectomy, such as snares, forceps, endoscopic clips, a Coagrasper, retrieval net, injector, and electrosurgery generator unit (ESU). Understanding the characteristics of endoscopic instruments and their proper use according to morphology and size of the colorectal polyp will enable endoscopists to perform effective polypectomy. I reviewed the characteristics of endoscopic instruments for colorectal polypectomy and their appropriate use, as well as the basic principles and settings of the ESU.

What are the Endoscopic and Pathological Characteristics of Colorectal Polyps?

BACKGROUND

Colon polyps need to be excised upon detection during colonoscopy due to the risk of malignancy irrespective of their size. In our study, we retrospectively evaluated the clinicopathological characteristics of polyps detected during colonoscopy.

MATERIALS AND METHODS

We assessed 379 patients with polyps detected during colonoscopy between January 2010 and May 2012. The demographics, complaints, colonoscopy findings (shape, place and size of the polyp) and histopathological findings were recorded. We carried out statistical analysis using PASW 18.0 for Windows.

RESULTS

There were 227 males (59.9%) and 152 females (40.1%) in the trial. The mean age was 53.8 years (32-90). The most common complaint was rectal bleeding (36.1%), followed by abdominal pain (35.4%). Polyps were detected most commonly in the rectosigmoid region (43.8%), followed by the descending colon (17.4%). Some 239 patients had a single polyp (63.1%) while 140 were found to have multiple polyps (36.9%). While tubular adenoma was the most common pathological type, occurring in 181 patients (47.8%), tubulovillous adenoma (14.2%) and hyperplastic polyp (12.7%) followed, occurring in 54 and 48 patients respectively. While 313 patients (82.6%) did not feature dysplasia, 37 patients (9.7%) exhibited low- grade dysplasia, 28 (7.7%) had high-grade dysplasia and 4 had cancer (1.1%). The rates of villous components and dysplasia were detected to be high among pedunculated polyps and polyps larger than 1 cm (p<0.001).

CONCLUSIONS

Due to the fact that large-diameter polyps with malignant potential are commonly located in the left colon and have a high prevalence among the middle-aged individuals, it would be appropriate to screen this population at regular intervals via rectosigmoidoscopy.

Influence of perception of colorectal cancer risk and patient bowel preparation behaviors: a study in minority populations

BACKGROUND

Large disparities exist in the utilization rates of screening modalities for colorectal cancer (CRC) in different socioeconomic areas. In this study, we evaluated whether the quality of bowel preparation differed significantly among populations with a high risk of CRC compared with that among the general population after matching for potential confounding factors.

METHODS

Hispanic and African American patients who underwent routine screening or surveillance colonoscopies in an outpatient setting between 2003 and 2013 were included in this retrospective study. Patients who underwent colonoscopies for emergent indications and repeat routine screening colonoscopies because of prior history of inadequate bowel preparation were excluded from this study. The patients were divided into three groups: patients having an average risk of being diagnosed with CRC (group 1); patients having a high risk of being diagnosed with CRC because of a personal history of adenomatous polyps (group 2); and patients having a high risk of being diagnosed with CRC because of a family history of CRC in first-degree relatives (group 3). All the patients were given preprocedural counseling and written instructions for bowel preparation. Data on demographic information, method of bowel preparation, quality of bowel preparation, comorbidities, and prescription medications were collected.

RESULTS

In all, 834 patients had a "high-risk for CRC" surveillance colonoscopy in view of their personal history of adenomatous polyps and were included in group 2. In total, 250 patients had a "high-risk for CRC" screening colonoscopy in view of their family history of CRC in first-degree relatives and were included in group 3. Further, 1,000 patients were selected to serve as controls (after matching for age, sex and ethnicity) and were included in group 1. Bowel preparation was graded as good, fair, or poor by the endoscopist performing the study. We observed a significantly higher number of good bowel preparations in group 2 and group 3 (P=0.0001) when compared with group 1 (controls) after adjusting for comorbidities and usage of prescription medication that could potentially cause colonic dysmotility. These differences were significant in both Hispanic and African American patients.

CONCLUSION

Our study showed that perception of CRC risk significantly influenced the bowel preparation behaviors of patients belonging to minority populations, with a significantly greater number of patients with a high risk of CRC having adequate bowel preparations.

Polypectomy practices of sub-centimeter polyps in the English Bowel Cancer Screening Programme

BACKGROUND

Most colonic polyps are small, and several polypectomy techniques are available. We aimed to describe the variation in polypectomy techniques employed for the removal of sub-centimeter polyps in relation to polyp characteristics, completeness of histological excision and safety.

METHODS

Prospectively collected data relating to the removal of sub-centimeter polyps over a 3-year period (between January 2010 and December 2012) were retrieved from the English Bowel Cancer Screening Programme.

