Fecal Occult Blood Tests for Colorectal Cancer Screening in Routine Medical Care

A longitudinal analysis from Germany

Background: Well-organized programs for colorectal cancer (CRC) screening with fecal occult blood testing (FOBT) can reach over 70% of the eligible population. FOBT was opportunistic in Germany up to 2019. Until March 2025, it was offered annually to persons aged 50 to 54 and twice per year to persons aged 55 and above. Cross-sectional analyses revealed only moderate annual adherence rates, but it remained unclear whether the tests were used regularly by a small share of the population or sporadically by a large share of the population.

Methods: We used anonymized data from BARMER, a German statutory health insurance carrier, to study trends in adherence to annual FOBT screening among persons aged 50 to 54 over the years 2010–2022. The data pertained to 945 214 men and women who were born in the period 1960–1968.

Results: Despite the offer of annual screening, only 22.5% of men and 55.1% of women had at least one FOBT between the ages of 50 and 54. Only 0.1% of men and 1.8% of women used the screening annually as offered. The use of screening has declined even further in recent years. CRC was found in 1.4% of follow-up colonoscopies in both men and women.

Conclusion: The opportunistic mode of offering annual FOBT for CRC screening in Germany is highly ineffective, as most of the eligible population did not have even a single test from age 50 to age 54.

Cite this as: Klimeck L, Heisser T, Hennig B, Graf C, Hoffmeister M, Brenner H: Fecal occult blood tests for colorectal cancer screening in routine medical care: A longitudinal analysis from Germany. Dtsch Arztebl Int 2025; 122: 455–60. DOI: 10.3238/arztebl.m2025.0102

With more than 1.9 million new cases every year, colorectal cancer poses a major health problem worldwide (1). The health burden is especially prominent in highly developed western nations such as Germany, where colorectal cancer is the second leading cause of cancer mortality, accounting for more than 24 000 deaths each year (2). Fecal occult blood tests (FOBT) are among the globally most commonly offered methods for colorectal cancer screening. Moreover, FOBT-based screening is cost efficient and can reduce the incidence and mortality of colorectal cancer by 20–32% (3, 4, 5, 6). Modern fecal immunochemical tests (FIT) have replaced guaiac-based tests (gFOBT) because they are more user-friendly and possess significantly better diagnostic accuracy in detecting colorectal cancer (7, 8).

In Germany, adults with statutory health insurance (approximately 90% of the population) are eligible for a fecal test for the purpose of colorectal cancer screening from age 50 years. From 2002 to March 2025, the service offered annual FOBT for persons aged 50–54 years and biennial FOBT from age 55 onwards (Table 1). Since April 2025, testing has been offered biennially starting at the age of 50 years. Persons with a positive test require diagnostic colonoscopy. In 2017, the gFOBT previously used in Germany were replaced by FIT. Beginning in 2002, up to two screening colonoscopies 10 years apart were offered as an alternative screening option. The starting age for screening colonoscopy was lowered to age 50 in 2019 for men and in 2025 for women.

Table 1

Colorectal cancer screening options in Germany between 2002 and March 2025

Rates of participation in FOBT-based screening have remained low in most countries without organized colorectal cancer screening programs, although there are exceptions such as Luxembourg (9). By contrast, well-organized FOBT-based screening programs for colorectal cancer can reach utilization rates of more than 70% of the eligible population (9, 10). In Germany, FOBT have predominantly been offered opportunistically, i.e., without any organized invitation and follow-up procedures. Eligible persons must actively collect the fecal test from a physician’s office, return it after use, and make an additional visit to receive the results. Only in 2019 were the first steps taken towards an organized program: information leaflets and invitations were sent to persons aged 50, 55, 60, and 65 years urging them to consult their primary care physician about colorectal cancer screening (11). Nevertheless, cross-sectional analyses have revealed very low rates of FOBT utilization in Germany (12, 13). It is unclear whether tests were used regularly by a small proportion of the population or sporadically by a large proportion of the population (14).

In this study, routine statutory health insurance data were used to analyze the longitudinal uptake of colorectal cancer screening by means of FOBT in Germany. Attention was focused on the age group 50–54 years, as the alternative of screening by means of colonoscopy was not offered to women of this age at all during the observation period and was not introduced for men until 2019.

Methods

Study design

This study is based on anonymized data from the statutory health insurance carrier BARMER, which maintains a data warehouse for the purpose of healthcare research. The data warehouse contains information on all persons insured by BARMER in Germany from 2005 onwards. In our study we assessed the longitudinal use of FOBT use at the age of 50–54 years by one-year birth cohorts from the years 1960– 1968. Persons with a previous diagnosis of colorectal cancer (ICD-10 codes C18–C21) or inflammatory bowel disease (ICD-10 codes K50–51), previous colonoscopy within the past 10 years, less than 5 years of BARMER insurance, or any gaps in insurance were excluded.

