Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology

Editorial: It's time to make organized colorectal cancer screening convenient and easy for patients

Colorectal cancer (CRC) screening is widely recommended, but underused. To increase screening rates, we need to implement organized and population-based systems to promote CRC screening among people in a single region, health plan, or health system. This is ideally accomplished using fecal immunochemical tests (FITs), which can be sent through a mass mailing. The study by Levi and colleagues shows that patients using aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), anti-platelet agents, or anti-coagulants do not need to stop these medications while doing the fecal collection. This makes the testing more convenient for patients, and avoids the risk of adverse cardiovascular events caused by stopping these medications.

A pooled analysis of advanced colorectal neoplasia diagnoses after colonoscopic polypectomy

BACKGROUND & AIMS

Limited data exist regarding the actual risk of developing advanced adenomas and cancer after polypectomy or the factors that determine risk.

METHODS

We pooled individual data from 8 prospective studies comprising 9167 men and women aged 22 to 80 with previously resected colorectal adenomas to quantify their risk of developing subsequent advanced adenoma or cancer as well as identify factors associated with the development of advanced colorectal neoplasms during surveillance.

RESULTS

During a median follow-up period of 47.2 months, advanced colorectal neoplasia was diagnosed in 1082 (11.8%) of the patients, 58 of whom (0.6%) had invasive cancer. Risk of a metachronous advanced adenoma was higher among patients with 5 or more baseline adenomas (24.1%; standard error, 2.2) and those with an adenoma 20 mm in size or greater (19.3%; standard error, 1.5). Risk factor patterns were similar for advanced adenomas and invasive cancer. In multivariate analyses, older age (P < .0001 for trend) and male sex (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.19-1.65) were associated significantly with an increased risk for metachronous advanced neoplasia, as were the number and size of prior adenomas (P < .0001 for trend), the presence of villous features (OR, 1.28; 95% CI, 1.07-1.52), and proximal location (OR, 1.68; 95% CI, 1.43-1.98). High-grade dysplasia was not associated independently with metachronous advanced neoplasia after adjustment for other adenoma characteristics.

CONCLUSIONS

Occurrence of advanced colorectal neoplasia is common after polypectomy. Factors that are associated most strongly with risk of advanced neoplasia are patient age and the number and size of prior adenomas.

Influence of primary care use on population delivery of colorectal cancer screening

OBJECTIVE

Colorectal cancer (CRC) screening is commonly initiated during primary care visits. Thus, at the population level, limited primary care attendance may constitute a substantial barrier to CRC screening uptake. Within a defined population, we quantified the percent of CRC screening underuse that is potentially explained by low use of primary care visits.

METHODS

Among 48,712 adults ages 50 to 78 years eligible for CRC screening within a Washington state health plan, we estimated the degree to which a lack of CRC screening in 2002 to 2003 (fecal occult blood testing, sigmoidoscopy, or colonoscopy) was attributable to low primary care use, expressed as the population attributable risk percent (PAR%) associated with 0 to 3 primary care visits during the 2-year period.

RESULTS

In analyses adjusted for age, comorbidity, nonprimary care visit use, and prior preventive service use, low primary care use in 2002 to 2003 was strongly associated with a lack of CRC screening among both women and men. However, a majority of unscreened women and men had > or =4 primary care visits. Thus, whether low primary care use was defined as 0, 0 to 1, 0 to 2, or 0 to 3 primary care visits, the PAR% associated with low primary care use was large in neither women (range, 3.0-6.8%) nor men (range: 5.6-11.5%).

CONCLUSIONS

Health plan outreach efforts to encourage primary care attendance would be unlikely to substantially increase population uptake of CRC screening. In similar settings, resources might be more fruitfully devoted to the optimization of screening delivery during primary care visits that patients already attend.

High detection rates of colorectal neoplasia by stool DNA testing with a novel digital melt curve assay

BACKGROUND & AIMS

Current stool DNA tests identify about half of individuals with colorectal cancers and miss most individuals with advanced adenomas. We developed a digital melt curve (DMC) assay to quantify low-abundance mutations in stool samples for detection of colorectal neoplasms and compared this test with other approaches.

METHODS

We combined a melt curve assay with digital polymerase chain reaction and validated the quantitative range. We then evaluated its ability to detect neoplasms in 2 clinical studies. In study I, stool samples from patients with colorectal tumors with known mutations (KRAS, APC, BRAF, TP53) were assayed. In study II, archived stool samples from patients with advanced adenomas containing known KRAS mutations were assayed, along with controls. Results were compared with those from the stool DNA test PreGenPlus (Exact Sciences, Marlborough, MA), Hemoccult, and HemoccultSensa (both Beckman-Coulter, Fullerton, CA).