RESULTS

A total of 147,174 sub-centimeter polyps were removed during 62,679 procedures. For pedunculated polyps, hot snare was most common in the left (median 92 %, IQR 83.3-97.0 %) and right colon (median 75 %, IQR 3-92 %). For non-pedunculated polyps, cold snare was most common in the right colon (median 24 %, IQR 9-47 %); whereas hot snare remained most common in the left colon (median 32 %, IQR 19-49 %). Surgeons were more likely than physicians to use diathermy-assisted techniques (65.6 vs. 56.5 %, p < 0.001). Twelve (0.03 %) bleeding episodes required transfusion with no polypectomy technique dominating and 16 (0.04 %) perforations with 81 % of polypectomies performed using diathermy-assisted techniques. There was substantial variation between screening centers for the completeness of histological excision. For non-pedunculated polyps, histologically confirmed complete excision was more after EMR (23.4 %) compared with other techniques (cold biopsy forceps 17.7 %, cold snare 15.1 %, hot biopsy forceps 19.1 %, hot snare 21.5 %). The use of cold techniques and EMR has increased over time, whereas the use of hot biopsy forceps and hot snare has decreased (p < 0.001).

CONCLUSIONS

The removal of sub-centimeter polyps within the BCSP is safe despite wide variations in practice. The use of cold resection techniques and EMR has increased over time. The histological assessment for completeness of excision is limited and should be confirmed endoscopically at the time of polypectomy.

Discovery and validation of new potential biomarkers for early detection of colon cancer

BACKGROUND

Accurate detection of characteristic proteins secreted by colon cancer tumor cells in biological fluids could serve as a biomarker for the disease. The aim of the present study was to identify and validate new serum biomarkers and demonstrate their potential usefulness for early diagnosis of colon cancer.

METHODS

The study was organized in three sequential phases: 1) biomarker discovery, 2) technical and biological validation, and 3) proof of concept to test the potential clinical use of selected biomarkers. A prioritized subset of the differentially-expressed genes between tissue types (50 colon mucosa from cancer-free individuals and 100 normal-tumor pairs from colon cancer patients) was validated and further tested in a series of serum samples from 80 colon cancer cases, 23 patients with adenoma and 77 cancer-free controls.

RESULTS

In the discovery phase, 505 unique candidate biomarkers were identified, with highly significant results and high capacity to discriminate between the different tissue types. After a subsequent prioritization, all tested genes (N = 23) were successfully validated in tissue, and one of them, COL10A1, showed relevant differences in serum protein levels between controls, patients with adenoma (p = 0.0083) and colon cancer cases (p = 3.2e-6).

CONCLUSION

We present a sequential process for the identification and further validation of biomarkers for early detection of colon cancer that identifies COL10A1 protein levels in serum as a potential diagnostic candidate to detect both adenoma lesions and tumor.

IMPACT

The use of a cheap serum test for colon cancer screening should improve its participation rates and contribute to decrease the burden of this disease.

A population-based cross-sectional study of colorectal cancer screening practices of first-degree relatives of colorectal cancer patients

Background

The aim of this study was to determine the proportions and predictors of first-degree relatives (FDRs) of colorectal cancer (CRC) patients (i) ever receiving any CRC testing and (ii) receiving CRC screening in accordance with CRC screening guidelines.

Methods

Colorectal cancer patients and their FDRs were recruited through the population-based Victorian Cancer Registry, Victoria, Australia. Seven hundred and seven FDRs completed telephone interviews. Of these, 405 FDRs were deemed asymptomatic and eligible for analysis.

Results

Sixty-nine percent of FDRs had ever received any CRC testing. First-degree relatives of older age, those with private health insurance, siblings and FDRs who had ever been asked about family history of CRC by a doctor were significantly more likely than their counterparts to have ever received CRC testing. Twenty-five percent of FDRs “at or slightly above average risk” were adherent to CRC screening guidelines. For this group, adherence to guideline-recommended screening was significantly more likely to occur for male FDRs and those with a higher level of education. For persons at “moderately increased risk” and “potentially high risk”, 47% and 49% respectively adhered to CRC screening guidelines. For this group, guideline-recommended screening was significantly more likely to occur for FDRs who were living in metropolitan areas, siblings, those married or partnered and those ever asked about family history of CRC.

Conclusions

A significant level of non-compliance with screening guidelines was evident among FDRs. Improved CRC screening in accordance with guidelines and effective systematic interventions to increase screening rates among population groups experiencing inequality are needed.

Trial Registration

Australian and New Zealand Clinical Trial Registry: ACTRN12609000628246

Shorter peripheral blood telomeres are a potential biomarker for patients with advanced colorectal adenomas

BACKGROUND

Colorectal cancer (CRC) can be prevented by the early detection and removal of advanced adenomas (AAs) by colonoscopy. Our aim was to evaluate peripheral blood leukocyte (PBL) telomere length as a potential biomarker for the presence of AAs.