During the observation period, all prescriptions, diagnoses, and medical procedures of insured persons were recorded in the database. As all the birth cohorts included in analysis had been offered annual FOBT screening at the age of 50–54 years, all persons had ad the opportunity of performing up to five annual fecal tests during the observation period. On the basis of the insurance data, we were able to calculate how often, when, and at what age the eligible cohorts took advantage of the annual FOBT screening offer.

The use of FOBT and diagnostic colonoscopy use was determined by means of the Uniform Assessment Standard code (Einheitlicher Bewertungsmaßstab, EBM) and the Operation and Procedure codes (Operationen- und Prozedurenschlüssel, OPS), which are used by physicians in Germany for billing purposes (EBM 01734 for gFOBT, 01737 or 01738 for FIT) (15). Persons who received the test kit but left it unused did not fall under the aforementioned EBM codes. We furthermore investigated whether a diagnostic colonoscopy (EBM 13421/13422, OPS 1–650) was performed within 6 months after the date of each test, which would indicate a positive test result. The data did not allow assessment of the number of persons who tested positive but did not take up the offer of a colonoscopy for diagnostic clarification.

Statistical analysis

Several measures of uptake were calculated. The cross-sectional utilization rate among the eligible population was calculated as the number of persons who used the fecal test in a given year divided by the number of persons eligible in that year. The longitudinal utilization rate among the eligible population was quantified using the following metrics:

• Number and proportion of the persons in a birth cohort who used the fecal test at least one, two, three, four or five times at the age of 50–54 years
• Average number of fecal tests at the age of 50–54 years among the FOBT users in each birth cohort

In addition, the number and proportion of diagnostic colonoscopies and polypectomies within 6 months of an FOBT and the number and proportion of subsequent colorectal cancer diagnoses were calculated. The vast majority of colorectal cancer diagnoses occurred within the same quarter as the diagnostic colonoscopy. However, colorectal cancer diagnoses within 6 months of diagnostic colonoscopy were also included so as account for any delays in diagnosis and billing. In view of the major differences in utilization rates between men and women, all analyses were stratified by sex.

Results

A total of 945 214 persons (41% male, 59% female) were identified who were eligible for annual FOBT-based colorectal cancer screening at the age of 50–54 years between 2010 and 2022 (eFigure 1). The average cross-sectional annual utilization rates are presented in Figure 1. The rates were 27.8% for women and 7.6% for men in 2010 and showed a slight but steady decrease between 2010 and 2015, a slight but steady increase between 2015 and 2018, and then a decrease to less than 21% for women and less than 6% for men in the period 2020–2022.

Figure 1

Cross-sectional utilization rates of fecal tests between 2010 and 2022

eFigure 1

Flow chart of study sample

The longitudinal rates of fecal test utilization between 50 and 54 years of age, stratified by sex, are shown in Table 2. Overall, 22.9% of men and 55.5% of women made use of a fecal test at least once in 5 years, and 0.1% of men and 1.8% of women used five consecutive fecal tests. On average, women used a fecal test 2.1 times within 5 years, men 1.4 times. A diagnostic colonoscopy was conducted within 6 months after 3.5% of fecal tests (men: 5%, women: 3.2%), and colorectal cancer was diagnosed within 6 months after 1.4% of diagnostic colonoscopies (men: 1.4%, women: 1.4%). Of the 27 676 diagnostic colonoscopies, 52.3%,27.2%, 13.9%, 5.5%, and 1.1%, were conducted after a 1^st, 2^nd, 3^rd, 4^th, and 5^th FOBT, respectively (eTable 1). Stratification of the analyses by single-year birth cohort shows very little variation (eTables 2–3).

Table 2

Metrics of longitudinal utilization of annual fecal occult blood tests at ages 50–54 years together with frequency and results of follow-up diagnostic colonoscopies

eTable 1

Proportion of diagnostic colonoscopies after each test

eTable 2

Metrics of longitudinal utilization of annual fecal occult blood tests at ages 50–54 years by birth cohort together with frequency and results of follow-up diagnostic colonoscopies: men

eTable 3

Metrics of longitudinal utilization of annual fecal occult blood tests offered at ages 50–54 by birth cohort together with frequency and results of follow-up diagnostic colonoscopies: women

The average cumulative rates of fecal test use by sex and by the number of tests used in relation to the eligible general population are presented in Figure 2. Across all cohorts, 22.9% of all eligible men used at least one test and 6.5% at least two tests, while 0.1% used all five tests at yearly intervals. In women, the observed utilization rates were much higher: 55.5% of women used at least one test, 33.9% at least two tests, and 1.8% used all five tests. Analyses stratified by type of fecal test showed little variation in uptake between gFOBT and FIT (eFigures 2–4).

