Evaluation of the Colorectal Cancer Screening Program for the 2013–2014 Period: National Indicators
This subsection presents follow-up data on individuals who underwent a screening test (guaiac test: Hemoccult® II) between January 1, 2013, and December 31, 2014.
A description of the indicators is available in the Data Format Guide and Definitions of Indicators for the Evaluation of the National Program
Quality of Screening Tests and Examinations
This section presents follow-up data for individuals who underwent a screening test (guaiac test: Hemoccult® II) between January 1, 2013, and December 31, 2014. Based on these data, quality indicators for screening tests and diagnostic examinations are produced, including the rate of individuals with at least one unanalyzed test, the rate of individuals with an unanalyzed test that was not retested, the rate of positive tests, the percentage of colonoscopies performed…
The national quality indicators for screening tests and diagnostic examinations are shown in the table opposite: xls format and pdf format
Test Performance Quality
In total, 4.7 million people underwent a screening test during these two years. Among them, 278,289 (5.9%) had a test that turned out to be non-analysable. The proportion of people with an unanalyzable test was similar among men (6.0%) and women (5.9%). This proportion was higher for a first screening than for a subsequent screening among men (8.0% vs. 5.3%) as well as among women (7.8% vs. 5.3%).
The main reasons for unanalyzable tests were: expired sample (23.9%), failure to identify the sample (20.5%), and excessive fecal matter (12.5%).
Breakdown of reasons for non-analysis of tests
Percentage of people who underwent a colonoscopy following a positive test
Among the 102,379 people with a positive test, 89,380 underwent a colonoscopy, representing a colonoscopy uptake rate of 88.6%, which is higher than the acceptable European benchmark (85%) and close to the desirable benchmark (90%)1. This rate varied by department, ranging from 51.3% in French Guiana to 96.8% in Mayenne (Table in xls and pdf formats). Eighteen (23%) departments had rates below the acceptable European benchmark of 85%, and 48% had rates equal to or above the desirable European benchmark of 90%.
Quality of the colonoscopy
The quality of preparation for the colonoscopies performed was rated as good for 81.8%, average for 6.1%, and insufficient for 2.0% of the exams. Information on the quality of the colonoscopy was missing for 10% of the exams.
Distribution of colonoscopies performed by preparation quality
A colonoscopy is considered incomplete when the entire colon and rectum are not examined during the procedure. Among those who underwent a colonoscopy, the percentage of individuals who had a complete colonoscopy was 93.4% for both men and women. This figure is slightly higher than the acceptable benchmark recommended at the European level (90%) and lower than the desirable benchmark (95%). The reasons why colonoscopies were incomplete varied by sex: 36.0% of cases were due to anatomical reasons among men versus 43.0% among women; 30.5% among men were due to obstructive lesions versus 26.4% among women. Other reasons included inadequate preparation (12.3% in men vs. 13.9% in women) or another unspecified reason (21.3% vs. 16.7%).
Breakdown of incomplete colonoscopies by reason
1 Segnan N, Patnick J, von Karsa L (eds). European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition. Luxembourg: European Commission, 2010.
Follow-up of examinations
This subsection presents follow-up indicators for examinations (coloscopy-related morbidity, time to coloscopy, and the percentage of lost-to-follow-up cases) for individuals who participated in the program between January 1, 2013, and December 31, 2014.
Colonoscopy morbidity
Information on colonoscopy complications, particularly deaths occurring in the days following the procedure, is incomplete, as for 50.9% of colonoscopies, the variable recording incidents and adverse events associated with this diagnostic procedure was not reported. It is therefore impossible to determine whether the information is missing or whether the colonoscopy proceeded without complications. Given these limitations, the statistics on colonoscopy morbidity cannot be used as is.
Timelines for performing colonoscopies
The distribution of wait times for colonoscopies following a positive test shows that only 24.2% of colonoscopies were performed within the timeframe consistent with the European benchmark (i.e., 1 month). The median wait time was 62 days (xls format and pdf format). It varied by department. The shortest median wait times (<50 days) were observed in the departments of Alpes-Maritimes, Ille-et-Vilaine, and Pyrénées-Orientales, and the longest (over 3 months) in the departments of Martinique and Vienne (xls format and pdf format).
Geographic distribution of the percentages of lost-to-follow-up cases
A person is considered lost to follow-up when the managing agency is unable to obtain any information about that person 24 months after the positive test result. The percentage of "lost to follow-up" cases was 7.6% (8.2% among men and 6.9% among women). This percentage ranged from 0% in the Ardennes to 47.7% in French Guiana (XLS format and PDF format). These departmental disparities reflect the heterogeneity in the quality of data collection regarding the follow-up of individuals who tested positive (for example, the transmission of information by healthcare professionals to the management structure is more or less systematic).