METHODS

PBL telomere length was measured in patients with AAs (n=35), in a control group of similarly aged patients who had a normal colonoscopy (n=145) and in a separate population group with no history of cancer, again similarly aged (n=495). Telomere measurements were performed using a quantitative PCR assay and reported as ratios of telomere and single copy gene measurements.

RESULTS

Telomere lengths tended to be lower in patients with AAs than in patients in the normal colonoscopy group (p<0.001) as well as those in the population group (p=0.011). A telomere/single copy gene ratio of 0.5 was found to have an estimated 94% sensitivity and a 56% specificity for AAs; a combination of sensitivity and specificity for which a value of >0.5 would reduce the odds of a patient having AAs by a factor of 0.11 (the negative likelihood ratio). Thirty three percent of individuals in the population group tested above this cutoff and could be considered at low risk for AAs.

CONCLUSIONS

PBL telomeres are shortened in patients with colorectal neoplasia, suggesting that PBL telomere length could be a promising non-invasive blood biomarker to pre-screen for risk of AAs prior to colonoscopy.

Clinical end points for developing pharmaceuticals to manage patients with a sporadic or genetic risk of colorectal cancer

To reduce the morbidity and mortality from colorectal cancer (CRC), current clinical practice focuses on screening for early detection and polypectomy as a form of secondary prevention, complemented with surgical interventions when appropriate. No pharmaceutical agent is currently approved for use in clinical practice for the management of patients at risk for CRC. This article will review earlier attempts to develop pharmaceuticals for use in managing patients with a sporadic or genetic risk of CRC. It will also discuss therapeutic end points under evaluation in current efforts to develop drugs for treating CRC risk factors.

Is production pressure jeopardizing the quality of colonoscopy? A survey of U.S. endoscopists' practices and perceptions

BACKGROUND

Fatigue is an underestimated cause of underperformance among physicians. There is evidence that fatigue or other byproducts of production pressure may negatively influence the quality of colonoscopy.

OBJECTIVE

To investigate the practices and perceptions of U.S. endoscopists regarding the effect of production pressure on the performance of colonoscopy.

DESIGN

We conducted a 40-question online survey to assess endoscopists' practices and perceptions concerning production pressure.

SETTING

A total of 5030 U.S. American Society for Gastrointestinal Endoscopy members.

MAIN OUTCOME MEASUREMENTS

The proportion of endoscopists responding positively to questions pertaining to the impact of production pressure on colonoscopy practice.

RESULTS

Ninety-two percent of respondents indicated that production pressure influenced one or more aspects of their endoscopic practices. Examples of production pressure included (1) postponing polypectomy for a subsequent session (2.8%), (2) reducing the length of time spent inspecting the colon (7.2%), and (3) proceeding with colonoscopy in a patient with an unfavorable risk/benefit ratio (69.2%). Forty-eight percent of respondents reported witnessing the effects of production pressure on a colleague. Respondents working fee-for-service and those with >10 years since completion of fellowship were more likely to describe their weekly workloads as excessive compared with those who were salaried (81.3% vs 71.3%; P = .01) and <10 years out of training (81% vs 72.7%; P = .01).

LIMITATIONS

Nonresponse bias due to low response rate (22.3%).

CONCLUSION

Production pressure influences the conduct of colonoscopy for many endoscopists and could have an adverse effect on the outcome of colorectal cancer screening. (

CLINICAL TRIAL REGISTRATION NUMBER

RE:GIE D 11-01288R1.) The study was an Internet study and did not involve human subjects.

Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths

BACKGROUND

In the National Polyp Study (NPS), colorectal cancer was prevented by colonoscopic removal of adenomatous polyps. We evaluated the long-term effect of colonoscopic polypectomy in a study on mortality from colorectal cancer.

METHODS

We included in this analysis all patients prospectively referred for initial colonoscopy (between 1980 and 1990) at NPS clinical centers who had polyps (adenomas and nonadenomas). The National Death Index was used to identify deaths and to determine the cause of death; follow-up time was as long as 23 years. Mortality from colorectal cancer among patients with adenomas removed was compared with the expected incidence-based mortality from colorectal cancer in the general population, as estimated from the Surveillance Epidemiology and End Results (SEER) Program, and with the observed mortality from colorectal cancer among patients with nonadenomatous polyps (internal control group).

