Mass Screening For Colorectal Cancer Research Articles

Review of the Thorough-check-up Rate in the Prefectural Mass Screening for Colorectal Cancer in Kochi Prefecture

Review of the Thorough-check-up Rate in the Prefectural Mass Screening for Colorectal Cancer in Kochi Prefecture

Projected impact of colorectal cancer screening with computerized tomographic colonography on current radiological capacity in Europe

The impact of a primary colorectal cancer screening with computerized tomographic colonography on current radiological capacity is unknown. The multispecialty needs for computerized tomographic examinations raise some doubts on the feasibility of a mass colorectal cancer screening with computerized tomographic colonography. To assess whether the number of available computerized tomographic units in Europe is adequate to cover population screening with computerized tomographic colonography. A mathematical and a Markov model were, respectively, used to assess the number of computerized tomographic colonography procedures needed to be performed each day in the start-up and in the steady-state phases of a colorectal cancer screening programme in Europe. Such outcome was divided for the total number of computerized tomographic machines aged <10 years estimated to be present in the European hospitals. At a simulated 30% compliance, 28 760 130 European people would need to be screened by the 3482 available computerized tomographic units in a 5-year start-up period, corresponding to 6.6 CTC/CT unit/day. Assuming a 10-year repetition of computerized tomographic colonography between 50 and 80 years, the number of computerized tomographic colonography needed to be performed in the steady-state period appeared to be 4.3/CT unit/day. The current radiological capacity may cover the need for a primary colorectal cancer screening with computerized tomographic colonography in a steady state. On the other hand, a substantial implementation of the current computerized tomographic capacity or a synergistic approach with other techniques seems to be necessary for the start-up period.

Screening and early diagnosis of colorectal cancer in China: a 12 year retrospect (1994–2006)

Colorectal cancer is one of the most prevalent malignancies in the world. Chinese researchers and clinical doctors had been working hard in the last 12 years, exploring efficient and convenient methods for screening and early diagnosis. The 12 years research works indicated that SFOBT plus colonoscopy was the best detecting protocol for mass screening of colorectal cancer. Serial combined testing for tumor markers plus colonoscopy is the most commonly used strategy for early diagnosis. However, still no optimum method for early diagnosis was generally accepted by most researchers. Due to intrinsic defects of the techniques, several screening and diagnostic methods should be combined to bring each advantage into full play, in order to elevate the diagnostic level of colorectal cancer.

Mass screening for colorectal cancer: the French program

Mass screening for colorectal cancer: the French program

Noninvasive diagnostic tools in colorectal cancer mass screening

Colorectal cancer is one of the most common malignancies in developed countries. Although guaiac-based fecal occult blood tests have proven their efficacy for screening, they have major drawbacks. Immunochemical fecal occult blood tests are theoretically superior as they can detect very small amounts of hemoglobin, and they are specific to human hemoglobin. Recently many different immunochemical tests have been marketed, with variations in hemoglobin detection limit, mechanism of action, sample collection method, and test development. Molecular tests represent an alternative to fecal blood tests, which have been designed to detect certain fecal DNA mutations, or aberrant gene methylation (either hyper-or hypomethylation). In this review, we discuss a selection of the most significant studies published in the last 3 years regarding noninvasive tools for colorectal cancer screening.

Rates of New or Missed Colorectal Cancers After Colonoscopy and Their Risk Factors: A Population-Based Analysis