Figure 2

Average cumulative rates of utilization of at least one, two, three, four, or all five fecal tests, expressed in absolute numbers of tests used and as percentage of the eligible population in parentheses, by sex and across all birth cohorts

eFigure 2

Average cumulative utilization rates of at least one, two, three, four, or all five fecal tests, expressed in absolute case numbers and in as percentage of the eligible population in parentheses, by sex and across all birth cohorts with access to gFOBT only (birth cohorts 1960–1962)

eFigure 3

Average cumulative utilization rates of at least one, two, three, four, or all five fecal tests, expressed in absolute case numbers and in as percentage of the eligible population in parentheses, by sex and across all birth cohorts with access to gFOBT in earlier years and FIT in later years (birth cohorts 1963–1967)

eFigure 4

Average cumulative utilization rates of at least one, two, three, four, or all five fecal tests, expressed in absolute case numbers and in as percentage of the eligible population in parentheses, by sex and across all birth cohorts with access to FIT only (birth cohort 1968)

Figure 3 shows the proportion of the eligible population that used no fecal test-based colorectal cancer screening between the ages of 50 and 55 years. The vast majority of eligible men (96.4%) and women (85.3%) remained untested at the age of 51 years, and 77.1% of eligible men and 44.5% of all eligible women had still not used a test to screen for colorectal cancer by the time they reached the age of 55 years.

Figure 3

Percentage of the untested population by age and sex across all cohorts

Discussion

In this study, we assessed longitudinal adherence patterns of fecal test-based colorectal cancer screening from 2010 to 2022 using health insurance data from Germany. Of a group of more than 945 000 eligible persons, 42.2% used a fecal test at least once between 50 and 54 years of age. Only around 1% had taken full advantage of the annual testing offered to those in this age group. In addition, our study revealed distinct disparities between the sexes. Overall, 77.1% of men and 44.5% of women had undergone no fecal test for colorectal cancer screening by the age of 55 years.

The cross-sectional utilization rates and the large variation by sex are in line with previously reported national utilization rates from 2009 to 2018 in Germany (12). Longitudinal utilization rates have not previously been published for Germany, but have been reported for other countries (16, 17, 18, 19). In an organized colorectal cancer screening program introduced in the Netherlands in 2014, eligible individuals are biennially sent an invitation kit containing information on colorectal cancer, a FIT sampling device, and instructions for use (20). If no fecal sample is received, a reminder is sent. The pilot program for the Dutch organized screening program was conducted between 2006 and 2014 and revealed that about 70% of invited participants used at least one fecal test, with 50% responding to the invitations to all four rounds of tests (10). Furthermore, the introduction of the organized screening program translated into a significant reduction in colorectal cancer incidence in the Netherlands (21). Similar to the Netherlands, the Bowel Cancer Screening Programme in England also mails the fecal test kits to the eligible population. Between 2006 and 2012, using gFOBT, the English program achieved a 70% rate of utilization of at least one test, with 44% of persons responding to all invitations over the course of three biennial screening rounds (17).

The results of our study are not directly comparable with those from the Netherlands and England, given the differences in age range (50–74 years and 60–74 years in the studies from the Netherlands and England, respectively) and screening interval (2 years in the Netherlands and England, annual screening offers at age 50–54 years in Germany). Nevertheless, the far higher utilization rates the Netherlands and England highlight the benefit of a well-organized screening program and underline the urgency for action in Germany. That the implementation of core elements of the programs from the Netherlands and England can also dramatically increase utilization rates in Germany was demonstrated in a randomized trial by our study group, in which direct mailing of fecal test kits to persons aged 50–54 years with health insurance from the carrier AOK in the federal state of Baden–Württemberg approximately tripled the prevailing utilization rates (22).

The opportunistic nature of the colorectal cancer screening program in Germany also largely explains the exceptionally wide disparity in utilization rates of fecal tests between men and women. The reasons for this gender gap include less frequent visits to primary care physicians and specialists by men, differences in risk perception, and other social norms (23, 24). In particular, women in Germany are often given fecal test kits for colorectal cancer screening during routine visits to gynecologists. For example, over half of all FOBT performed in 2018 were prescribed by gynecological offices (12). The much lower and overall very low rates of utilization of FOBT by men is concerning, particularly because age-specific colorectal cancer risks are much higher in men (25). Although the alternative offer of a screening colonoscopy from the age of 50 years, introduced in 2019, may have influenced men’s utilization of fecal test-based colorectal cancer screening, this effect was probably minimal given the consistent difference between the sexes observed over the entire observation period from 2010 to 2022.