RESULTS

Among 2602 patients who had adenomas removed during participation in the study, after a median of 15.8 years, 1246 patients had died from any cause and 12 had died from colorectal cancer. Given an estimated 25.4 expected deaths from colorectal cancer in the general population, the standardized incidence-based mortality ratio was 0.47 (95% confidence interval [CI], 0.26 to 0.80) with colonoscopic polypectomy, suggesting a 53% reduction in mortality. Mortality from colorectal cancer was similar among patients with adenomas and those with nonadenomatous polyps during the first 10 years after polypectomy (relative risk, 1.2; 95% CI, 0.1 to 10.6).

CONCLUSIONS

These findings support the hypothesis that colonoscopic removal of adenomatous polyps prevents death from colorectal cancer. (Funded by the National Cancer Institute and others.).

Relationship of colorectal cancer awareness and knowledge with colorectal cancer screening

AIM

The aim was to describe the association of awareness and knowledge with participation in colorectal cancer (CRC) screening.

MATERIALS & METHODS

Telephone survey research was conducted with South Carolina (USA) residents aged 50-75 years using a 144-item instrument. Data were analyzed with SAS and Stata. Adjusted odds ratios are reported.

RESULTS

Respondents (n = 1302) had heard of CRC screening (96%) and exhibited high levels of CRC awareness and knowledge; only 74% had ever been screened. Higher levels of knowledge were associated with a greater likelihood of having ever been screened (odds ratio: 1.05; 95% CI: 1.02-1.41; p < 0.001).

CONCLUSION

Results showed high levels of awareness and knowledge, but modest participation in CRC. Transforming awareness and knowledge into CRC screening participation should be a priority.

Assessing the impact of screening colonoscopy on mortality in the medicare population

BACKGROUND

Some have recommended against routine screening for colorectal cancer (CRC) among patients ≥75 years of age, while others have suggested that screening colonoscopy (SC) is less beneficial for women than men. We estimated the expected benefits (decreased mortality from CRC) and harms (SC-related mortality) of SC based on sex, age, and comorbidity.

OBJECTIVE

To stratify older patients according to expected benefits and harms of SC based on sex, age, and comorbidity.

DESIGN

Retrospective study using Medicare claims data.

PARTICIPANTS

Medicare beneficiaries 67-94 years old with and without CRC.

MAIN MEASURES

Life expectancy, CRC- and colonoscopy-attributable mortality rates across strata of sex, age, and comorbidity, pay-off time (i.e. the minimum time until benefits from SC exceeded harms), and life-years saved for every 100,000 SC.

KEY RESULTS

Increasing age and comorbidity were associated with lower CRC-attributable mortality. Due to shorter life expectancy and CRC-attributable mortality, the benefits associated with SC were substantially lower among patients with greater comorbidity. Among men aged 75-79 years with no comorbidity, the number of life-years saved was 459 per 100,000 SC, while men aged 67-69 with ≥3 comorbidities had 81 life-years saved per 100,000 SC. There was no evidence that SC was less effective in women. Among men and women 75-79 with no comorbidity, number of life-years saved was 459 and 509 per 100,000 SC, respectively; among patients with ≥3 comorbidities, there was no benefit for either men or women.

CONCLUSIONS

Although the effectiveness of SC was equivalent for men and women, there was substantial variation in SC effectiveness within age groups, arguing against screening recommendations based solely on age.

Screening for colorectal cancer: possible improvements by risk assessment evaluation?

Emerging results indicate that screening improves survival of patients with colorectal cancer. Therefore, screening programs are already implemented or are being considered for implementation in Asia, Europe and North America. At present, a great variety of screening methods are available including colono- and sigmoidoscopy, CT- and MR-colonography, capsule endoscopy, DNA and occult blood in feces, and so on. The pros and cons of the various tests, including economic issues, are debated. Although a plethora of evaluated and validated tests even with high specificities and reasonable sensitivities are available, an international consensus on screening procedures is still not established. The rather limited compliance in present screening procedures is a significant drawback. Furthermore, some of the procedures are costly and, therefore, selection methods for these procedures are needed. Current research into improvements of screening for colorectal cancer includes blood-based biological markers, such as proteins, DNA and RNA in combination with various demographically and clinically parameters into a "risk assessment evaluation" (RAE) test. It is assumed that such a test may lead to higher acceptance among the screening populations, and thereby improve the compliances. Furthermore, the involvement of the media, including social media, may add even more individuals to the screening programs. Implementation of validated RAE and progressively improved screening methods may reform the cost/benefit of screening procedures for colorectal cancer. Therefore, results of present research, validating RAE tests, are awaited with interest.