The rate of new or missed colorectal cancer (CRC) after colonoscopy and their risk factors in usual practice are unknown. Our objective was to evaluate the rate and risk factors in a population-based study. We analyzed data from the Canadian Institute for Health Information, the Ontario Health Insurance Program, and Ontario Cancer Registry for all patients (> or =20 years of age) with a new diagnosis of right-sided, transverse, splenic flexure/descending, rectal or sigmoid CRC in Ontario from April 1, 1997 to March 31, 2002, who had a colonoscopy within the 3 years before their diagnosis. Patients with new or missed cancers were those whose most recent colonoscopy was 6 to 36 months before diagnosis. We examined characteristics that might be risk factors for new or missed CRC. We identified a diagnosis of CRC in 3288 (right sided), 777 (transverse), 710 (splenic flexure/descending), and 7712 (rectal or sigmoid) patients. The rates of new or missed cancers were 5.9%, 5.5%, 2.1%, and 2.3%, respectively. Independent risk factors for these cancers in men and women were older age; diverticular disease; right-sided or transverse CRC; colonoscopy by an internist or family physician; and colonoscopy in an office. Because having an office colonoscopy and certain patient, procedure, and physician characteristics are independent risk factors for new or missed CRC, physicians must inform patients of the small risk (2% to 6%) of these cancers after colonoscopy. The influence of type of physician and setting on the accuracy of colonoscopy, potentially modifiable risk factors, warrants further study.

Prospective multicenter evaluation of fecal tumor pyruvate kinase type M2 (M2‐PK) as a screening biomarker for colorectal neoplasia

Proliferating cells, particularly the tumor cells, express a dimeric isoenzyme of pyruvate kinase, termed M2-PK. It's a direct target of several oncoproteins; the determination of fecal tumor pyruvate kinase type M2 (M2-PK) might be another promising tool for colorectal cancer (CRC) screening. In this study, we have evaluated fecal M2-PK as a screening biomarker for colorectal neoplasia. It was compared against fecal occult blood (FOB) and colonoscopy. Three hundred and seventeen consecutive subjects from 4 different centers were included. Stool specimens were collected before purgation, processed appropriately and were tested for FOB and quantitatively analyzed for M2-PK. Colonoscopies were performed by experienced endoscopists who were unaware of fecal assay results. At cutoff value of 4 U/ml, fecal M2-PK assay had a sensitivity, specificity, PPV and NPV of 81.1, 86.7, 71.1 and 61.9% respectively for diagnosing CRC whereas FOBT showed a sensitivity of 36.5%, specificity of 92.2%, PPV of 72.9% and NPV of 71.5% for CRC. Such low specificity of fecal M2-PK will lead to unacceptably high number of false positives if it is used for mass CRC screening, leading to unindicated colonoscopies with its associated inconveniences, risks and costs. CRC screening test must have high specificity; a high sensitivity is not as vital. To conclude, M2-PK was found to be a poor screening biomarker for CR neoplasia in a subject population at above average risk based on its prospective comparison with colonoscopy. These marginal performance characteristics do not permit its use as a screening tool for CR neoplasia in present clinical settings.

The reasons of general practitioners for promoting colorectal cancer mass screening in France

Implementation of colorectal cancer (CRC) mass screening is a public health priority. Obtaining the involvement of general practitioners (GPs) is crucial for ensuring participation by the general public. This study elicited GPs' reasons for promoting CRC screening. The method used was discrete choice modeling. Questionnaires with a set of pairs of hypothetical screening scenarios were sent to 700 GPs. Factors influencing GPs' screening practice were found to be: the effectiveness of the screening program, the proportion of false negatives and false positives, and their remuneration. Hence improving screening test sensitivity and setting up specific remuneration for conducting screening would help to increase GPs' participation in CRC screening in France.

COMMUNITY‐BASED MASS SCREENING FOR COLORECTAL CANCER BY A COMBINATION OF FECAL OCCULT BLOOD TESTING AND FLEXIBLE SIGMOIDOSCOPY

