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 are encouraged to undergo colorectal cancer screening every two years. Participation rates, calculated for the 2017–2018 period for all French departments, are presented here, along with exclusion rates and positivity rates.

Materials and Methods

The method for calculating the indicators is based on the data format guide and definitions of indicators for the national program evaluation (see Data Format Guide). The indicators are thus calculated over a two-year period, during which the entire eligible population of a department is invited to participate in screening.

Test used for screening

Reminder: The guaiac fecal occult blood test (Hemoccult® II) was replaced by the immunological test (OC Sensor®) in April 2015.

Calculation of the participation rate

The participation rate is the ratio of the number of people screened to the eligible population, i.e., the program’s target population (men and women aged 50 to 74) from which individuals excluded from the program for medical reasons are subtracted.

The number of people screened—that is, the number of men and women aged 50 to 74 who underwent a screening test during the evaluation period (here, from January 1, 2017, to December 31, 2018)—and the average number of people excluded from the program for medical reasons are provided by the administrative bodies. The definition of medical exclusions is specified in the specifications (see above).

The eligible population is obtained by calculating the arithmetic mean of the target population (based on the estimated number of people aged 50–74 for the calendar years 2017 and 2018 derived from INSEE projections for 2007–2042, central scenario), from which the average number of people aged 50–74 excluded from the program for medical reasons during the two calendar years (2017 and 2018) must be subtracted.

Calculation of the exclusion rate

The exclusion rate is the ratio of the number of people excluded (temporarily or permanently) from the organized colorectal cancer screening program to the program’s target population (see above).

The number of excluded individuals is provided by the administrative bodies based on various usable data sources (responses from invited individuals, records of colonoscopies reimbursed by the primary health insurance funds, records of diagnostic and therapeutic procedures, standardized reports of colonoscopy results and anatomopathological examinations, etc.), but access to which varies by administrative unit.

Calculation of the positivity rate

The positivity rate is the ratio of the number of people with a positive screening test to the number of people with an analyzable test, that is, a test that could be read by the laboratory.

Age groups

Data are presented by five-year age group.

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 the invitation; the 70–74 age group includes individuals who had turned 75 at the time of screening, to account for the time it takes to complete the test for those invited at age 74.

Standardization of indicators

Participation, exclusion, and positivity rates are calculated by department, by region, and for France as a whole. They are standardized by age and sex using the 2009 French population as the reference 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 different geographic units (departments or regions), for comparing results across these areas and analyzing trends over time for the various indicators studied.

European standards

European standards recommend a participation rate of the target population of 45% or higher.

Results

Participation

Over the 2017–2018 period, the population eligible for the program is estimated at 19.7 million people aged 50 to 74. Nearly 5.5 million underwent an immunological screening test, representing a participation rate of 32.1% (see tables in PDF and Excel formats).

The participation rate is higher among women (33.4%) than among men (30.7%) (see tables in PDF and Excel formats), regardless of age group (see tables in PDF and Excel formats). It increases with age (from 29.7% to 37.9% among men and from 31.2% to 38.4% among women).

There is a regional disparity in participation rates (see Map 1, Map 2, and tables in PDF and Excel formats). Rates are particularly low (<25%) in the departments of Ardèche, Corsica, French Guiana, Paris, Réunion, Ariège, Gard, Hérault, Lozère, and Alpes-Maritimes. The highest rates are found in Saône-et-Loire (45.1%), Maine-et-Loire (45.3%), and Ille-et-Vilaine (46.5%).

Exclusion

Medical exclusions must be reported regularly and as comprehensively as possible to ensure the quality of the program. They may be either permanent for medical reasons (personal or family history of adenomas or colorectal cancer, familial adenomatous polyposis, chronic inflammatory bowel disease, non-polyposis hereditary colorectal cancer, or Lynch syndrome), or temporary due to symptoms or because a colonoscopy with normal results was performed within the past five years.

Over the 2017–2018 period, the exclusion rate was 13.3%, corresponding to 2.6 million people (see tables in PDF and Excel formats). This exclusion rate is identical for men and women. It increases with age, rising among men from 6.2% for those aged 50–54 to 23.5% for those aged 70–74, and among women from 7.0% for the youngest to 20.4% for the oldest (see tables in PDF and Excel formats). This rate also varies by department, ranging from 1.9% in Bouches-du-Rhône to 23.7% in Bas-Rhin (see Map 3 and tables in PDF and Excel formats).

Positive tests

Note: The positivity threshold used is 30 µg of human hemoglobin per gram of stool (or 150 ng/ml of buffer), corresponding to an expected positivity rate in the French population of approximately 4%.

In total, over the 2017–2018 period, the screening test result was positive for 213,000 people, representing a positivity rate of 4.0%. This rate is higher among men (4.9%) than among women (3.2%) and increases with age (from 3.9% to 6.4% among men and from 2.8% to 4.1% among women; tables in PDF and Excel formats). It also varies by department, ranging from 3.3% to 4.7% (map and tables in PDF and Excel formats).

Conclusion

Between 2017 and 2018, 5.5 million people aged 50 to 74 underwent a screening test, representing a participation rate of 32.1%. The expected increase in participation following the switch to the immunological test has therefore not materialized so far. The participation rate remains well below the minimum acceptable European target of 45%. The rate of people with a positive immunological test result (4.0%) is in line with expectations.