Detected lesions
Presented here are the indicators of lesions detected in individuals who participated in the program between January 1, 2013, and December 31, 2014. These indicators relate to the nature and rates of lesions detected (adenomas, advanced adenomas, and cancers) through diagnostic examinations (colonoscopy or other).
Over this period, the program detected approximately 20,900 advanced neoplastic lesions (15,267 advanced adenomas and 5,635 colorectal cancers).
The detection rate for advanced adenomas (and colorectal cancers, respectively) is defined as the proportion of patients in whom an advanced adenoma (or cancer, respectively) is the most serious lesion detected, among those who underwent an analyzable screening test. It is expressed per 1,000 screened individuals.
The detection rate for advanced adenomas (adenomas 10 mm or larger, or presenting high-grade dysplasia, or a villous component) was 3.3 per 1,000 screened individuals (xls format and pdf format). It was higher among men (4.6 per 1,000) than among women (2.1 per 1,000), increased with age, and was higher during the first screening than during subsequent screenings.
Distribution of the detection rate of advanced adenomas by age, sex, and screening round (adenoma 10 mm or larger, or with high-grade dysplasia, or a villous component)
The detection rate of advanced adenomas varied by department: among men, it ranged from 1.2 per 1,000 in Martinique to 13.8 per 1,000 in the Calvados department, and among women from 0.7 per 1,000 in the Alpes-de-Haute-Provence department to 5.7 per 1,000 in Calvados (xls format and pdf format).
Detection rate of advanced adenomas for men
Detection rate of advanced adenomas for women
The cancer detection rate was 1.2 per 1,000 people screened. It varied by age, sex, and screening round. Among women, it was 1.0 per 1,000 during the first screening and 0.8 per 1,000 during subsequent screenings, whereas among men, it was 1.9 per 1,000 and 0.8 per 1,000, respectively—nearly twice as high (xls format and pdf format). It also varied by department: among men, it ranged from 0.7 per 1,000 in the departments of Lozère and Pyrénées-Orientales to 3.3 per 1,000 in the department of Calvados, and among women from 0.3 per 1,000 in the departments of Eure-et-Loir and Vaucluse (xls format and pdf format).
Colorectal cancer detection rates for men
Colorectal cancer detection rates for women
Departmental detection rates for advanced adenomas and colorectal cancers depend heavily on the departmental incidence of cancer and the performance of departmental programs (ability to detect these lesions). The percentage of eligible individuals who undergo a colonoscopy following a positive test and the percentage of those lost to follow-up are factors that influence the recording of these lesions and may help explain departmental disparities. Furthermore, the lack of reproducibility in the diagnosis of advanced adenoma also contributes to explaining the observed departmental differences in advanced adenoma rates[1].
[1] Denis, B., Bottlaender, J., Breysacher, G., Chiappa, P., Peter, A., Weiss, A.-M. The advanced adenoma: A topical concept but an out-of-date definition? (2011) Hepato-Gastro, 18 (3), pp. 269-276.
Stages of detected cancers
The stage of cancers detected by the organized screening program was determined according to the international TNM classification of malignant tumors[1]. This classification system allows cancers to be classified according to their degree of anatomical spread: size of the primary tumor (or T), lymph node involvement (or N), and presence of metastasis (or M), and applies, for the colon and rectum, only to adenocarcinomas. For colon and rectal cancers, the pTNM anatomopathological classification was adopted. For rectal cancers, which may undergo neoadjuvant treatments prior to surgery—resulting in changes to the T and N stages of the detected tumor—the quality of available data and the heterogeneity of methods for documenting staging information do not allow for the determination of the TNM stage prior to treatment. Consequently, only colon cancers (including the rectosigmoid junction) and rectal cancers that did not receive neoadjuvant therapy were included.
The cancer stage is considered unknown when at least one of the pT, pN, or M values is unknown (unless pT=Tis, in which case the pTNM stage is in situ, or if M=M1, in which case the pTNM stage is IV). Among the detected adenocarcinomas of the rectum (without neoadjuvant therapy) and colon, this information was missing in 27.6% of patients. When the stage could not be determined, T was missing in 14.8% of cases, N was missing in 17.3% of cases, and M was missing in 27.0% of cases. This percentage of adenocarcinomas of unknown stage reflects significant regional variation: it ranged from 0% to 100% (xls format and pdf format), as information on the metastatic status of detected cancers is difficult to access.
The description covers only the 52 departments with less than 30% missing data on cancer stages, corresponding to 2,957 detected colorectal adenocarcinomas (without neoadjuvant treatments). Among these adenocarcinomas, 8.0% are of unknown pTNM stage.
Among adenocarcinomas with known stages, 24.4% were carcinomas in situ and 75.6% were invasive cancers (stages I to IV), of which 37.7% were stage I, 24.7% stage II, 24.9% stage III, and 12.7% stage IV (xls format and pdf format).
