Screening for colorectal cancer in average-risk populations

Prevalence of colorectal neoplasms in young, average risk individuals: A turning tide between East and West

AIM

To determine the prevalence of colorectal neoplasia in average risk persons 40-59 years of age in Israel and to compare the results with other populations.

METHODS

We reviewed the results of asymptomatic average-risk subjects, aged 40 to 59 years, undergoing their first screening colonoscopy between April 1994 and January 2014. The detection rates of adenoma, advanced adenoma (AA) and colorectal cancer (CRC) were determined in the 40’s and 50’s age groups by gender. The prevalence of lesions was compared between age groups. After meticulous review of the literature, these results were compared to published studies addressing the prevalence of colorectal neoplasia in similar patient groups, in a variety of geographical locations.

RESULTS

We included first screening colonoscopy results of 1750 individuals. The prevalence of adenomas, AA and CRC was 8.3%, 1.0% and 0.2% in the 40-49 age group and 13.7%, 2.4% and 0.2% in the 50-59 age group, respectively. Age-dependent differences in adenoma and AA rates were significant only among men (P < 0.005). Literature review disclosed 17 relevant studies. As expected, in both Asian and Western populations, the risks for overall adenoma and advanced adenoma was significantly higher in the 50's age group as compared to the 40's age group in a similar fashion. The result of the current study were similar to previous studies on Western populations. A substantially higher rate of adenoma, was observed in studies conducted among Asian populations in both age groups.

CONCLUSION

The higher rate of colorectal neoplasia in Asian populations requires further investigation and reconsideration as to the starting age of screening in that population.

SLAP displays tumour suppressor functions in colorectal cancer via destabilization of the SRC substrate EPHA2

The adaptor SLAP is a negative regulator of receptor signalling in immune cells but its role in human cancer is ill defined. Here we report that SLAP is abundantly expressed in healthy epithelial intestine but strongly downregulated in 50% of colorectal cancer. SLAP overexpression suppresses cell tumorigenicity and invasiveness while SLAP silencing enhances these transforming properties. Mechanistically, SLAP controls SRC/EPHA2/AKT signalling via destabilization of the SRC substrate and receptor tyrosine kinase EPHA2. This activity is independent from CBL but requires SLAP SH3 interaction with the ubiquitination factor UBE4A and SLAP SH2 interaction with pTyr594-EPHA2. SRC phosphorylates EPHA2 on Tyr594, thus creating a feedback loop that promotes EPHA2 destruction and thereby self-regulates its transforming potential. SLAP silencing enhances SRC oncogenicity and sensitizes colorectal tumour cells to SRC inhibitors. Collectively, these data establish a tumour-suppressive role for SLAP in colorectal cancer and a mechanism of SRC oncogenic induction through stabilization of its cognate substrates.

Impact of a Multifaceted Intervention on Promoting Adherence to Screening Colonoscopy Among Persons in HIV Primary Care: A Pilot Study

HIV-positive patients have lower colon cancer screening rates and are at increased risk for colon adenocarcinoma. We tested a transdisciplinary prevention model to increase provider and patient adherence to screening colonoscopy. Of 1,339 HIV-positive patients with scheduled clinic appointments during the period September to November 2009, we identified 400 records of eligible patients ≥50 years and retrospectively reviewed for screening colonoscopy referral; if never referred, flagged for referral at next visit. Providers referred 43.5% (174/400) patients and 36.2% (63/174) kept appointment. Within 6 months before the study, 337 patients attended clinic and providers referred 18%. Note that 211/226 patients with flagged records attended clinic at least once during the study 6-month period and providers referred (43.6%). The referral rate for flagged records was significantly different from that for the prior 6 months (p < 0.0001). A randomized trial compared the efficacy of patient decision support versus usual care on screening adherence. Among patients randomized to intervention 17 (51.5%) compared to usual care only 16 (48.5%), intervention group showed significant adherence of 70.6% (12/17) versus 29.4% (5/16), (p = 0.024). In addition, intervention patients had good bowel preparation of 76.9% (10/13) versus usual care 23.1% (3/13), (p = 0.05). This transdisciplinary intervention model significantly increased provider and patient screening colonoscopy behavior.