RESULTS

The DMC assay detected samples in which only 0.1% of target genes were mutated. In study I, the DMC assay detected known mutations in 28 (90%) of 31 tumor samples and 6 (75%) of 8 advanced adenoma samples. In study II, the DMC assay detected 16 (59%) of 27 advanced adenoma samples that contained KRAS mutations, compared with 7% with the Hemoccult, 15% with the HemoccultSensa, and 26% with the PreGenPlus assays (P < .05 for each, compared with the DMC assay); specificities did not differ significantly.

CONCLUSIONS

The DMC assay has a high level of sensitivity in detecting individuals with colon neoplasms and is better than current stool screening methods in detecting those with advanced adenomas. Further studies are indicated.

Offering annual fecal occult blood tests at annual flu shot clinics increases colorectal cancer screening rates

PURPOSE

We wanted to determine whether providing home fecal occult blood test (FOBT) kits to eligible patients during influenza inoculation (flu shot) clinics can contribute to higher colorectal cancer screening (CRCS) rates.

METHODS

The study was time randomized. On 8 dates of an annual flu shot clinic at the San Francisco General Hospital, patients were offered flu shots as usual (control group) and on 9 other dates, patients were offered both flu shots and FOBT kits (intervention group).

RESULTS

The study included 514 patients aged 50 to 79 years, with 246 in the control group and 268 in the intervention group. At the conclusion of flu season, FOBT screening rates increased by 4.4 percentage points from 52.9% at baseline to 57.3% (P = .07) in the control group, and increased by 29.8 percentage points from 54.5% to 84.3% (P <.001) in the intervention group, with the change among intervention participants 25.4 percentage points greater than among control participants (P value for change difference <.001). Among patients initially due for CRCS, 20.7% in the control group and 68.0% in the intervention group were up-to-date at the conclusion of the study (P <.001). In multivariate analyses, the odds ratio for becoming up-to-date with screening in the intervention group (vs the control group) was 11.3 (95% CI, 5.8-22.0).

CONCLUSIONS

Offering FOBT kits during flu shot clinics dramatically increased the CRCS rate for flu shot clinic attendees. Pairing home FOBT kits with annual flu shots may be a useful strategy to improve CRCS rates in other primary care or public health settings.

Colorectal cancer screening among users of county health centers and users of private physician practices

OBJECTIVE

We examined use of colorectal cancer (CRC) screening exam modalities among county health centers and private physician offices, where both were located in the same geographic area.

METHODS

We surveyed 500 county health center registrants and 570 private physician patients, aged 52-75 years. We administered telephone surveys during 2004 to examine relationships among sociodemographic characteristics; perceived barriers to screening with fecal occult blood test (FOBT), sigmoidoscopy, and colonoscopy; and self-reported receipt of each exam.

RESULTS

FOBT was more frequent among county health center registrants; sigmoidoscopy and colonoscopy were more frequent among private physician patients (p < 0.001). County health center registrants less frequently cited no physician recommendation as a barrier to FOBT, but more frequently cited no recommendation as a barrier to sigmoidoscopy and colonoscopy, compared with private physician patients (p < or = 0.02). Among county health center registrants, better health insurance coverage was associated with lower odds of FOBT and higher odds of screening endoscopy; perceived barriers were associated with lower odds of screening (p < 0.02). Among private physician patients, we noted an association between perceived barriers to screening and lower odds of any screening (p < 0.001).

CONCLUSIONS

Overall, CRC screening among county health center and private physician patient samples compared favorably with overall New York and U.S. rates. Although prior studies using national data suggested that screening rates were equivalent in county health center and private physician primary care settings, we found exam-specific differences in patient-reported screening endoscopy among our two patient samples. Understanding factors that contribute to differences in CRC screening between primary care settings is important for ensuring equal access to CRC screening options for all patients.

Reasons patients with a positive fecal occult blood test result do not undergo complete diagnostic evaluation

PURPOSE

Screening for fecal occult blood reduces colorectal cancer mortality by identifying patients with positive results for complete diagnostic evaluation (CDE). CDE rates are suboptimal, however. We sought to determine common reasons for nonperformance of a CDE as recorded by the primary care physician.

METHODS

We undertook a descriptive analysis of reasons reported by physicians for nonperformance of CDE in a nested sample of patients with positive fecal occult blood test (FOBT) results from a randomized controlled trial designed to evaluate the impact of a physician intervention (CDE reminder-feedback and educational outreach) on recommendation and performance rates in primary care practices. Inspection of administrative data for 1,468 patients with positive results showed that 661 (45%) did not undergo CDE. We reviewed patient follow-up forms, which were completed by physicians for patients who did not have a CDE, to identify reasons for nonperformance.

RESULTS

Nonperformance of CDE was due to physician decision for 217 patients (33%). In 123 patients (19%), reasons for nonperformance were compatible with the guidelines, and in 94 patients (14%), they were not. Reasons wholly or partially due to factors other than physician decision were noted in 212 patients (32%); physician action was considered to be appropriate in these patients. For the 232 patients (35%) without a clearly documented reason for CDE nonperformance, the appropriateness of the physicians' action could not be determined.