Limitations

A potential limitation of our study is the extent to which the data are representative of the overall German population. The proportions of women and older persons among those with health insurance provided by BARMER are slightly higher than in the German general population. However, most of our analyses were conducted in an age- and sex-stratified manner, so their results should not be affected by disparities in sex and age distribution. Further, the similarity of the cross-sectional rates of FOBT use observed in our study to previously reported national cross-sectional rates (12), along with results from previous analyses of risk selection across different public insurance funds in Germany (26), suggests that the results can be viewed as largely representative.

Conclusion

This study assessed longitudinal utilization rates of fecal test-based colorectal cancer screening at the age of 50–54 years in Germany, using routine data from the BARMER health insurance carrier. The rate of use of at least one test between the ages of 50 and 54 years was low: 22.9% for men and 55.5% for women. Only 0.1% of men and 1.8% of women used a fecal test every year. Despite the offer of a test each year between the ages of 50 and 54 years, 44.5% of women and 77.1% of men remained unscreened at the end of the 5-year period. Moreover, neither the switch from gFOBT- to FIT-based screening nor the introduction of an invitation letter at age 50 years led to increased utilization.

In summary, the current implementation of colorectal cancer screening in an essentially opportunistic manner in Germany is associated with very low utilization rates. Much higher participation rates might be achieved by introducing core elements of well-organized screening programs, e.g., direct mailing of invitation letters, provision of easy-to-understand information materials, and the sending of test kits (27), as is done in the Netherlands and England. The implementation of improved, cost-efficient programs should be pursued with priority given the strongly increasing number of colorectal cancer otherwise anticipated, due especially to demographic changes (28) and the increasing age-specific incidence in younger generations (29).

Funding

Financial support for this study was provided by the German Federal Ministry of Education and Research (grant number 01KD2104A-E). The funding agreement ensured the authors’ independence in designing the study, interpreting the data, writing the manuscript, and publishing the results.

Ethics approval

This study was approved by the ethics committee of the Heidelberg Medical Faculty of Heidelberg University (S-511/2024).

Conflict of interest statement

The authors declare that no conflict of interest exists.

Manuscript received on 20 December 2024, revised version accepted on 30 May 2025

Corresponding author:
Prof. Dr. Hermann Brenner

References

1. Bray F, Laversanne M, Sung H, et al.: Global cancer statistics 2022: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin 2024;74: 229–63

2. Robert Koch-Institut: Krebs in Deutschland für 2019/2020. 2023. www.krebsdaten.de/Krebs/DE/Content/Publikationen/Krebs_in_Deutschland/krebs_in_deutschland_node.html (last accessed on 26 September 2024).

3. Mandel JS, Church TR, Bond JH, et al.: The effect of fecal occult-blood screening on the incidence of colorectal cancer. N Engl J Med 2000; 343: 1603–7

4. Hewitson P, Glasziou P, Watson E, Towler B, Irwig L: Cochrane systematic review of colorectal cancer screening using the fecal occult blood test (hemoccult): An update. Am J Gastroenterol 2008; 103: 1541–9

5. Shaukat A, Mongin SJ, Geisser MS, et al.: Long-term mortality after screening for colorectal cancer. N Engl J Med 2013; 369: 1106–14

6. Senore C, Hassan C, Regge D, et al.: Cost-effectiveness of colorectal cancer screening programmes using sigmoidoscopy and immunochemical faecal occult blood test. J Med Screen. 2019; 26: 76–83

7. Brenner H, Tao S: Superior diagnostic performance of faecal immunochemical tests for haemoglobin in a head-to-head comparison with guaiac based faecal occult blood test among 2235 participants of screening colonoscopy. Eur J Cancer 2013; 49: 3049–54

8. Tinmouth J, Lansdorp-Vogelaar I, Allison JE: Faecal immunochemical tests versus guaiac faecal occult blood tests:What clinicians and colorectal cancer screening programme organisers need to know. Gut 2015; 64: 1327–37

9. Ola I, Cardoso R, Hoffmeister M, Brenner H: Utilization of colorectal cancer screening tests across European countries: A cross-sectional analysis of the European health interview survey 2018–2020. Lancet Reg Health Eur 2024; 41: 100920

10. van der Vlugt M, Grobbee EJ, Bossuyt PM, et al.: Adherence to colorectal cancer screening: Four rounds of faecal immunochemical test-based screening. Br J Cancer 2017; 116: 44–9

11. Gemeinsamer Bundesausschuss: Richtlinie für organisierte Krebsfrüherkennungsprogramme. 2018. www.g-ba.de/richtlinien/104/ (last accessed on 26 September 2024).