Prediction rule for estimating advanced colorectal neoplasm risk in average-risk populations in southern Jiangsu Province

OBJECTIVE

The aim of this study was to establish the risk scoring system towards the advanced colorectal neoplasm (CN) risk in the average-risk populations in the southern Jiangsu Province, and to evaluate the screening efficacy.

METHODS

Totally 905 cases of the average-risk populations who received the colonoscopy were selected as the objective. The multivariate logistic regression analysis method was used to establish the scoring system towards the occurrence risk of the advanced tumor, and its screening efficacy was evaluated through the prediction consistency, distinguishing ability and screening accuracy.

RESULTS

The scoring system consisted of five variables, namely age, gender, coronary heart disease, egg intake and stool frequency. The results revealed that it had good prediction consistency (P=0.205) and distinguishing ability [the area under the receiver operating characteristic (ROC) curve was 0.75, with 95% confidence interval (95% CI) of 0.69-0.82]. Thus, 2.5 points was set as the screening cutoff value, and its sensitivity, specificity, accuracy, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio were 93.8%, 47.6%, 50.1%, 9.1%, 99.3%, 1.79 and 0.13, respectively.

CONCLUSIONS

The established scoring system had good screening efficacy, and can be used as the screening tool applying to the CN screening within the average-risk populations in the southern Jiangsu Province.

Derivation and validation of a prediction rule for estimating colorectal neoplasm risk in asymptomatic individuals in southern Jiangsu province

AIM: To develop a prediction rule to stratify risk for colorectal neoplasms in asymptomatic individuals in southern Jiangsu province, and to evaluate its screening efficiency.

METHODS: Asymptomatic persons in southern Jiangsu province who had complete colonoscopy data were included in this study. All participants were asked to complete a questionnaire which covered information on potential risk factors, including demographic characteristics, medical history, smoking, alcohol consumption, dietary intake, and other factors that may be associated with colorectal neoplasms. A multivariable logistic regression method was used to identify independent predictors of colorectal neoplasms. A prediction rule was developed from the logistic regression model by using a regression coefficient-based scoring method, and then internally validated. The screening efficiency of the prediction rule was assessed by its calibration, discrimination, and accuracy.

RESULTS: A total of 905 asymptomatic persons were included in this study. The prediction rule comprised three variables (age, smoking, and alcohol consumption), with scores ranging from 0 to 6. The prediction rule had good calibration (P = 0.093) and good discrimination (area under the receiver operating characteristic curve = 0.65, 95%CI: 0.61-0.69). When a score of 1.5 was used as the screening cutoff value, the sensitivity, specificity, accuracy, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio were 65.1%, 57.2%, 59.9%, 44.4%, 75.7%, 1.52, and 0.61, respectively.

CONCLUSION: The developed prediction rule had good screening efficiency and, thus, can be used as a preliminary method to screen colorectal neoplasms in asymptomatic individuals in southern Jiangsu province.

Colorectal cancer following negative colonoscopy: is 5-year screening the correct interval to recommend?

BACKGROUND

Despite the high sensitivity of screening colonoscopy, polyps and cancers can still go undetected. With the polyp-to-cancer transformation cycle averaging 7-10 years, present guidelines recommend repeat colonoscopy within 10 years after negative screening. However, not all colorectal malignancies follow this decade-long progression. This study evaluates the incidence and pathology of colorectal cancers following a previous negative screening colonoscopy.

METHODS

Records of patients who underwent a colectomy at our institution, from 1998 to 2009, were reviewed retrospectively. A total of 1,784 patient records were screened using exclusion criteria for inclusion in this study. The patients were divided as follows: Group 1 included patients with a negative colonoscopy within the previous 5 years; Group 2 included patients without a previous colonoscopy or with a previous colonoscopy more than 5 years prior. Group 1 patients were evaluated by colonoscopy for anemia, diverticulitis, signs of obstruction, and bleeding. Age, tumor location, operation performed, and pathology findings were recorded. The χ(2) test and paired t test were used for statistical analysis.