CONCLUSIONS

Decision making by primary care physicians had a major effect on nonperformance of CDE after a positive FOBT result. Colorectal cancer screening programs should include guidance for physicians about when a CDE should and should not be performed.

A risk profile for advanced proximal neoplasms on diagnostic colonoscopy

The capacity for colonoscopy is limited and a method to prioritize patients for diagnostic colonoscopy is needed in health care centers. A retrospective cross-sectional cohort study was carried out in county and community endoscopy centers, which included 1,065 county and 279 community patients aged > or = 40 years undergoing diagnostic colonoscopy. We constructed a risk profile for proximal advanced neoplasms on diagnostic colonoscopy at the county center based on the size of the regression coefficients for independent risk factors from logistic regression. An advanced neoplasm was defined as one of size > or = 1 cm or containing villous histology, high-grade dysplasia, or cancer. In our county colonoscopy population (n = 929 after exclusions), the stepwise logistic regression analysis identified age > or = 60 years (adjusted odds ratio [AOR]: 2.60; 95% confidence interval [CI]:1.14, 6.14), iron deficiency anemia (AOR: 4.74; 95% CI: 2.07, 11.34), and an advanced neoplasm in the recto-sigmoid (AOR: 6.01; 95% CI: 2.02, 16.00) as the statistically significant predictors of an advanced proximal neoplasm. In the county population, the prevalence rates of an advanced proximal neoplasm and proximal high-grade dysplasia/cancer in the low-risk group were 0.71% (95% CI: 0.15, 2.05) and 0.24% (95% CI: 0.01, 1.31), respectively. Avoiding colonoscopy in this group would increase the capacity for colonoscopy by 46% in the higher risk groups. In a disparate community population (n = 237 after exclusions), this scoring system had a goodness-of-fit test showing high concordance (P = 0.51). This clinical profile stratified the risk for an advanced neoplasm proximal to the sigmoid in patients undergoing diagnostic colonoscopy. It identified a large subset of low-risk patients.

Colorectal cancer risk prediction tool for white men and women without known susceptibility

PURPOSE

Given the high incidence of colorectal cancer (CRC), and the availability of procedures that can detect disease and remove precancerous lesions, there is a need for a model that estimates the probability of developing CRC across various age intervals and risk factor profiles.

METHODS

The development of separate CRC absolute risk models for men and women included estimating relative risks and attributable risk parameters from population-based case-control data separately for proximal, distal, and rectal cancer and combining these estimates with baseline age-specific cancer hazard rates based on Surveillance, Epidemiology, and End Results (SEER) incidence rates and competing mortality risks.

RESULTS

For men, the model included a cancer-negative sigmoidoscopy/colonoscopy in the last 10 years, polyp history in the last 10 years, history of CRC in first-degree relatives, aspirin and nonsteroidal anti-inflammatory drug (NSAID) use, cigarette smoking, body mass index (BMI), current leisure-time vigorous activity, and vegetable consumption. For women, the model included sigmoidoscopy/colonoscopy, polyp history, history of CRC in first-degree relatives, aspirin and NSAID use, BMI, leisure-time vigorous activity, vegetable consumption, hormone-replacement therapy (HRT), and estrogen exposure on the basis of menopausal status. For men and women, relative risks differed slightly by tumor site. A validation study in independent data indicates that the models for men and women are well calibrated.

CONCLUSION

We developed absolute risk prediction models for CRC from population-based data, and a simple questionnaire suitable for self-administration. This model is potentially useful for counseling, for designing research intervention studies, and for other applications.

Effect of language on colorectal cancer screening among Latinos and non-Latinos

BACKGROUND

Language barriers among some Latinos may contribute to the lower rates of colorectal cancer (CRC) screening between Latinos and non-Latino Whites. The purpose of this study was to examine the relationship between language and receipt of CRC screening tests among Latinos and non-Latinos using a geographically diverse, population-based sample of adults.

METHODS

Cross-sectional analysis of the Behavioral Risk Factor Surveillance System (BRFSS) survey. Analysis included adults age 50 years and older, who completed the 2006 BRFSS in a state that recorded data from English- and Spanish-speaking participants.

RESULTS

The primary outcome measure was receipt of colorectal screening tests (fecal occult blood testing within prior 12 months and/or lower endoscopy within 10 years). Of the 99,895 respondents included in the study populations, 33% of Latinos responding-in-Spanish reported having had CRC testing, whereas 51% of Latinos responding-in-English and 62% of English-speaking non-Latinos reported test receipt. In multivariable analysis, compared with non-Latinos, Latinos responding-in-English were 16% less likely to have received CRC testing [odds ratio (OR), 0.84; 95% confidence interval (95% CI), 0.73-0.98], and Latinos responding-in-Spanish were 43% less likely to have received CRC testing (OR, 0.57; 95% CI, 0.44-0.74). Additionally, compared with Latinos responding-in-English, Latinos responding-in-Spanish were 36% less likely to have received CRC testing (OR, 0.64; 95% CI, 0.48-0.84).