Screening for colorectal cancer: established and emerging modalities

It has been estimated that >95% of cases of colorectal cancer (CRC) would benefit from curative surgery if diagnosis was made at an early or premalignant polyp stage of disease. Over the past 10 years, most developed nation states have implemented mass population screening programs, which are typically targeted at the older (at-risk) age group (>50-60 years old). Conventional screening largely relies on periodic patient-centric investigation, particularly involving colonoscopy and flexible sigmoidoscopy, or else on the fecal occult blood test. These methods are compromised by either low cost-effectiveness or limited diagnostic accuracy. Advances in the development of diagnostic molecular markers for CRC have yielded an expanding list of potential new screening modalities based on investigations of patient stool (for colonocyte DNA mutations, epigenetic changes or microRNA expression) or blood specimens (for plasma DNA mutations, epigenetic changes, heteroplasmic mitochondrial DNA mutations, leukocyte transcriptome profile, plasma microRNA expression or protein and autoantibody expression). In this Review, we present a critical evaluation of the performance data and relative merits of these various new potential methods. None of these molecular diagnostic methods have yet been evaluated beyond the proof-of-principle and pilot-scale study stage and it could be some years before they replace existing methods for population screening in CRC.

Recommendations for post-polypectomy surveillance in community practice

BACKGROUND

After colon cancer screening, large numbers of persons discovered with colon polyps may receive post-polypectomy surveillance with multiple colonoscopy examinations over time. Decisions about surveillance interval are based in part on polyp size, histology, and number.

AIMS

To learn physicians' recommendations for post-polypectomy surveillance from physicians' office charts.

METHODS

Among 322 physicians performing colonoscopy in 126 practices in N. Carolina, offices of 152 physicians in 55 practices were visited to extract chart data, for each physician, on 125 consecutive persons having colonoscopy in 2003. Subjects included persons with first-time colonoscopy and no positive family history or other indication beyond colonoscopy findings that might affect post-polypectomy surveillance recommendations. Data were extracted about demographics, reason for colonoscopy, family history, symptoms, bowel prep, extent of examination, and features of each polyp including location, size, histology. Recommendations for post-polypectomy surveillance were noted.

RESULTS

Among 10,089 first-time colonoscopy examinations, hyperplastic polyps were found in 4.5% of subjects, in whom follow-up by 4-6 years was recommended in 24%, sooner than recommended in guidelines. Of the 6.6% of persons with only small adenomas, 35% were recommended to return in 1-3 years (sooner than recommended in some guidelines) and 77% by 6 years. Surveillance interval tended to be shorter if colon prep was less than "excellent." Prep quality was not reported for 32% of examinations.

CONCLUSIONS

Surveillance intervals after polypectomy of low-risk polyps may be more aggressive than guidelines recommend. The quality of post-polypectomy surveillance might be improved by increased attention to guidelines, bowel prep, and reporting.

A public-health perspective on screening colonoscopy

Colorectal cancer is an important global health problem. Randomized trials have shown that screening programs can reduce both colorectal cancer incidence and mortality, and guidelines strongly support screening. Nevertheless, screening rates are relatively low and concerted efforts are being made to increase screening uptake. Many guidelines and practitioners have come to view colonoscopy as the optimal screening strategy. Colonoscopy provides both a gold-standard diagnostic test and, with polypectomy, a therapeutic intervention that can prevent cancer. However, from a public-health perspective, emphasizing colonoscopy is problematic. The efficacy of colonoscopy has not been supported with randomized trial data, accuracy is imperfect, procedural quality is variable, complications are not uncommon, endoscopic capacity is limited, procedure costs are high, and many patients prefer alternative tests. Successful screening programs will need to provide a range of screening modalities and ensure that endoscopic resources are used efficiently.

State of the Art Review: Colorectal Cancer Screening

Although colorectal cancer is the third leading cause of cancer-related deaths in the U.S., the burden of this disease could be dramatically reduced by increased utilization of screening. Evidence-based recommendations and guidelines from national societies recommend screening all average risk adults starting at age fifty. However, the myriad of screening options and slight differences in screening recommendations between guidelines may lead to confusion among patients and their primary care providers. This goal of this review is to briefly summarize the colorectal cancer screening guidelines issued by three major organizations, compare their recommendations, and address emerging issues in colorectal cancer screening.

Sensitivity of immunochemical faecal occult blood testing for detecting left- vs right-sided colorectal neoplasia

Background:

Faecal occult blood tests (FOBTs) are used for colorectal cancer (CRC) screening. We aimed to assess the sensitivity of an immunochemical FOBT for detecting advanced colorectal neoplasia in the left vs the right colon and to explore reasons for potential differences in site-specific test performance.

Methods:

We prospectively measured faecal occult blood levels by a quantitative immunochemical FOBT (RIDASCREEN) in 2310 average-risk subjects undergoing screening colonoscopy. We compared diagnostic performance for subjects with left- vs right-sided advanced neoplasia, as well as patient characteristics and adenoma characteristics that have been suggested to impact faecal haemoglobin levels.