RESULTS

A total of 233 patients were included in this study. Group 1 contained 43 patients with a mean age of 73 years (range = 35-94, median = 75). Group 2 had 190 patients with a mean age of 68 years (range = 19-91, median = 70). Group 1 consisted of 18 male and 25 female patients, and Group 2 included 94 male and 96 female patients. Both groups were further classified into the following age categories: <50 years, 50-80 years, and >80 years. Eighteen percent of the total study population had newly discovered colorectal cancer within a 5-year colonoscopy screening period. There were no significant differences in the distribution of the T and N stages between the two groups and no statistically significant differences when the rate of lymphovascular invasion (19 vs. 17 %; p = 0.39) and perineural invasion (7 vs. 11 %; p = 0.58) were compared.

CONCLUSIONS

Within 5 years, 18 % of our study population developed colorectal cancer. Most of these malignancies were found within the 50-80-year age group and located predominantly in the right colon and distally in the sigmoid and rectum. While distal cancers may be visualized by flexible sigmoidoscopy, those located more proximally may be missed, necessitating the need for a full colonoscopy. Although staging was similar between the two groups, Group 1 tumors were less aggressive despite having appeared within 5 years. As a result of our incidence of colorectal cancer within a 5-year interval, a shorter period for routine colonoscopy may be considered.

Unintended consequences of health information technology: evidence from veterans affairs colorectal cancer oncology watch intervention

PURPOSE

We evaluated the Colorectal Cancer (CRC) Oncology Watch intervention, a clinical reminder implemented in Veterans Integrated Service Network 7 (including eight hospitals) to improve CRC screening rates in 2008.

PATIENTS AND METHODS

Veterans Affairs (VA) administrative data were used to construct four cross-sectional groups of veterans at average risk, age 50 to 64 years; one group was created for each of the following years: 2006, 2007, 2009, and 2010. We applied hospital fixed effects for estimation, using a difference-in-differences model in which the eight hospitals served as the intervention sites, and the other 121 hospitals served as controls, with 2006 to 2007 as the preintervention period and 2009 to 2010 as the postintervention period.

RESULTS

The sample included 4,352,082 veteran-years in the 4 years. The adherence rates were 37.6%, 31.6%, 34.4%, and 33.2% in the intervention sites in 2006, 2007, 2009, and 2010, respectively, and the corresponding rates in the controls were 31.0%, 30.3%, 32.3%, and 30.9%. Regression analysis showed that among those eligible for screening, the intervention was associated with a 2.2-percentage point decrease in likelihood of adherence (P < .001). Additional analyses showed that the intervention was associated with a 5.6-percentage point decrease in likelihood of screening colonoscopy among the adherent, but with increased total colonoscopies (all indicators) of 3.6 per 100 veterans age 50 to 64 years.

CONCLUSION

The intervention had little impact on CRC screening rates for the studied population. This absence of favorable impact may have been caused by an unintentional shift of limited VA colonoscopy capacity from average-risk screening to higher-risk screening and to CRC surveillance, or by physician fatigue resulting from the large number of clinical reminders implemented in the VA.

Effect of comorbid conditions on adherence to colorectal cancer screening

Potential barriers to colorectal cancer (CRC) screening include preexisting medical conditions (comorbidities), physician recommendation, psychosocial factors, and screening preparedness. This study's purpose was to investigate the impact of comorbid conditions on CRC screening among African Americans. A stage-matched randomized clinical trial was performed. Asymptomatic African Americans over age 50, with a primary care physician, and eligible for CRC screening were recruited at The Mount Sinai Hospital from 2005 to 2008. One hundred sixty-one patients were assessed for referral for, and completion of, CRC screening, comorbid conditions, "readiness to change," and number of physician visits within the observation period. Data was compared to a pretrial index to predict the likely effect of comorbid conditions on CRC screening. One hundred fifty-nine patients completed the study; 108 (68.9%) were referred for and 34 (21.2%) completed CRC screening. No demographic characteristics were associated with CRC screening completion. CRC screening referrals were similar for all patients, regardless of comorbidities or clinical visits. Comorbidities rated as having extreme influence on CRC screening showed a trend toward lower screening rates. There was a significant increase in screening rates among participants in advanced stages of readiness at enrollment. These data suggest that while comorbidities did not predict colonoscopy completion, they may play a role in concert with other factors. This is the only study to assess the effect of screening colonoscopy in an African American primary care setting. We must continue to explore interventions to narrow the disparate gap in screening and mortality rates.