CONCLUSION

Latinos responding to the 2006 BRFSS survey in Spanish had a significantly lower likelihood of receiving CRC screening tests compared with non-Latinos and to Latinos responding-in-English. Based on this analysis, Spanish language use is negatively associated with CRC screening and may contribute to disparities in CRC screening.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Testicular, Prostate, Colorectal, Breast, and Ovarian Cancers

Background: Updated National Academy of Clinical Biochemistry (NACB) Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed.

Methods: Published reports relevant to use of tumor markers for 5 cancer sites—testicular, prostate, colorectal, breast, and ovarian—were critically reviewed.

Results: For testicular cancer, α-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase are recommended for diagnosis/case finding, staging, prognosis determination, recurrence detection, and therapy monitoring. α-Fetoprotein is also recommended for differential diagnosis of nonseminomatous and seminomatous germ cell tumors. Prostate-specific antigen (PSA) is not recommended for prostate cancer screening, but may be used for detecting disease recurrence and monitoring therapy. Free PSA measurement data are useful for distinguishing malignant from benign prostatic disease when total PSA is &lt;10 μg/L. In colorectal cancer, carcinoembryonic antigen is recommended (with some caveats) for prognosis determination, postoperative surveillance, and therapy monitoring in advanced disease. Fecal occult blood testing may be used for screening asymptomatic adults 50 years or older. For breast cancer, estrogen and progesterone receptors are mandatory for predicting response to hormone therapy, human epidermal growth factor receptor-2 measurement is mandatory for predicting response to trastuzumab, and urokinase plasminogen activator/plasminogen activator inhibitor 1 may be used for determining prognosis in lymph node–negative patients. CA15-3/BR27–29 or carcinoembryonic antigen may be used for therapy monitoring in advanced disease. CA125 is recommended (with transvaginal ultrasound) for early detection of ovarian cancer in women at high risk for this disease. CA125 is also recommended for differential diagnosis of suspicious pelvic masses in postmenopausal women, as well as for detection of recurrence, monitoring of therapy, and determination of prognosis in women with ovarian cancer.

Conclusions: Implementation of these recommendations should encourage optimal use of tumor markers.

Rates of new or missed colorectal cancer after barium enema and their risk factors: a population-based study

OBJECTIVE

Double-contrast barium enema (DCBE) is widely used in clinical practice to detect colorectal cancer (CRC). Our objective was to evaluate the rate of new or missed CRC following DCBE and the associated risk factors in a population-based study.

METHODS

All patients (> or =20 yr old) with a new diagnosis of CRC between April 1, 1997, and March 31, 2004, in Ontario were identified. Data were extracted from the Ontario Health Insurance Program, the Canadian Institute for Health Information, the Registered Persons Database and the Ontario Cancer Registry. Patients who had a DCBE examination 36 months prior to the diagnosis of CRC were divided into two groups: detected cancers (DCBE within 6 months prior to diagnosis) and new or missed cancers (DCBE 6-36 months prior to diagnosis). Multivariate analysis was used to evaluate factors associated with new or missed CRC.

RESULTS

We identified 13,849 patients who had a DCBE 36 months prior to the diagnosis of CRC. The overall rate of new or missed cancers following DCBE was 22.4%. Independent risk factors for new or missed cancers were older age, female sex, previous abdominal or pelvic surgery, diverticular disease, right-sided CRC, and having the DCBE in an office setting.

CONCLUSIONS

Physicians who use DCBE to evaluate the colon must inform their patients that if a cancer is present, there is an approximately one in five chance that it will be missed. Given the recent endorsement of CT colonography by the U.S. Multi-Society Task Force on Colorectal Cancer as an option for CRC screening, it may be time to reconsider the use of DCBE to detect CRC.

Screening colonoscopy for colorectal cancer in asymptomatic people: a meta-analysis

OBJECTIVE

The preferred method for screening asymptomatic people for colorectal cancer (CRC) is colonoscopy, according to the new American guidelines. The aim of our study was to perform a meta-analysis of the prospective cohorts using total colonoscopy for screening this population for CRC. We looked for the diagnostic yield of the procedure as well as for its safety in a screening setting.

METHODS

We included papers with more than 500 participants and only those reporting diagnostic yield of adenoma (and/or advanced adenoma) and CRC. Nested analysis were performed for secondary endpoints of complications and CRC stages when this information was available. All analyses were performed with StatDirect Statistical software, version 2.6.1 ( http://www.statsdirect.com ).