12. Steffen A, Holstiege J, Hagen B, Akmatov MK, Bätzing J: Inanspruchnahme der Darmkrebsfrüherkennung in den Jahren 2009 bis 2018: Eine Bestandsaufnahme auf Basis bundesweiter vertragsärztlicher Abrechnungsdaten. Zentralinstitut für die kassenärztliche Versorgung in Deutschland. 2020. www.versorgungsatlas.de/themen/alle-analysen-nach-datum-sortiert/108/bericht (last accessed on 27 September 2024).

13. Prutz F, Rommel A, Thom J, Du Y, Sarganas G, Starker A: Utilisation of outpatient medical services in Germany—results from GEDA 2019/2020-EHIS. J Health Monit 2021; 6: 45–65.

14. Heisser T, Cardoso R, Guo F, Moellers T, Hoffmeister M, Brenner H: Strongly divergent impact of adherence patterns on efficacy of colorectal cancer screening: The need to refine adherence statistics. Clin Transl Gastroenterol 2021; 12: e00399

15. Kassenärztliche Bundesvereinigung: Einheitlicher Bewertungsmaßstab (EBM). 2022. https://www.kbv.de/media/sp/EBM_Gesamt_-_Stand_1._Quartal_2022.pdf (last accessed on 26 September 2024).

16. Kapidzic A, Grobbee EJ, Hol L, et al.: Attendance and yield over three rounds of population-based fecal immunochemical test screening. Am J Gastroenterol 2014; 109: 1257–64

17. Lo SH, Halloran S, Snowball J, Seaman H, Wardle J, von Wagner C: Colorectal cancer screening uptake over three biennial invitation rounds in the English bowel cancer screening programme. Gut 2015; 64: 282–91

18. Klabunde C, Blom J, Bulliard JL, et al.: Participation rates for organized colorectal cancer screening programmes: An international comparison. J Med Screen 2015; 22: 119–26

19. Doubeni CA, Fedewa SA, Levin TR, et al.: Modifiable failures in the colorectal cancer screening process and their association with risk of death. Gastroenterology 2019; 156: 63–74 e6

20. National Institute for Public Health and the Environment: Overview of programme structure—Dutch colorectal cancer screening programme. 2020. www.rivm.nl/en/media/167891 (last accessed on 26 September 2024).

21. Breekveldt ECH, Lansdorp-Vogelaar I, Toes-Zoutendijk E, et al.: Colorectal cancer incidence, mortality, tumour characteristics, and treatment before and after introduction of the faecal immunochemical testing-based screening programme in the Netherlands: A population-based study. Lancet Gastroenterol Hepatol 2022; 7: 60–8

22. Gruner LF, Hoffmeister M, Ludwig L, Meny S, Brenner H: The effects of differing invitation models on the uptake of immunological fecal occult blood testing. Dtsch Arztebl Int 2020; 117: 423–30

23. Clarke N, Sharp L, Osborne A, Kearney PM: Comparison of uptake of colorectal cancer screening based on fecal immunochemical testing (FIT) in males and females: A systematic review and meta-analysis. Cancer Epidemiol Biomarkers Prev 2015; 24: 39–47

24. Teo CH, Ng CJ, Booth A, White A: Barriers and facilitators to health screening in men: A systematic review. Soc Sci Med 2016; 165: 168–76

25. Chen X, Heisser T, Cardoso R, Hoffmeister M, Brenner H: Personalized initial screening age for colorectal cancer in individuals at average risk. JAMA Netw Open 2023; 6: e2339670

26. Nuscheler R, Knaus T: Risk selection in the German public health insurance system. Health Econ 2005; 14: 1253–71

27. Peterse EFP, Osoro CB, Bardou M, Lansdorp-Vogelaar I: Comparative benefit and cost-effectiveness of mailed-out faecal immunochemical tests vs collection at the general practitioner. Aliment Pharmacol Ther 2021; 53: 1118–25

28. Heisser T, Hoffmeister M, Tillmanns H, Brenner H: Impact of demographic changes and screening colonoscopy on long-term projection of incident colorectal cancer cases in Germany: A modelling study. Lancet Reg Health Eur 2022; 20: 100451

29. Tanaka LF, Figueroa SH, Popova V, Klug SJ, Buttmann-Schweiger N: The rising incidence of early-onset colorectal cancer. Dtsch Arztebl Int 2023; 120: 59–64