Validity of the process of change for colorectal cancer screening among African Americans

BACKGROUND

Process of change (POC) is a construct of the transtheoretical model that proposes to promote healthy behaviors.

PURPOSE

African Americans participate in colorectal cancer (CRC) screening less often than whites, while disease onset is younger, and incidence and mortality from CRC are higher.

METHODS

POC items for CRC screening were administered to 158 African Americans, the majority of whom were female (75.9%) and were not employed (85.4%). Confirmatory factor analysis was used to validate four factors reflecting the POC sub-domains.

RESULTS

Support of the factor validity of the POC with internal consistency of standardized alpha for the four factors was found. A logistic regression showed predictive validity in predicting current screening stage for two of the four sub-domains.

CONCLUSION

These data support the application of the POC to prediction of CRC screening intention among African Americans.

Colorectal cancer screening, perceived discrimination, and low-income and trust in doctors: a survey of minority patients

Background

Completion of colorectal cancer (CRC) screening testing is lower among low-income and minority groups than the population as a whole. Given the multiple cancer screening health disparities known to exist within the U.S., this study investigated the relationship between perceived discrimination, trust in most doctors, and completion of Fecal Occult Blood Testing (FOBT) among a low-income, minority primary care population in an urban setting.

Methods

We recruited a convenience sample of adults over age 40 (n = 282) from a federally qualified community health center (70% African American). Participants completed a survey which included measures of trust in most doctors, perceived discrimination, demographics and report of cancer screening.

Results

Participants reported high levels of trust in most doctors, regardless of sex, race, education or income. High trust was associated with low perceived discrimination (p < 0.01). The trend was for older participants to express more trust (p = 0.09) and less perceived discrimination (p < 0.01). Neither trust nor discrimination was associated with race or education. Trust was higher among participants over 50 who were up-to-date on FOBT screening vs. those who were not (31 vs. 29 (median), p < 0.05 by T-test). Among those over 50, up-to-date FOBT screening was nearly associated with high trust (p < 0.06; 95% CI 0.99, 1.28) and low perceived discrimination (p < 0.01; 95% CI 0.76, 0.96). Nevertheless, in multivariate-modeling, age and income explained FOBT completion better than race, trust and discrimination.

Conclusion

Perceived discrimination was related to income, but not race, suggesting that discrimination is not unique to minorities, but common to those in poverty. Since trust in most doctors trended toward being related to age, FOBT screening could be negatively influenced by low trust and perceived discrimination in health care settings. A failure to address these issues in middle-aged, low income individuals could exacerbate future disparities in CRC screening.

NGX6 inhibits AP-1 and Ets-1 expression and down-regulates cyclin D1 in human colorectal cancer