RESULTS

Our search yielded ten studies of screening colonoscopy conducted in asymptomatic people that met our inclusion criteria, with a total of 68,324 participants. Colonoscopy was complete and reached the cecum in 97% of the procedures. Colorectal cancer was found in 0.78% of the participants (95% confidence interval 0.13-2.97%). Stage I or II were found in 77% of the patients with CRC. Advanced adenoma was found in 5% of the cases (95% confidence interval 4-6%). Complications were rare and described in five cohorts. Perforation developed in 0.01% of the cases (95% confidence interval 0.006-0.02%) and bleeding in 0.05% (95% confidence interval 0.02-0.09%).

CONCLUSIONS

Our findings support the notion that colonoscopy is feasible and a suitable method for screening for CRC in asymptomatic people.

Clinical management of small (6- to 9-mm) polyps detected at screening CT colonography: a cost-effectiveness analysis

OBJECTIVE

The primary aim of this model analysis was to compare the clinical and economic impacts of immediate polypectomy versus 3-year CT colonography (CTC) surveillance for small (6- to 9-mm) polyps detected at CTC screening.

MATERIALS AND METHODS

A decision analysis model was constructed incorporating the expected advanced neoplasia prevalence, frequency of measurable growth, colorectal cancer (CRC) prevalence and risk, CTC performance, and costs related to CRC screening and treatment. CRC risk was assumed to be independent of advanced adenoma size, which intentionally overestimates the risk related to small polyps. Clinical effectiveness and costs for 3-year CTC surveillance versus immediate colonoscopic polypectomy were compared for a concentrated cohort of patients with 6- to 9-mm polyps. For the CTC surveillance strategy, only cases with measurable growth (> or = 1 mm) at follow-up CTC were referred for polypectomy.

RESULTS

Without any intervention, the estimated 5-year CRC death rate from 6- to 9-mm polyps in this concentrated cohort was 0.08%, which is a sevenfold decrease over the 0.56% CRC risk for the general unselected screening population. The death rate was further reduced to 0.03% with the CTC surveillance strategy and to 0.02% with immediate colonoscopy referral. However, for each additional cancer-related death prevented with immediate polypectomy versus CTC follow-up, 9,977 colonoscopy referrals would be needed, resulting in 10 additional perforations and an incremental cost-effectiveness ratio of $372,853.

CONCLUSION

For patients with small (6- to 9-mm) polyps detected at CTC screening, the exclusion of large polyps (> or = 10 mm) already confers a very low risk of CRC. The high costs, additional complications, and relatively low incremental yield associated with immediate polypectomy of 6- to 9-mm polyps support the practice of 3-year CTC surveillance, which allows for selective noninvasive identification of small polyps at risk.

A simplified, noninvasive stool DNA test for colorectal cancer detection

BACKGROUND

As a noninvasive colorectal cancer (CRC) screening test, a multi-marker first generation stool DNA (sDNA V 1.0) test is superior to guaiac-based fecal occult blood tests. An improved sDNA assay (version 2), utilizing only two markers, hypermethylated vimentin gene (hV) and a two site DNA integrity assay (DY), demonstrated in a training set (phase 1a) an even higher sensitivity (88%) for CRC with a specificity of 82%.

AIM

To validate in an independent set of patients (phase 1b) the sensitivity and specificity of sDNA version 2 for CRC.

METHODS

Forty-two patients with CRC and 241 subjects with normal colonoscopy (NC) provided stool samples, to which they immediately added DNA stabilizing buffer, and mailed their specimen to the laboratory. DNA was purified using gel-based capture, and analyzed for hV and DY using methods identical to those previously published.

RESULTS

Using the same cutpoints as the 1a training set (N = 162; 40 CRCs, 122 normals), hV demonstrated a higher and DY a slightly lower sensitivity, for a combined sensitivity of hV + DY of 86%. Optimal cutpoints based on the combined phase 1a + 1b dataset (N = 445; 82 CRCs, 363 normals) yielded a CRC sensitivity of 83%. The vast majority of cancers were detected regardless of tumor stage, tumor location, or patient age. Assay specificity in the phase 1b dataset for hV, DY, and hV + DY was 82%, 85%, and 73%, respectively, using the phase 1a cutpoints. Optimal cutpoints based on the combined phase 1a + 1b dataset yield a specificity of 82%.

CONCLUSIONS

This study provides validation of a simplified, improved sDNA test that incorporates only two markers and that demonstrates high sensitivity (83%) and specificity (82%) for CRC. Test performance is highly reproducible in a large set of patients. The use of only two markers will make the test easier to perform, reduce the cost, and facilitate distribution to local laboratories.

Stool DNA and occult blood testing for screen detection of colorectal neoplasia

BACKGROUND

Stool DNA testing is a new approach to colorectal cancer detection. Few data are available from the screening setting.

OBJECTIVE

To compare stool DNA and fecal blood testing for detection of screen-relevant neoplasia (curable-stage cancer, high-grade dysplasia, or adenomas >1 cm).

DESIGN

Blinded, multicenter, cross-sectional study.

SETTING

Communities surrounding 22 participating academic and regional health care systems in the United States.

PARTICIPANTS

4482 average-risk adults.