Background: There have only been a few large‐scale community‐based reports on the combination of immunological fecal occult blood testing (IFOBT) and flexible sigmoidoscopy (FS). Based on the results of mass screening at our hospital, we investigated the utility of combining IFOBT with FS to detect colorectal cancer (CRC) and analyzed the detection rates of CRC.Subjects and methods: The subjects comprised examinees during mass screening for CRC from 1992 to 2002. Only examinees that underwent the 2‐day IFOBT method were enrolled. During the 11 years, 117 644 subjects had negative 2‐day IFOBT and underwent FS. Cancers that were directly found by FS or by work‐up examinations with negative 2‐day IFOBT were designated as IFOBT‐FS‐detected cancers.Results: The detection rate of CRC was 0.16% (mucosal cancer, 0.13%; invasive cancer, 0.03%) by negative 2‐day IFOBT and FS. It was 0.27% (mucosal cancer, 0.22%; invasive cancer, 0.05%) in first‐time examinees. The detection rate was significantly higher in males than in females, and rates increased with age in both genders. Adverse events included eight cases of ischemic colitis that occurred after FS (incidence rate, 0.0068%). There were no cases of perforation, hemorrhage or infection after endoscopy.Conclusion: Although there are problems in introducing FS into mass screening for CRC, such as cost‐effectiveness, speed of examinations and lack of manpower, FS is expected to prevail because preparation is easier, and it is a shorter and safer procedure than colonoscopy. In particular, a combination of IFOBT with FS is effective and recommended in first‐time examinees and for individuals 50 years and older. Mass screening using the combination of IFOBT and FS provides limited benefit in those who are below 50 years of age.

Evaluation of an immunochemical fecal occult blood test with automated reading in screening for colorectal cancer in a general average‐risk population

Colorectal cancer screening is a high public health priority in all industrialized countries. However, the low sensitivity of the common guaiac screening test (HemoccultII) makes practitioners and public health decision makers reluctant to set up a national screening program. In recent years, immunochemical tests based on the use of a specific antibody have been found to be more sensitive than the HemoccultII test. However, for screening purposes, any gain in sensitivity is of interest only if specificity and positive predictive value are satisfactory. Our aim was to assess the performance of an immunochemical test with an automated reading technique (Magstream 1000) for different hemoglobin content cut-off points. The study was carried out in the general population aged 50-74 years in the geographic area of Cotentin (Normandy, France). From 1 January 2001 to 31 December 2002, 7,421 one-time screening tests (Magstream) were administered by general practitioners and occupational physicians to patients at the end of regular consultations. Colonoscopy was proposed to the 434 people with a positive test. All cancers occurring in the study population between 1 January 2001 and 31 December 2003 were collected by general practitioners, gastroenterologists and the local registry. At the usual positivity threshold (20 ng hemoglobin/ml), screening sensitivity and specificity at 2 years of follow-up with 95% CIs were, respectively, 0.85 (0.72-0.98) and 0.94 (0.94-0.95). If the hemoglobin content cut-off point had been set at 50 ng/ml instead of the usual cut-off, positivity would have been 3.1% and positive predictive value for a cancer or a large adenoma would have been 0.49, with sensitivity of 0.68-0.83 and specificity of 0.97. Our results suggest that use of an immunochemical test with an automated reading technique could improve the prospects for mass-screening for colorectal cancer since it offers a promising alternative to guaiac tests.

Evaluation of mass screening for colorectal cancer based on five-year survival rates using population based cancer registry.

Evaluation of mass screening for colorectal cancer based on five-year survival rates using population based cancer registry.

Mass screening for colorectal cancer: compliance in Almopea Region

Colorectal cancer (CRC) is the second leading cause of cancer-related morbidity and mortality in Europe and the United States. Planning for a CRC screening began in co-operation with local authorities (Pella Prefecture sponsored test kits). Our aims were to develop a screening programme for colorectal cancer using the faecal occult blood test (FOBT) in Almopea province, and to investigate the compliance of local farmers population. Cancer statistics data from Almopea have been analysed and they showed higher colorectal cancer incidence compared to the rest of Greece. We designed a one-time FOBT screening programme on the Surgery Department computer Network, in which we listed 8963 subjects, over 50 years of age. From them, 4189 underwent 3 days FOBT, and the rest were our control group. The method of successive visits to each community by the medical team and educational meeting was chosen. For allocation and gathering of tests, teams of volunteers have been organised. In case of positive FOBT (176 subjects), total colonoscopy was performed. Seventeen (17) polypoids (in 15 patients) and 20 cases of diverticulosis were detected. The compliance of FOBT group was 49% (from 4189). Colonoscopy accepted 89% from 176 patients with positive test. We concluded that our study shows poor compliance of screening population. There is a need for co-operation of medical services, local authorities, media and volunteers support organising.