Results:

Sensitivities for subjects with left- vs right-sided advanced neoplasia were 33% (95% confidence interval (CI), 26–41%) and 20% (CI, 11–31%) (P=0.04) at a specificity of 95% (overall sensitivity: 29%) and the areas under the receiver-operating characteristics curve were 0.71 (CI, 0.69–0.72) and 0.60 (CI, 0.58–0.63), respectively. Pedunculated shape was strikingly more common in participants with left- vs right-sided advanced neoplasia (47% vs 14%). In logistic regression analyses adjusted for site, pedunculated shape was statistically significantly associated with test sensitivity (P=0.04).

Conclusions:

The immunochemical FOBT in our study was more sensitive for detecting subjects with left- vs right-sided advanced colorectal neoplasia. Our findings may stimulate further diagnostic research in the field as well as modelling analyses to estimate the potential effect of site-specific test performance on the effectiveness of annual or biennial FOBT-based screening programmes, in particular with respect to protection from right-sided CRC.

Risk of second primary colorectal cancer among colorectal cancer cases: a population-based analysis

BACKGROUND

Patients with history of colorectal cancer (CRC) are at increased risk for developing a second primary colorectal cancer (SPCRC) as compared to the general population. However, the degree of risk is uncertain. Here, we attempt to quantify the risk, using data from the large population-based California Cancer Registry (CCR).

MATERIALS AND METHODS

We analyzed the CCR data for cases with surgically-treated colon and rectal cancer diagnosed during the period 1990-2005 and followed through up to January 2008. We excluded those patients diagnosed with metastatic disease and those in whom SPCRC was diagnosed within 6 months of the diagnosis of the primary CRC. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated to evaluate risk as compared to the underlying population after taking into account age, sex, ethnicity, and time at risk.

RESULTS

The study cohort consisted of 69809 cases with colon cancer and 34448 with rectal cancer. Among these patients there were 1443 cases of SPCRCs. The SIR for developing SPCRC was higher in colon cancer survivors (SIR=1.4; 95% CI: 1.3 to 1.5) as compared to the underlying population. The incidence of SPCRC was also higher in females (SIR=1.5; 95% CI: 1.3 to 1.6) and Hispanics (SIR=2.0; 95% CI: 1.7 to 2.4) with primary colon cancer. The SIR for developing an SPCRC was higher only among those whose initial tumor was located in the descending colon (SIR=1.6; 95% CI: 1.3 to 2.0) and proximal colon (SIR=1.4; 95% CI: 1.3 to 1.6).

CONCLUSIONS

Our results confirm that CRC patients, especially females and Hispanics, are at a higher risk of developing SPCRC than the general population. Differential SPCRC risk by colorectal tumor subsite is dependent on gender and ethnicity, underscoring the heterogeneous nature of CRC.

Colorectal cancer mortality prevented by use and attributable to nonuse of colonoscopy

BACKGROUND

Use of colonoscopy is thought to reduce colorectal cancer (CRC) mortality, but its impact at the population level is unclear.

OBJECTIVE

To estimate the effect of current colonoscopy use on CRC mortality and its further potential in reducing CRC mortality.

DESIGN

Population-level analysis was performed by using the concepts of prevented and attributable fractions, by using data from the National Health Interview Survey, the Surveillance, Epidemiology and End Results Program, and estimates of the effectiveness of colonoscopy at reducing CRC mortality.

SETTING

The 2005 U.S. population aged 50 years and older.

EXPOSURE

Colonoscopy within 10 years or less.

MAIN OUTCOME MEASUREMENTS

Percentages and absolute numbers of CRC deaths prevented and potentially preventable by colonoscopy.

LIMITATIONS

Uncertainty in effectiveness estimates.

RESULTS

Overall, the proportions of CRC deaths in 2005 prevented by colonoscopy (ie, the prevented fractions) range from 13% (95% CI, 11%-15%) to 19% (95% CI, 12%-24%) across the estimates of colonoscopy effectiveness. Corresponding numbers of CRC deaths prevented range from 7314 (95% CI, 6010-8467) to 11,711 (95% CI, 7077-14,898). The proportions of CRC deaths attributable to nonuse of colonoscopy (ie, the attributable fractions) range from 28% (95% CI, 22%-33%) to 44% (95% CI, 24%-60%), depending on the assumed effectiveness. Corresponding numbers of CRC deaths attributed to nonuse of colonoscopy range from 13,796 (95% CI, 11,076-16,255) to 22,088 (95% CI, 12,189-29,947).

CONCLUSIONS

Although we estimate that colonoscopy has prevented substantial numbers of CRC deaths, many more deaths could have been prevented with more widespread use. These findings highlight the potential benefits from public health interventions to increase the use of screening colonoscopy.