MEASUREMENTS

Fecal blood and DNA markers. Participants collected 3 stools, smeared fecal blood test cards and used same-day shipment to a central facility. Fecal blood cards (Hemoccult and HemoccultSensa, Beckman Coulter, Fullerton, California) were tested on 3 stools and DNA assays on 1 stool per patient. Stool DNA test 1 (SDT-1) was a precommercial 23-marker assay, and a novel test (SDT-2) targeted 3 broadly informative markers. The criterion standard was colonoscopy.

RESULTS

Sensitivity for screen-relevant neoplasms was 20% by SDT-1, 11% by Hemoccult (P = 0.020), 21% by HemoccultSensa (P = 0.80); sensitivity for cancer plus high-grade dysplasia did not differ among tests. Specificity was 96% by SDT-1, compared with 98% by Hemoccult (P < 0.001) and 97% by HemoccultSensa (P = 0.20). Stool DNA test 2 detected 46% of screen-relevant neoplasms, compared with 16% by Hemoccult (P < 0.001) and 24% by HemoccultSensa (P < 0.001). Stool DNA test 2 detected 46% of adenomas 1 cm or larger, compared with 10% by Hemoccult (P < 0.001) and 17% by HemoccultSensa (P < 0.001). Among colonoscopically normal patients, the positivity rate was 16% with SDT-2, compared with 4% with Hemoccult (P = 0.010) and 5% with HemoccultSensa (P = 0.030).

LIMITATIONS

Stool DNA test 2 was not performed on all subsets of patients without screen-relevant neoplasms. Stools were collected without preservative, which reduced detection of some DNA markers.

CONCLUSION

Stool DNA test 1 provides no improvement over HemoccultSensa for detection of screen-relevant neoplasms. Stool DNA test 2 detects significantly more neoplasms than does Hemoccult or HemoccultSensa, but with more positive results in colonoscopically normal patients. Higher sensitivity of SDT-2 was particularly apparent for adenomas.

College of Radiology, Academy of Medicine of Malaysia position on whole body screening CT scans in healthy asymptomatic individuals (2008)

To date, the College of Radiology (CoR) does not see any clear benefit in performing whole body screening computed tomography (CT) examinations in healthy asymptomatic individuals. There are radiation risk issues in CT and principles of screening should be adhered to. There may be a role for targeted cardiac screening CT that derives calcium score, especially for asymptomatic medium-risk individuals and CT colonography when used as part of a strategic programme for colorectal cancer screening in those 50 years and older. However, population based screening CT examinations may become appropriate when evidence emerges regarding a clear benefit for the patient outweighing the associated radiation risks.

Risk of developing proximal versus distal colorectal cancer after a negative colonoscopy: a population-based study

BACKGROUND & AIMS

The incidence of colorectal cancer (CRC) overall is reduced for up to 10 years after a negative colonoscopy. The objective of this research was to determine the incidence of proximal and distal CRC after a negative complete colonoscopy.

METHODS

A cohort of Ontario residents aged 50 to 80 years who had a negative complete colonoscopy between January 1, 1992, and December 31, 1997, was identified by using linked administrative databases. Cohort members had no prior history of CRC, inflammatory bowel disease, or recent colonic resection. Each individual was followed up through December 31, 2005, and the relative rate (RR) of overall CRC, distal CRC, and proximal CRC was compared with the remaining Ontario population.

RESULTS

A cohort of 110,402 individuals with a negative complete colonoscopy was identified. The RR of CRC overall and the RR of distal CRC remained significantly lower than the Ontario population. For example, at year 14 the RR of distal CRC was 0.21 (95% confidence interval, 0.05-0.36). The RR of proximal CRC was significantly lower than the Ontario population in half of the follow-up years, mainly after 7 years of follow-up.

CONCLUSIONS

Over a 14-year follow-up period, negative complete colonoscopy was associated with a subsequent reduced incidence of CRC overall, and of incident CRC in the distal colon. However, the reduction in incidence of proximal CRC differed in magnitude and timing, and occurred in half the follow-up years, mainly after 7 years of follow-up. These results highlight an important limitation of colonoscopy in usual clinical practice.

Polyp size and advanced histology in patients undergoing colonoscopy screening: implications for CT colonography

BACKGROUND & AIMS

Colorectal cancer screening with diagnostic imaging can detect polyps. The management of patients whose largest polyp is less than 10 mm is uncertain. The primary aim of this study was to determine rates of advanced histology in patients undergoing colorectal cancer screening whose largest polyp is 9 mm or less.

METHODS

Subjects include all asymptomatic adults receiving colonoscopy for screening during 2005 from 17 practice sites, which provide both colonoscopy and pathology reports to the Clinical Outcomes Research Initiative repository. Patients were classified by size of largest polyp. Advanced histology was defined as an adenoma with villous or serrated histology, high-grade dysplasia, or an invasive cancer. Risk factors for advanced histology were determined using Pearson chi(2) and Fisher exact tests.

