Following a pilot phase in 23 metropolitan departments, organized colorectal cancer screening was expanded nationwide starting in 2008. Since 2010, this program has covered all French departments, with the exception of Mayotte (which became a French department on March 31, 2011). Screening is coordinated at the local level by departmental or interdepartmental management structures (a total of 89 management structures). Participation rates, calculated for the years 2011 and 2012 for all French departments, are presented in this document, along with exclusion rates and the percentages of positive tests.

Materials and Methods

The specifications for cancer screening programs published in the Official Journal on December 21, 2006 (Appendix to No. 295) stipulate that individuals aged 50 to 74 must be invited to undergo colorectal cancer screening every two years. The indicators are thus calculated over a two-year period, during which the entire population of a department is invited to participate in screening.

Calculation of the participation rate

The participation rate is the ratio of the number of people screened to the target screening population (men and women aged 50 to 74), from which individuals excluded from screening for medical reasons are subtracted. It is defined as:

The number of people screened—that is, men and women aged 50 to 74 who underwent a screening test during the evaluation period (here, from January 1, 2011, to December 31, 2012)—and the number of people excluded from screening are provided by the administrative bodies via a standardized annual questionnaire.

At the national level and for the purpose of comparing departments, the denominators used to calculate participation rates are population data provided by INSEE (2007–2042 projections, central scenario), calculated identically across the entire country. From this population, individuals who are temporarily or permanently excluded from screening for medical reasons are subtracted. The definition of medical exclusions is specified in the specifications (see above).

Calculation of the exclusion rate

The exclusion rate is the ratio of the number of people temporarily or permanently excluded from the organized colorectal cancer screening program (see above) to the INSEE target population for screening (men and women aged 50 to 74).

The number of excluded individuals is provided by the administrative bodies via a standardized annual questionnaire.

Calculation of the percentage of positive tests

This is the ratio of the number of people with a positive test result to the number of people with a test result that can be analyzed by the screening test reading centers.

This information is provided by the administrative units via a standardized annual questionnaire.

Age groups

A breakdown into 5-year age groups was used.

The 50–54 age group includes individuals who turned 50 during the year under review, even if they had not yet reached that age at the time of screening; the 70–74 age group includes individuals who had turned 75 at the time of screening, generally due to a delay in taking the test after receiving the invitation sent up to age 74.

Standardization of indicators

Participation rates, exclusion rates, and the percentage of positive tests are calculated by department, by region, and for France. They are standardized by age and sex relative to the 2009 French population (INSEE projection 2007–2042, central scenario). This standardization allows, by applying the same age and sex structure (that of the 2009 French population) to geographic units, for comparing results between these units (departments or regions) and for studying changes over time in the various indicators examined.

Benchmarks

The European benchmark recommends a participation rate of the target population of at least 45% for the screening program to be cost-effective. This benchmark applies to all European countries that have implemented an organized screening program.

Results

Participation

Over the 2011–2012 period, the population of people aged 50 to 74 is estimated at 17.9 million individuals. Nearly 5 million people underwent a screening test, representing a national participation rate of 31.7% (see table). Participation is stable compared to the rate for the 2010–2011 period (32.1%). It falls short of the minimum acceptable European target of 45% participation, far below the desirable rate of 65%.

Participation is higher among women (33.7%) than among men (29.6%), regardless of age group (see table). It is observed that people over 60 participate in the program more than younger individuals, for both men and women. This trend persisted from the 2009–2010 period through 2011–2012 (see graph).

Among men, those aged 55 to 59 participate the least in screening. Starting at age 60, men’s participation increases with age, reaching its peak (35.9%) in the 70–74 age group (see table). During the 2009–2010 and 2010–2011 periods, the same age-related variations in participation were observed for men (see graph). Participation by age differs among women: while the lowest participation is also observed among the youngest women (less than 30.5% participation for women under 60), it is highest for the 65–69 age group (38.3%). Over the 2009–2010 period, the highest participation rate was observed for the 60–64 age group, but it is for this age group that participation appears to have declined most sharply between 2009–2010 and 2011–2012 (see graph).

