Following a pilot phase in 23 metropolitan departments, organized colorectal cancer screening was rolled out 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 2010 and 2011 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 people 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.

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 those excluded from screening 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, 2010, to December 31, 2011)—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 reported by the administrative units 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.

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 45% or higher. This benchmark applies to all European countries that have implemented an organized screening program.

Results

Over the 2010–2011 period, 17 million people aged 50 to 74 were invited to undergo screening, and 5 million of them participated in the program.

The national screening participation rate for this period was 32.1%.

This rate is below the minimum acceptable European target of 45% participation and far below the desirable rate of 65%.

Participation is higher among women (34.0%) than among men (30.0%), regardless of the age group considered. It is also noted that people over 60 participate in the program more than younger individuals: see graph and here.

Participation in organized screening varies by region and department: see maps and table (PDF format and Excel format).

The highest regional rate is recorded in Burgundy (47.5%) and the lowest in Corsica (8.3%). Participation is on the rise in Midi-Pyrénées and the North compared to the 2009–2010 period. Only five departments (Cher, Côte-d’Or, Haut-Rhin, Isère, Saône-et-Loire) meet or exceed the recommended threshold of 45% participation for the years 2010 and 2011. The highest rates are observed in Côte-d’Or and Saône-et-Loire (over 50% participation). Thirty-three departments have rates below 30%. It is worth noting that participation rates in 23 departments increased between 2009–2010 and 2010–2011, notably with a 67% increase in Haute-Garonne, where participation rose from 17.0% to 28.4%.

The percentage of people excluded from this program (permanent exclusions for medical reasons or temporary exclusions following normal colonoscopy results) varies by department from 2.4% to nearly 17.5%: see maps and table, which likely reflects significant disparities in the collection of data on these exclusions across departments. The lowest exclusion rates are observed primarily among departments that joined the screening program late and overseas departments. The exclusion rate for the 23 pilot departments already participating prior to 2008 is 12.8%, higher than the exclusion rate for the other departments (10.6%). This difference may be due, in part, to the fact that, for departments with a longer history in the program, temporary or permanent exclusions resulting from screening-induced colonoscopy findings are more numerous than for those just beginning organized colorectal cancer screening.

The percentage of positive tests for France is 2.6% among analyzable tests, or 126,332 positive tests: see table. It is higher among men (3.0%) than among women (2.0%). The two departments with the highest rates are French Guiana (4.8%) and Eure (4.0%), while Pyrénées-Atlantiques and Martinique have the lowest rates of positive tests (1.7%). It is noted that the positive test rate is lower in the pilot departments (2.4%) than in the other departments (2.7%) (excluding departments that used immunological tests as part of trials during the 2010–2011 period: Allier, Calvados, Cher). These results suggest a decrease in the prevalence of precancerous or cancerous lesions in departments that have been involved in screening for several years.

Conclusion

This program now allows the entire French population to benefit from organized screening to combat colorectal cancer. In 2011, the InVS evaluated the program for 46 departments over the 2008–2009 period. In these 46 departments, the program detected an advanced adenoma in 14,125 people and cancer in 5,412 people.

New immunological tests using antibodies directed against proteins in human blood are now available. In December 2008, the French National Authority for Health (HAS) recommended initiating the process of replacing guaiac tests (Hemoccult®) with immunological tests within the organized screening program. The summary published by the National Cancer Institute (INCa) last November regarding the transition to the use of immunological screening tests confirms the value of these new tests in colorectal cancer screening for the detection of precancerous lesions and early-stage cancers. Furthermore, these tests are likely to be better accepted by the public due to simplified collection procedures, which could have a positive impact on participation in the program.