Colorectal cancer (CRC) is a common malignant tumor that is associated with an increased incidence of morbidity and mortality. Nasopharyngeal carcinoma-associated gene 6 (NGX6) is a novel candidate suppressor gene of tumor metastasis, which is down-regulated in CRC. In the present study, we constructed a colorectal tissue microarray to examine the expression profiles of NGX6, phospho-c-Jun N-terminal kinase (p-JNK), and phospho-extracellular signal-regulated kinase (p-ERK ) in CRC tissues. We found that the NGX6 expression was lower in CRC tissues and metastatic lymph nodes, whereas the expressions of p-JNK and p-ERK were higher in CRC tissues, than in normal intestinal mucosa. The expressions of NGX6, p-JNK, and p-ERK were associated with the clinical pathological features of colorectal tissues. NGX6 overexpression inhibited the activation and nuclear translocation of JNK1, which led to an accumulation of p-JNK in the cytoplasm, but did not inhibit the activation and nuclear translocation of ERK1/2. NGX6 also inhibited the expression of the transcription factors AP-1 (c-jun and c-fos) and Ets-1. In addition, NGX6 overexpression decreased the expression of cyclin D1 and dramatically suppressed the transcriptional efficiency of the cyclin D1 promoter. We propose that NGX6 expression is lost in the multistep process of human colorectal carcinogenesis. Its overexpression can inhibit the expression of transcription factors AP-1 and Ets-1, and down-regulate the transcriptional activity of the cyclin D1 promoter in human CRC.

In vitro/in vivo biorecognition of lectin-immobilized fluorescent nanospheres for human colorectal cancer cells

Peanut agglutinin (PNA)-immobilized polystyrene nanospheres with surface poly(N-vinylacetamide) (PNVA) chains encapsulating coumarin 6 were designed as a novel colonoscopic imaging agent. PNA was a targeting moiety that binds to beta-D-galactosyl-(1-3)-N-acetyl-D-galactosamine, which is the terminal sugar of the Thomsen-Friedenreich antigen that is specifically expressed on the mucosal side of colorectal cancer cells. PNVA was immobilized with the aim of reducing nonspecific interactions between imaging agents and normal tissues. Coumarin 6 was encapsulated into nanosphere cores to provide endoscopically detectable fluorescence intensity. After incubation of imaging agents with human cells, the fluorescence intensity of imaging agent-bound cells was estimated quantitatively. The average fluorescence intensity of any type of colorectal cancer cell used in this study was higher than that of small intestinal epithelial cells that had not exposed the carbohydrate. The in vivo performance of imaging agents was subsequently evaluated using a human colorectal cancer orthotopic animal model. Imaging agent-derived strong fluorescence was observed at several sites of the large intestinal mucosa in the tumor-implanted nude mice after the luminal side of the colonic loop was contacted with imaging agents. In contrast, when mice that did not undergo tumor implantation were used, the fluorescence intensity on the mucosal surface was extremely low. Data indicated that imaging agents bound to colorectal cancer cells and the cancer cell-derived tumors with high affinity and specificity.

A phase II trial of lomeguatrib and temozolomide in metastatic colorectal cancer

To evaluate the tumour response to lomeguatrib and temozolomide (TMZ) administered for 5 consecutive days every 4 weeks in patients with metastatic colorectal carcinoma. Patients with stage IV metastatic colorectal carcinoma received lomeguatrib (40 mg) and TMZ (50–200 mg m⁻²) orally for 5 consecutive days every 4 weeks. Response was determined every two cycles. Pharmacokinetics of lomeguatrib and TMZ as well as their pharmacodynamic effects in peripheral blood mononuclear cells (PBMC) were determined. Nineteen patients received 49 cycles of treatments. Despite consistent depletion of O⁶-methylguanine-DNA methyltransferase in PBMC, none of the patients responded to treatment. Three patients had stable disease, one for the duration of the study, and no fall in carcinoembryonic antigen was observed in any patient. Median time to progression was 50 days. The commonest adverse effects were gastrointestinal and haematological and these were comparable to those of TMZ when given alone. This combination of lomeguatrib and TMZ is not efficacious in metastatic colorectal cancer. If further studies are to be performed, emerging data suggest that higher daily doses of lomeguatrib and a dosing period beyond that of TMZ should be evaluated.