Compliance with diagnostic examination in mass screening for colorectal cancer

Compliance with diagnostic examination in mass screening for colorectal cancer

Present Situation of Colorectal Cancer Mass Screening and Surgical Treatment in Elderly Patients

Present Situation of Colorectal Cancer Mass Screening and Surgical Treatment in Elderly Patients

Complications of screening flexible sigmoidoscopy

Background & Aims: Flexible sigmoidoscopy (FS) is recommended for mass screening for colorectal cancer (CRC), yet little is known about the risk of adverse events when FS is used in general clinical practice. We aimed to determine the incidence of gastrointestinal complications and acute myocardial infarction (MI) after screening FS. Methods: Northern California Kaiser Permanente Medical Care Program members of average risk for CRC (n = 107,704) who underwent screening FS during 1994 to 1996 (109,534 FS), as part of the Colorectal Cancer Prevention (CoCaP) program. The main outcome measure was hospitalization for gastrointestinal complications or acute MI within 4 weeks of FS. Results: The mean age of subjects was 61 years, and 48.8% were female. Nongastroenterologist physicians, nurses, or physician assistants performed 72% of FS. Overall, 24 persons were hospitalized for a gastrointestinal complication. Of these, 7 were serious (2 perforations, 2 episodes of diverticulitis requiring surgery, 2 cases of bleeding requiring transfusion, and 1 episode of unexplained colitis). In multivariate models, complications were significantly more common in men than in women (odds ratio, 3.34; 95% confidence interval [CI], 1.34–10.13). MI occurred in 33 persons within 4 weeks of FS, but the incidence for this period was similar to that in the subsequent 48 weeks (rate ratio, 0.8; 95% CI, 0.6–1.2). Conclusions: The risk of serious complications after screening FS in this setting appears to be modest. Although MI occurs after FS, the risk during the 4 weeks after the procedure appears to be similar to expectations for persons of screening age.GASTROENTEROLOGY 2002;123:1786-1792

Screening for GI cancer and payment mechanisms

Screening for GI cancer and payment mechanisms

A simple method of detecting K- ras point mutations in stool samples for colorectal cancer screening using one-step polymerase chain reaction/restriction fragment length polymorphism analysis

Background: We examined a technique for detecting point mutations of K- ras codon 12 in stool samples using one-step polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analysis, in order to determine whether it could be used to screen for colorectal cancer. Methods: DNA was extracted from 200-mg stool specimens of 5 healthy controls and 31 colorectal cancer patients. A 107-base-pair fragment of exon 1 of K- ras was amplified by PCR using mismatched primers. PCR products were digested with B st NI and analyzed by gel electrophoresis followed by silver staining. Specificity of one-step PCR/RFLP was examined by using synthetic oligonucleotides. The detection limit of K- ras codon 12 mutations was determined by using SW480 and HT29 cells. Results: The K- ras gene was successfully amplified from all healthy controls and colorectal cancer patients studied. Mutations of K- ras codon 12 were not detected in any of the healthy controls, but were identified in 13 (41.9%) of the 31 patients with colorectal cancer. Mutations were detectable in all six synthetic mutant DNAs, while none were detected among the wild type. The detection limit of this method was ≥0.1%. Conclusions: PCR/RFLP analysis could be used in mass screening for colorectal cancer, because it is highly specific, has a low detection limit, and is simpler than conventional methods for detecting genetic abnormalities.