Application of a conversion factor to estimate the adenoma detection rate from the polyp detection rate

BACKGROUND

The adenoma detection rate (ADR) is a quality benchmark for colonoscopy. Many practices find it difficult to determine the ADR because it requires a combination of endoscopic and histologic findings. It may be possible to apply a conversion factor to estimate the ADR from the polyp detection rate (PDR).

OBJECTIVE

To create a conversion factor that can be used to accurately estimate the ADR from the PDR.

DESIGN

This was a retrospective study of colonoscopies performed by board-certified gastroenterologists to determine the average adenoma to polyp detection rate quotient (APDRQ) for all endoscopists, individually and as a group.

SETTING

Academic group practice.

INTERVENTION

The group average APDRQ was used as a conversion factor for the endoscopist's PDR to estimate the ADR.

MAIN OUTCOME MEASUREMENTS

The strength of the relationship between the estimated ADR and the actual ADR determined by Pearson's correlation coefficient.

RESULTS

A total of 3367 colonoscopies performed by 20 staff gastroenterologists were included. The average ADR for all indications, all patient age groups, and both sexes was 0.17 (range 0.09-0.27, standard deviation 0.05). The average APDRQ was 0.64 (range 0.46-1.00, standard deviation 0.13). The correlation between the estimated ADR and the actual ADR was 0.85 (95% CI, 0.65-0.93, P = .000001).

LIMITATIONS

Retrospective study in 1 practice setting with all patient types.

CONCLUSIONS

The use of a conversion factor can accurately estimate the ADR from the PDR. Further study is needed to determine whether such a conversion factor can be applied to different practice settings and patient groups.

The reduction in colorectal cancer mortality after colonoscopy varies by site of the cancer

BACKGROUND & AIMS

There are limited data on mortality from colorectal cancer (CRC) among patients who have received colonoscopy examinations. We sought to determine CRC mortality among persons undergoing colonoscopies compared with the general population.

METHODS

We identified all individuals who had a colonoscopy as their first lower gastrointestinal endoscopy from April 1, 1987, to September 30, 2007 (24,342 men and 30,461 women), based on information from Manitoba's provincial physicians' billing claims database. Patients were followed until March 31, 2008, death, or migration out of the province (310,718 person-years). Individuals less than 50 years of age or more than 80 years of age at the index colonoscopy or those with prior sigmoidoscopy, inflammatory bowel disease, resective colorectal surgery, or CRC were excluded. CRC mortality after the index colonoscopy was compared with that of the general population by standardized mortality ratios (SMRs). Stratified analyses were performed to determine CRC mortality for different age groups at index colonoscopy and sex, duration of follow-up, medical specialty of the endoscopist, and site of CRC.

RESULTS

There was a 29% reduction in overall CRC mortality (SMR, 0.71; 95% confidence interval [CI], 0.61-0.82], a 47% reduction in mortality from distal CRC (SMR, 0.53; 95% CI, 0.42-0.67), and no reduction in mortality from proximal CRC (SMR, 0.94; 95% CI, 0.77-1.17). The reduction in mortality from distal CRC remained significant for follow-up beyond 10 years (SMR, 0.53; 95% CI, 0.31-0.84).

CONCLUSIONS

In Manitoba, colonoscopies significantly reduce mortality from CRC, but the benefit is not uniform for colorectal tumors that arise in different areas of the colon.

Quality and safety of screening colonoscopies performed by primary care physicians with standby specialist support

BACKGROUND

Expanding the population's access to colonoscopy screening can reduce colorectal cancer disparities. Innovative strategies are needed to address the prevailing 50% colonoscopy screening gap, partly attributable to inadequate specialist workforce. This study examined the quality of colonoscopies by primary care physicians (PCPs) with standby specialist support at a licensed ambulatory surgery center.

METHODS

Retrospective data on 10,958 consecutive colonoscopies performed by 51 PCPs on 9815 patients from October 2002 to November 2007 were used to calculate the rates of cecal intubation, detection of polyps, adenomas, advanced neoplasia and cancer, adverse events, and time taken for endoscope insertion and withdrawal. The center's protocol requires a 2-person technique (using a trained technician), polyp search and removal during both scope insertion and withdrawal, and onsite expert always available for rescue assistance (either navigational or therapeutic).

FINDINGS

Mean patient age was 58.3 (+/-10.9) years, 48.0% were male, and 48.1% African-American. The cecal intubation rate was 98.1%, polyp detection rate 63.1%, hyperplastic polyp 27.5%, adenoma 29.9%, advanced neoplasia 5.7%, cancer 0.63%, major adverse events 0.06% (including 2 perforations; no death). Mean insertion and withdrawal times were 14.4 (+/-9.3) and 10.9 (+/-6.8) minutes, respectively; 13.2 (+/-8.6) and 8.0 (+/-4.5) minutes without polyps found, and 15.1 (+/-9.6) and 12.5 (+/-7.3) minutes when > or =1 polyp was found.

