Colorectal cancer screening in primary care

Predictive Levels of CD24 in Peripheral Blood Leukocytes for the Early Detection of Colorectal Adenomas and Adenocarcinomas

CD24 is expressed in 90% of colorectal adenomas and adenocarcinomas. Colorectal cancer (CRC) can be mostly prevented but average risk population screening by stool testing or colonoscopy faces many hurdles. Blood testing is clinically needed. We aimed to evaluate the utility of CD24 expression in peripheral blood leukocytes (PBLs). Two independent case studies were conducted in eligible individuals undergoing colonoscopy. Protein extracted from PBLs was subjected to immunoblotting using anti-CD24 monoclonal antibodies. CD24 sensitivity and specificity were determined using receiver operating characteristic (ROC) analysis. Initially, 150 subjects were examined: 63 had CRC, 19 had adenomas, and 68 had normal colonoscopies. The sensitivity and specificity of CD24 for distinguishing CRC from normal subjects were 70.5% (95% CI, 54.8–83.2%) and 83.8% (95% CI, 74.6–92.7%) and for adenomas 84.2% (95% CI, 60.4–96.4%) and 73.5% (95% CI, 61.4–83.5%), respectively. In the second trial (n = 149), a similar specificity but higher sensitivity was achieved: 80.0% (95% CI, 63.1–91.6%) for CRC and 89.2% (95% CI, 74.6–97%) for adenomas. A simple noninvasive blood test evaluating CD24 levels has high sensitivity and specificity for detecting colorectal adenomas and cancer in patients undergoing colonoscopy at an urban medical center. Larger multicenter studies are warranted to establish the potential of this promising test.

Factors associated with adherence to fecal occult blood testing for colorectal cancer screening among adults in the Republic of Korea

PURPOSE

Repeated participation in fecal occult blood testing (FOBT) is one of the major factors affecting the long-term success of population-based colorectal cancer screening programs. The aim of this study is to explore strong factors linked to repeated participation in FOBT in the prior decade (2002-2011) among adults using the Health Belief Model (HBM) after controlling for other covariates.

METHODS

Data were obtained from South Korean adults, aged 50 years and over, who visited a national health screening center within a magnet hospital (N = 237). A pilot test was conducted to investigate the internal consistency of the HBM instruments and the clarity of survey questions. Sample characteristics and rates of adherence to FOBT screening were examined using means and frequencies. Important factors associated with adherence to FOBT were examined using multivariate logistic regression analysis.

RESULTS

About 44% of the respondents were adherent to FOBT screening over the prior decade. Four out of the six HBM-driven factors (perceived susceptibility, severity, and barriers, and health motivation) were statistically significant. Those with greater levels of susceptibility and health motivation and lower levels of severity and barriers were more likely to adhere to FOBT.

CONCLUSIONS

Health professionals should focus more on the four modifiable HBM-related factors to encourage adults to adhere to FOBT. Intervention programs, which lower perceived severity and barriers and increase susceptibility and health motivation, should be developed and implemented.

Colorectal cancer screening in evolution: Japan and the USA

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

Participation in colorectal cancer screening with FOBT and colonoscopy: an Italian, multicentre, randomized population study

BACKGROUND

Data on the adherence rate to screening colonoscopy (OC) in the average-risk general population are limited and variable. Aim of this study was to compare the uptake of OC screening with that of fecal occult blood (FOBT).

METHODS

A nationwide, population-based, multicentre, randomized trial comparing attendance to OC with that to FOBT was performed. Sixty-four general practitioners (GPs), overall including in their lists 9889 average-risk subjects aged 55-64 years, were randomized between OC and FOBT screening programs. Eligible subjects were mailed a personal invitation letter co-signed by their GP and the coordinator of the area-reference GI centre. Attendance rate and detection rate for advanced neoplasia (colorectal cancer, adenoma >10mm or with villous histology or high-grade dysplasia) for each arm of the study were assessed.

RESULTS

The overall attendance rate was 18.7% (1563/8378 eligible subjects). It was markedly lower in the OC than in the FOBT strategy (10% vs. 27.1%; OR 0.28, 95% CI: 0.25-0.32; P<0.0001). In particular, participation in OC screening arm was extremely low in South Italy (2.8%), whilst it was higher in North-Central Italy (12.4%; P<0.0001). Compliance to colonoscopy in those with a positive FOBT was only 58%. Advanced neoplasia was detected in 28 (6.8%) patients in the OC arm and in 6 (18%) in those with a positive FOBT submitted to OC.

CONCLUSIONS

The results of our study underline the difficulties and barriers to implement a OC population screening in Italy, at least through primary care. Although attendance to FOBT was higher, it was disappointingly less than 30%. Significant actions to improve awareness amongst GPs and the population are a high priority.

Random comparison of guaiac and immunochemical fecal occult blood tests for colorectal cancer in a screening population

BACKGROUND & AIMS

Despite poor performance, guaiac-based fecal occult blood tests (G-FOBT) are most frequently implemented for colorectal cancer screening. Immunochemical fecal occult blood tests (I-FOBT) are claimed to perform better, without randomized comparison in screening populations. Our aim was to randomly compare G-FOBT with I-FOBT in a screening population.

METHODS

We conducted a population-based study on a random sample of 20,623 individuals 50-75 years of age, randomized to either G-FOBT (Hemoccult-II) or I-FOBT (OC-Sensor). Tests and invitations were sent together. For I-FOBT, the standard cutoff of 100 ng/ml was used. Positive FOBTs were verified with colonoscopy. Advanced adenomas were defined as >or=10 mm, high-grade dysplasia, or >or=20% villous component.

RESULTS

There were 10,993 tests returned: 4836 (46.9%) G-FOBTs and 6157 (59.6%) I-FOBTs. The participation rate difference was 12.7% (P < .01). Of G-FOBTs, 117 (2.4%) were positive versus 339 (5.5%) of I-FOBTs. The positivity rate difference was 3.1% (P < .01). Cancer and advanced adenomas were found, respectively, in 11 and 48 of G-FOBTs and in 24 and 121 of I-FOBTs. Differences in positive predictive value for cancer and advanced adenomas and cancer were, respectively, 2.1% (P = .4) and -3.6% (P = .5). Differences in specificities favor G-FOBT and were, respectively, 2.3% (P < .01) and -1.3% (P < .01). Differences in intention-to-screen detection rates favor I-FOBT and were, respectively, 0.1% (P < .05) and 0.9% (P < .01).

CONCLUSIONS

The number-to-scope to find 1 cancer was comparable between the tests. However, participation and detection rates for advanced adenomas and cancer were significantly higher for I-FOBT. G-FOBT significantly underestimates the prevalence of advanced adenomas and cancer in the screening population compared with I-FOBT.