Surveillance interval of endoscopic examinations for colorectal cancer screening

Background: There have been a few evidence‐based studies concerning the relationship between the length of the surveillance interval of colonoscopic examinations and the risk of colorectal cancer (CRC). The aim of the present study was to assess the appropriate interval between endoscopic examinations for CRC screening in a retrospective cohort study.Methods: The cohort included subjects in whom cancer was not detected at the initial endoscopic examination and in whom endoscopic examination(s) was subsequently performed one or more times. The results of the endoscopic examinations performed in the mass screening for CRC between November 1983 and March 1999 were analyzed. The study end point was the detection of CRC and the detection rates of cancer were assessed among those who underwent examinations at various intervals between successive endoscopic examinations.Results: Among the 117 636 cohort subjects, 63 invasive cancer cases and 112 mucosal cancer cases were found. The odds ratio (OR) for invasive cancer was not significantly elevated even when the interval between successive examinations was over 5 years. The OR for mucosal or invasive cancer was significantly elevated among the subjects in whom the interval between successive examinations was over 5 years (OR, 1.71; 95% confidence interval (CI), 1.07–2.73), than among those in whom the interval was 1 year.Conclusions: Since prolongation of the interval between endoscopic examinations of up to 5 years did not result in any change in the cancer risk among persons who are at average risk for CRC, 5 years may be an adequate interval between endoscopic examinations in the mass screening for CRC.

Reduction of the incidence and mortality of rectal cancer by polypectomy: a prospective cohort study in Haining County.

To reduce the incidence and mortality of rectal cancer and address the hypothesis that colorectal cancer often arise from precursor lesion(s), either adenomas or non-adenomatous polyps, by conducting a population-based mass screening for colorectal cancer in Haining County, Zhejiang, PRC. From 1977 to 1980, physicians screened the population of Haining County using 15 cm rigid endoscopy. Of over 240000 participants, 4076 of them were diagnosed with precursor lesions, either adenomas or non-adenomatous polyps, which were then removed surgically. All individuals with precursor lesions were followed up and reexamined by endoscopy every two to five years up to 1998. After the initial screening, 953 metachronous adenomas and 417 non-adenomatous polyps were detected and removed from the members of this cohort. Further, 27 cases of colorectal cancer were detected and treated. Log-rank tests showed that the survival time among those cancer patients who under went mass screening increased significantly compared to that of other colorectal cancer patients (P<0.0001). According to the population-based cancer registry in Haining County, age-adjusted incidence and mortality of rectal cancer decreased by 41% and 29% from 1977-1981 to 1992-1996, respectively. Observed cumulative 20-year rectal cancer incidence was 31% lower than the expected in the screened group; the mortality due to rectal cancer was 18% lower than the expected in the screened group. Mass screening for rectal cancer and precursor lesions with protocoscopy in the general population and periodical following-up with routine endoscopy for high-risk patients may decrease both the incidence and mortality of rectal cancer.

Stage of extension and treatment for colorectal cancer after a negative test and among non-responders in mass screening with guaiac faecal occult blood test: a French experience.

Despite its proven efficacy in three randomized trials, the relevance of mass screening for colorectal cancer using the guaiac faecal occult blood test is still debated. The low sensitivity of the test and the poor participation rate, especially in France, are major obstacles to its effectiveness. The aim of our study was to characterize cancers occurring after a negative test and among non-participants in the screening programme organized in the French department of Calvados. Cancers in the negative test group had a later stage of extension than subjects testing positively but an earlier stage of extension than cancers in the reference group, which were not different from those of non-responders. The proportion of resection for non-responders was significantly lower than that for participants, whatever the test result (P < 0.001), and lower than that for reference subjects (P < 0.05). There was no difference in treatment between negative and positive responders. Negative responders did not have a delayed cancer diagnosis or a worse condition of treatment than people who were not screened. Low sensitivity reduced the efficacy of colorectal cancer screening but did not seem to increase the potential to do harm.