RESULTS

Among 13,992 asymptomatic patients who had screening colonoscopy, 6360 patients (45%) had polyps, with complete histology available in 5977 (94%) patients. The proportion with advanced histology was 1.7% in the 1- to 5-mm group, 6.6% in the 6- to 9-mm group, 30.6% in the greater than 10-mm group, and 72.1% in the tumor group. Distal location was associated with advanced histology in the 6- to 9-mm group (P = .04) and in the greater than 10-mm group (P = .002).

CONCLUSIONS

One in 15 asymptomatic patients whose largest polyp is 6 to 9 mm will have advanced histology and would undergo surveillance at 3 years based on current guidelines. Because histology is necessary for this decision, most of these patients should be offered colonoscopy. Further study should determine whether patients whose largest polyp is 1-5 mm can be safely followed without polypectomy.

Epigenetic regulation of WNT signaling pathway genes in inflammatory bowel disease (IBD) associated neoplasia

INTRODUCTION

WNT signaling pathway dysregulation is an important event in the pathogenesis of colorectal cancer (CRC) with APC mutations seen in more than 80% of sporadic CRC. However, such mutations in the WNT signaling pathway genes are rare in inflammatory bowel disease (IBD) associated neoplasia (dysplasia and cancer). This study examined the role of epigenetic silencing of WNT signaling pathway genes in the pathogenesis of IBD-associated neoplasia.

METHODS

Paraffin-embedded tissue samples were obtained and methylation of ten WNT signaling pathway genes, including APC1A, APC2, SFRP1, SFRP2, SFRP4, SFRP5, DKK1, DKK3, WIF1 and LKB1, was analyzed. Methylation analysis was performed on 41 IBD samples, 27 normal colon samples (NCs), and 24 sporadic CRC samples.

RESULTS

Methylation of WNT signaling pathway genes is a frequent and early event in IBD and IBD-associated neoplasia. A progressive increase in the percentage of methylated genes in the WNT signaling pathway from NCs (4.2%) to IBD colitis (39.7%) to IBD-associated neoplasia (63.4%) was seen (NCs vs. IBD colitis, p < 0.01; IBD colitis vs. IBD-associated neoplasia, p = 0.01). In the univariate logistic regression model, methylation of APC2 (OR 4.7, 95% CI: 1.1-20.63, p = 0.04), SFRP1 (OR 5.1, 95% CI: 1.1-31.9, p = 0.04), and SFRP2 (OR 5.1, 95% CI: 1.1-32.3, p = 0.04) was associated with progression from IBD colitis to IBD-associated neoplasia, while APC1A methylation was borderline significant (OR 4.1, 95% CI: 0.95-17.5, p = 0.06). In the multivariate logistic regression model, methylation of APC1A and APC2 was more likely to be associated with IBD-associated neoplasia than IBD colitis. (OR APC1A: 6.4, 95% CI: 1.1-37.7 p = 0.04; OR APC2 9.1, 95% CI: 1.3-61.7, p = 0.02).

SUMMARY

Methylation of the WNT signaling genes is an early event seen in patients with IBD colitis and there is a progressive increase in methylation of the WNT signaling genes during development of IBD-associated neoplasia. Moreover, methylation of APC1A, APC2, SFRP1, and SFRP2 appears to mark progression from IBD colitis to IBD-associated neoplasia, and these genes may serve as biomarkers for IBD-associated neoplasia.

A provider intervention to improve colorectal cancer screening in county health centers

BACKGROUND

Publicly-funded health centers serve disadvantaged populations who underuse colorectal cancer screening (CRC). Because physicians play a key role in patient adherence to screening, provider interventions within health center practices could improve the delivery/utilization of CRC screening.

METHODS

A 2-group study design was used with 4 pairs of health centers randomized to the intervention or control condition. The provider intervention featured academic detailing of the small practice groups, followed by a strategic planning session with the entire health center staff using SWOT analysis. The outcome measure of provider endoscopy referral/fecal occult blood test dispensing and/or completion of CRC screening was determined by medical record audit (n = 2224). The intervention effect was evaluated using generalized estimating equations. Pre-post intervention patient surveys (n = 281) were conducted.

RESULTS

Chart audits of the 1 year period before and after the intervention revealed a 16% increase from baseline in CRC screening referral/dispensing/completion among intervention centers, compared with a 4% increase among controls, odds ratio (OR) = 2.25 (1.67-3.04) P < 0.001. Intervention versus control health center patient self-reports of lack of physician recommendation as a reason for not having CRC screening declined from baseline to follow-up (P = 0.04).

CONCLUSIONS

Provider referrals/dispensing/completion of CRC screening within health centers was significantly improved and barriers reduced through a provider intervention combining continuing medical education with a team building strategic planning exercise.