Computed tomographic colonography: clinical value

Computed tomographic colonography (CTC) has the potential to reliably detect polyps in the colon. Its clinical value is accepted for several indications. The main target is screening asymptomatic people for colorectal cancer (CRC). As in large multi-centre trials controversial results were obtained, acceptance of this indication on a large scale is still pending. Agreement exists that in experienced hands screening can be performed with CTC. This emphasizes the importance of adequate and intensive training. Besides this, other problems have to be solved. A low complication profile is mandatory. Perforation rate is very low. Ultra-low dose radiation should be used. When screening large patient cohorts, CTC will need a time-efficient and cost-effective management without too many false positives and additional exploration. Can therefore a cut-off size of polyp detection safely be installed? Is the flat lesion an issue? Can extra-colonic findings be treated efficiently? A positive relationship with the gastro-enterologists will improve the act of screening. Improvements of scanning technique and software with dose reduction, improved 3D visualisation methods and CAD are steps in the good direction. Finally, optimisation of laxative-free CTC could be invaluable in the development of CTC as a screening tool for CRC.

Genetic and environmental risk assessment for colorectal cancer risk in primary care practice settings: a pilot study

PURPOSE

The assessment of genetic variants and environmental exposures (i.e., genetic and environmental risk assessment) may permit individualized risk stratification for common diseases as part of routine care. A pilot study was conducted to assess the uptake of, and response to, testing for colorectal cancer risk among average risk patients in primary care practice settings.

METHODS

Physicians in primary care practices identified patients eligible for colorectal cancer screening and referred them to the study. Research staff administered a baseline survey to consenting patients. At a scheduled office visit, participants underwent decision counseling with a trained nurse educator to facilitate informed decision making about being tested for methylene tetrahydrofolate reductase status and red blood cell folate level. Combined assessment can stratify colorectal cancer risk. Test results were disclosed within 2 weeks after the visit. Postvisit and 1-month endpoint surveys were administered. Univariable analyses of survey data were performed to assess changes from baseline in genetic and environmental risk assessment and colorectal cancer screening-related knowledge and perceptions.

RESULTS

Of the 57 patients who were referred to the study, 25 (44%) consented to participate, and all but one were tested. Participant knowledge about genetic and environmental risk assessment and colorectal cancer screening, perceived colorectal cancer screening response efficacy, and perceived social support for colorectal cancer screening increased significantly from baseline. Participants reported low levels of intrusive thoughts about CRC.

CONCLUSION

Knowledge and favorable perceptions of colorectal cancer screening increased, as did knowledge about genetic and environmental risk assessment, after exposure to the study intervention. Further research is needed to assess genetic and environmental risk assessment uptake and impact at the population level.

Virtual colonoscopy training and accreditation: a national survey of radiologist experience and attitudes in the UK

AIM

Expert consensus recommends directed training and possibly in the future, formal accreditation before independent virtual colonoscopy (VC) reporting. We surveyed radiologists' experience of VC training, compared with barium enema, and assessed attitudes towards accreditation.

MATERIALS AND METHODS

A questionnaire was sent to 78 consultant radiologists from 72 centres (65 National Health Service hospitals; seven independent primary screening centres) offering a VC service.

RESULTS

Fifty-four (69%) eligible radiologists responded. They had interpreted 18,152 examinations (range 3-1500) in total versus 232,350 (13 times more) barium enemas. Twenty-two (41%) deemed their VC training as inadequate [including five (45%) of screening centre radiologists], and only 14 (26%) had attended a training workshop due to lack of availability (54%) or financial/study leave constraints (24%). Eleven (20%) radiologists routinely double-reported VC examinations versus 37 (69%) barium enemas, yet 21 (39%) considered requirements for VC training were greater than barium enema. Thirty-eight (70%) favoured accreditation beyond internal audit for VC versus 15(28%) for barium enema. Of these 38, seven (18%) favoured "one-off," and 18 (47%) periodic testing, with 16 (42%) favouring external audit alone or in combination with testing. Overall, 42 (78%) considered specific accreditation for reporting screening examinations appropriate and 45 (83%) respondents preferred a national radiological organization to regulate such a scheme.

CONCLUSION

There is wide variability in reporting experience and recommendations for VC training have not been widely adopted, in part due to limited access to dedicated workshops. UK radiologists are generally in favour of VC accreditation, governed by a national radiology organization.