CONCLUSIONS

In the largest published study of PCP-performed colonoscopies with standby specialist support, we observed performance quality indicators and lesion detection rates that are comparable to documented rates for experienced gastroenterologists. Systems that use PCPs with specialist backup support enable high-quality colonoscopy performance by PCPs.

Colorectal cancer incidence trends in the United States and United kingdom: evidence of right- to left-sided biological gradients with implications for screening

Several lines of evidence support the premise that screening colonoscopy reduces colorectal cancer (CRC) incidence, but there may be differential benefits for right- and left-sided tumors. To better understand the biological basis of this differential effect, we derived biomathematical models of CRC incidence trends in U.S. and U.K. populations, representing relatively high- and low-prevalence screening, respectively. Using the Surveillance Epidemiology and End Results (SEER) and the Office for National Statistics (ONS) registries (both 1973-2006), we derived stochastic multistage clonal expansion (MSCE) models for right-sided (proximal colon) and left-sided (distal colon and rectal) tumors. The MSCE concept is based on the initiation-promotion-progression paradigm of carcinogenesis and provides a quantitative description of natural tumor development from the initiation of an adenoma (via biallelic tumor suppressor gene inactivation) to the clinical detection of CRC. From 1,228,036 (SEER: 340,582; ONS: 887,454) cases, parameter estimates for models adjusted for calendar-year and birth-cohort effects showed that adenoma initiation rates were higher for right-sided tumors, whereas, paradoxically, adenoma growth rates were higher for left-sided tumors. The net effect was a higher cancer risk in the right colon only after age 70 years. Consistent with this finding, simulations of adenoma development predicted that the relative prevalence for right- versus left-sided tumors increases with increasing age, a differential effect most striking in women. Using a realistic biomathematical description of CRC development for two nationally representative registries, we show age- and sex-dependent biological gradients for right- and left-sided colorectal tumors. These findings argue for an age-, sex-, and site-directed approach to CRC screening.

Physician barriers to population-based, fecal occult blood test-based colorectal cancer screening programs for average-risk patients

BACKGROUND

Colorectal cancer (CRC) screening is an efficacious but underused means to reduce the burden of CRC. Population-based CRC screening programs are currently being implemented in Canada and physicians are key partners in increasing screening uptake. The current study identified physician attitudes and barriers that need to be addressed by provincial programs.

METHODS

A mailed survey of primary care physicians in Alberta.

RESULTS

The survey response rate was 42.4% (806 of 1903). The majority of physicians suggested CRC screening as part of a routine periodic examination; however, the approach to test selection and the type of tests recommended varied by geographical region. The majority of physicians agreed (48%) or strongly agreed (36%) that a provincewide screening program is the best approach to reducing mortality from CRC. However, there were many serious concerns identified - the most common was endoscopic capacity for follow-up of patients with a positive fecal occult blood test (FOBT), which was cited by 55% to 69% of the physicians surveyed. The barriers to three commonly available tests (FOBT, flexible sigmoidoscopy and colonoscopy) varied according to health region, and the types of barriers identified varied according to the specific test.

INTERPRETATION

Screening for CRC is gradually being accepted among primary care physicians in Alberta. A key finding of the present descriptive study was the regional variation in practices, perceived barriers and concerns about provincial population-based screening programs based on FOBT as the primary screening test. Provincial programs will need to address the issue of endoscopic capacity and perceived barriers to FOBT to gain primary care physician acceptance of FOBT-based CRC screening programs.

Colorectal cancer screening in evolution: Japan and the USA

Colorectal cancer (CRC) is one of the most common cancers in both Japan and the USA. Age-adjusted incidence of CRC has been in decline in the USA since 1985, while rates in Japan have been increasing. The decline in the USA is commonly attributed to CRC screening programs but there is little direct evidence to support this assertion. The current screening recommendations in the USA cover several options including colonoscopy and computerized tomographic colonography (CTC). The Japanese CRC screening program is centered on fecal immunochemistry testing (FIT). The US government Medicare program's approval of colonoscopy as a primary screening test has lead to a large increase in the number of patients undergoing the procedure. However, the benefit achieved from this change in screening program emphasis is not clear. Simulation models demonstrate that a screening program centered on FIT achieves 94% of the benefit that an all-colonoscopy program is able to accomplish but at a lower cost per life year gained. Clinical studies of colonoscopy have failed to demonstrate the 76-90% declines in CRC incidence predicted by the National Polyp Study published in 1993. A potential reason for this failure is the quality of colonoscopy performance. Until more compelling data becomes available demonstrating the utility of colonoscopy as a primary screening modality, there is little incentive to alter the proven cost-effective approach to CRC screening currently in practice in Japan.