Prevalence of colon polyps detected by colonoscopy screening in asymptomatic black and white patients

CONTEXT

Compared with white individuals, black men and women have a higher incidence and mortality from colorectal cancer and may develop cancer at a younger age. Colorectal cancer screening might be less effective in black individuals, if there are racial differences in the age-adjusted prevalence and location of cancer precursor lesions.

OBJECTIVES

To determine and compare the prevalence rates and location of polyps sized more than 9 mm in diameter in asymptomatic black and white individuals who received colonoscopy screening.

DESIGN, SETTING, AND PATIENTS

Colonoscopy data were prospectively collected from 67 adult gastrointestinal practice sites in the United States using a computerized endoscopic report generator between January 1, 2004, and December 31, 2005. Data were transmitted to a central data repository, where all asymptomatic white (n = 80 061) and black (n = 5464) patients who had received screening colonoscopy were identified.

MAIN OUTCOME MEASURES

Prevalence and location of polyps sized more than 9 mm, adjusted for age, sex, and family history of colorectal cancer in a multivariate analysis.

RESULTS

Both black men and women had a higher prevalence of polyps sized more than 9 mm in diameter compared with white men and women (422 [7.7%] vs 4964 [6.2%]; P < .001). Compared with white patients, the adjusted odds ratio (OR) for black men was 1.16 (95% confidence interval [CI], 1.01-1.34) and the adjusted OR for black women was 1.62 (95% CI, 1.39-1.89). Black and white patients had a similar risk of proximal polyps sized more than 9 mm (OR, 1.13;95% CI, 0.93-1.38). However, in a subanalysis of patients older than 60 years, proximal polyps sized more than 9 mm were more likely prevalent in black men (P = .03) and women (P < .001) compared with white men and women.

CONCLUSION

Compared with white individuals, black men and women undergoing screening colonoscopy have a higher risk of polyps sized more than 9 mm, and black individuals older than 60 years are more likely to have proximal polyps sized more than 9 mm.

Construct validity and invariance of four factors associated with colorectal cancer screening across gender, race, and prior screening

Understanding individuals' perceptions of colorectal cancer screening (CRCS) is important for developing effective interventions to increase adherence to screening guidelines. Theory-based cognitive and psychosocial constructs have been associated with CRCS in the literature, but few studies have evaluated the psychometric properties of such measures. We hypothesized a correlated four-factor model, including CRCS perceived pros, cons, social influence, and self-efficacy. We also examined measurement invariance across subgroups based on gender, race (white; African American), and prior CRCS experience (never; overdue for repeat screening). We used baseline (n = 1,250) and 2-week (n = 1,036) follow-up survey data from participants in a behavioral intervention trial designed to increase CRCS. Only minor modifications were made to the hypothesized model to improve fit, and the final model was confirmed with a random half of the sample, as well as with follow-up data. Results support the hypothesized unidimensional construct measures and suggest that the items may be appropriate for all subgroups examined. Greater variance in responses to items assessing the perceived cons of CRCS was found among African Americans compared with whites, suggesting that race may moderate the association between perceived cons and CRCS in this sample. Pros, cons, social influence, and self-efficacy are associated with CRCS; therefore, using scales with known psychometric properties strengthens researchers' ability to draw conclusions about group differences and changes over time and to compare their results with other studies. Replication studies in other populations are needed to provide further evidence of construct validity for the scales reported here.

The aging of the HIV epidemic

Since the advent of highly active antiretroviral therapy, life expectancies for persons with HIV infection are similar to those for uninfected people. A growing proportion of HIV-infected individuals are now over the age of 50. We are also seeing an increase in the incidence of HIV infection in older adults. To meet the challenges of the ongoing HIV epidemic, prevention efforts should include a focus on older adults. Also, HIV care providers must address the many comorbidities that are common in the aging population. Additional research will clarify how the processes of aging and HIV infection overlap and interact. This review addresses many of these important considerations.

Computed tomography colonography (virtual colonoscopy): climax of a new era of validation and transition into community practice

Colorectal cancer, which kills more than 50,000 patients every year in the United States and costs more than $6 billion in direct health costs, is a prime target for cancer prevention. Computed tomography colonography (CTC) has emerged as a minimally invasive, structural examination of the entire colon that can complement the current tools of cancer prevention and may improve patient compliance. Large trials have suggested a sensitivity of roughly 90% and specificity greater than 97% for CTC for patients with polyps >or= 10 mm. Bowel preparation by diet restriction, catharsis, and stool and fluid tagging are typically used. A prepless CTC protocol is an active area of research with a focus on improving patient compliance. Insurance coverage of CTC is a key factor affecting current dissemination and local and national coverage decisions are ongoing. CT examination of the abdomen allows visualization of extracolonic organs, where detection of additional disease must balance any unnecessary anxiety and testing. Estimates of CTC cost-effectiveness are generally favorable, but vary due to the high sensitivity of these models to costs, polyp sensitivity, compliance rates, and other parameters, which are difficult to accurately assess. Quality initiatives are being developed that will be key for implementation into community practice.