Background: The guaiac faecal occult blood test (G-FOBT) is recommended as a screening test for colorectal cancer but its low sensitivity has prevented its use throughout the world. Methods: We compared the performances of the reference G-FOBT (non-rehydrated Hemoccult II test) and the immunochemical faecal occult blood test (I-FOBT) using different positivity cut-off values in an average risk population sample of 10 673 patients who completed the two tests. Patients with at least one test positive were asked to undergo colonoscopy. Results: Using the usual cut-off point of 20 ng/ml haemoglobin, the gain in sensitivity associated with the use of I-FOBT (50% increase for cancer and 256% increase for high risk adenoma) was balanced by a decrease in specificity. The number of extra false positive results associated with the detection of one extra advanced neoplasia (cancer or high risk adenoma) was 2.17 (95% confidence interval 1.65–2.85). With a threshold of 50 ng/ml, I-FOBT detected more than twice as many advanced neoplasias as the G-FOBT (ratio of sensitivity = 2.33) without any loss in specificity (ratio of false positive rate = 0.99). With a threshold of 75 ng/ml, associated with a similar positivity rate to G-FOBT (2.4%), the use of I-FOBT allowed a gain in sensitivity of 90% and a decrease in the false positive rate of 33% for advanced neoplasia. Conclusions: Evidence in favour of the substitution of G-FOBT by I-FOBT is increasing, the gain being more important for high risk adenomas than for cancers. The automated reading technology allows choice of the positivity rate associated with an ideal balance between sensitivity and specificity.

In aggregate studies, ecological indices are used to study the influence of socioeconomic status on health. Their main limitation is ecological bias. This study assesses the misclassification of individual socioeconomic status in seven ecological indices. Individual socioeconomic data for a random sample of 10,000 persons came from periodic health examinations conducted in 2006 in 11 French departments. Geographical data came from the 2007 census at the lowest geographical level available in France. The Receiver Operating Characteristics (ROC) curves, the areas under the curves (AUC) for each individual variable, and the distribution of deprived and non-deprived persons in quintiles of each aggregate score were analyzed. The aggregate indices studied are quite good “proxies” for individual deprivation (AUC close to 0.7), and they have similar performance. The indices are more efficient at measuring individual income than education or occupational category and are suitable for measuring of deprivation but not affluence. The study inventoried the aggregate indices available in France and evaluated their assessment of individual SES.

The struggle against social inequalities is a priority for many international organizations. The objective of the study was to quantify the cancer burden related to social deprivation by identifying the cancer sites linked to socioeconomic status and measuring the proportion of cases associated with social deprivation.

Socio-economic, environmental factors and general practitioner (GP) involvement may influence adherence to repeat faecal occult blood testing (FOBT) of organised colorectal cancer (CRC) screening. The aim of the study was to identify predictors of adherence to repeat testing. The populationcomprised people eligible for the third round of a CRC screening programme in a French district (n=118,905). Multilevel logistic regression analysis was performed to identify individual and area-level characteristics associated with 'compliant participants' participating in the all three rounds vs 'occasional participants' participating in one or two rounds. Compared to 'occasional participants', 'compliant participants' were more likely to participate after receiving a FOBT kit from their GP (odds ratio (OR), 10.7; 95% CI, 10.01-11.5) vs FOBT received at home, and were less likely to live in socio-economically deprived areas (OR, 0.75; 0.70-0.80) and urban areas (OR, 0.94; 0.88-1.00). As for a screening round participation, strategies aimed at improving the participation to a screening programme should target GPs and people living in socially deprived areas.