Participation in organized screening varies by region and department: see maps and tables (PDF and Excel formats). The highest rate is recorded in Alsace (44.1%) and the lowest in Corsica (7.1%). Compared to the 2010–2011 period, participation has increased in six regions (Alsace, Centre, Franche-Comté, Guadeloupe, Réunion, and Pays-de-Loire), with the largest increase observed in Guadeloupe, where participation rose from 25.1% to 27.5%. Conversely, Burgundy is the region where participation has declined the most sharply, with this decline being particularly pronounced among individuals under 60 years of age. Only two departments—Haut-Rhin, with 47.1%, and Saône-et-Loire, with 51.4% participation—exceeded the recommended minimum threshold of 45% participation for the 2011–2012 period. It is worth noting that, for 11 departments, the participation rate ranged between 40% and 45%. It should also be noted that participation rates in 38 departments increased between 2010–2011 and 2011–2012, with a rise of more than four percentage points in the Loiret and Seine-et-Marne. Thirty-three departments have rates below 30%.

Findings regarding screening participation by age at the national level show some regional disparities (see table). In Corsica, there is no difference in participation before and after age 60, for either men or women, with participation remaining stable across the different age groups. In Alsace, Burgundy, and French Guiana, the lowest participation rate for men is among those aged 50–54. In Upper Normandy, Languedoc-Roussillon, and Martinique, men aged 70–74 participate less than those aged 65–69. In Réunion, men aged 60–64 participate most in screening. Among women, in Auvergne, Guadeloupe, Limousin, PACA, and Picardy, the highest participation rate is observed for the 70–74 age group, whereas in Champagne-Ardenne, Franche-Comté, and Réunion, it is highest for the 60–64 age group. It is also noted that participation among women over 65 in Réunion is lower than that of younger women. Participation rates by region, sex, and age for the periods 2009–2010, 2010–2011, and 2011–2012 are presented here. During the 2009–2010 period, four departments (Corsica, Indre, Nièvre, and French Guiana) were not included in the assessment due to a lack of prior screening data. The rates for the corresponding regions (including France) are therefore not directly comparable between the two periods.

Exclusions

The percentage of people excluded from this program (permanent exclusions for medical reasons or temporary exclusions following normal colonoscopy results) is 11.8%. It is similar among men (11.6%) and women (11.9%) and increases with age. It is higher among women than men for individuals under 65, but the trend reverses for those over 65 (see table). The exclusion rate varies by department from 3.3% to 18.1% (see maps and table). It remains very low in the overseas departments and Corsica, although there was a slight increase in the exclusion rate between the 2010–2011 and 2011–2012 periods for these departments. The variation in exclusion rates across departments is certainly due, in part, to the fact that, for departments with a longer history in the program, there are more temporary or permanent exclusions resulting from screening-induced colonoscopy findings than for those just beginning organized colorectal cancer screening. It also depends on the efficiency of data collection regarding medical exclusions by the administrative bodies.

Positive tests

The percentage of positive tests is 2.4%, or 116,160 positive tests. It is higher among men (2.8%) than among women (2.1%), and it increases with age (see table). There is significant variability in the rate of positive tests across departments, ranging from 1.2% in Martinique to 6.0% in French Guiana: see maps and table. Overall, the positive test rate decreased from 2.6% to 2.4% between the 2010–2011 and 2011–2012 periods, with this trend observed in 76% of departments. This decrease is particularly significant in Allier (-44%) and Cher (-30%), which used immunological tests as part of pilot programs during the 2010–2011 period. The decrease in the rate of positive tests is consistent with the repeated screening campaigns, which make it possible to identify and thus exclude from the target screening population individuals with precancerous or cancerous lesions in the colon and rectum; these individuals are then subject to specific follow-up by their physician.

Conclusion

The organized colorectal cancer screening program is now well established throughout France, but participation rates remain low, particularly among people under 60. The program’s protocols are expected to change soon, as the Directorate General of Health has approved the replacement of guaiac tests (Hemoccult®) with new immunological tests using antibodies directed against human blood proteins. These immunological tests have higher sensitivity than the guaiac test for detecting cancers and, in particular, advanced adenomas. The superior performance of the immunological test is likely to increase general practitioners’ confidence and their adherence to the program, which is known to be a key factor in population participation. Furthermore, this change in testing method could have a positive impact on screening participation due to greater public acceptance of this test, as its sample collection technique limits contact with stool compared to the guaiac test. The transition to the immunological test is scheduled for 2014.