Using the so-called MISCAN-Colon model (microsimulation screening analysis), a cohort of 10 million 50-year-olds was simulated, to which 588 different screening strategies were applied, created by varying the following parameters: screening interval (1, 2 or 3 years), FIT cut-off (faecal immunochemical test up to 15, 20, 47 or 60 µg haemoglobin/g stool), age at which colonoscopy begins (5 0, 52, 54, 55, 56, 58 or 60 years) and the age at which colonoscopy is stopped (70, 72, 74, 75, 76, 78 or 80 years).1
As these are not clinical data, the study focused primarily on which screening approach is most cost-effective. The best strategy proved to be annual screening from the age of 50 to 80 using faecal immunochemical tests (FIT) with a cut-off value of 15 µg/g. Due to the increasing life expectancy, the higher cancer risk in older people and the overall low burden of FIT screening, screening over-75s could be more cost-effective than lowering the starting age for screening.2 raises the question of the extent to which screening beyond the age of 75 would be feasible in terms of colonoscopy capacity, since FIT screening in older people has higher positive rates, leading to an increased demand for colonoscopies.
When should colonoscopies for early detection be stopped?
The results show that further research is needed to determine for which older individuals a favourable risk-benefit ratio exists, the authors of the analysis conclude. In this context, the invasiveness of the examination and the individual state of health should be taken into account, which in turn actually only makes a personalised decision seem sensible.
A gastroenterologist not involved in the evaluation, Dr S. Kusuma Pokala from the University of Colorado, commented: ‘Screening concepts for colorectal cancer in older people should be further investigated, as the population of people over 75 years of age is increasing and the benefits and harms of continuing screening are unclear."2
Clinical data will certainly be crucial to the question of when a patient is “too old” for routine colonoscopies. In a large study during surveillance colonoscopies after polypectomy in older people, cancer was rarely detected. The detection rate for carcinomas did not increase with age, suggesting that there is an age beyond which the risks of colonoscopy outweigh the benefits.3
Conclusion for medical practice
The analysis authors conclude that the discussion about the age for colorectal cancer screening should not focus solely on lowering the age of onset. ‘Further studies should focus on the risks and benefits of continuing screening at an older age and on identifying individuals for whom the risks outweigh the benefits.’1
The value of colonoscopy for early cancer detection had not been investigated in a randomised form until the ‘NordICC’ (Northern European Initiative on Colorectal Cancer) study.4 This gold standard study, published in 2022 in the ‘New England Journal of Medicine’, with a 10-year follow-up period and 84,000 participants, came to that colonoscopy screening reduces CRC risk by about one fifth and does not significantly reduce mortality.5
Since then, several randomised controlled trials have been launched to evaluate colonoscopy, some of them in comparison with alternative screening methods such as faecal immunochemical tests (FIT).4 A final verdict on colonoscopy that can be applied to clinical practice is therefore likely to be some time in coming.
- van de Schootbrugge-Vandermeer, H. J., Toes-Zoutendijk, E., de Jonge, L., van leerdam, M. E. & Lansdorp-Vogelaar, I. When to Start, When to Stop With Colorectal Cancer Screening: A Cost-Effectiveness Analysis. Gastroenterology 167, 801-803.e5 (2024).
- When to Start, When to Stop With Colorectal Cancer Screening. PracticeUpdate https://www.practiceupdate.com/content/when-to-start-when-to-stop-with-colorectal-cancer-screening/165905.
- Lee, J. K. et al. Surveillance Colonoscopy Findings in Older Adults With a History of Colorectal Adenomas. JAMA Network Open 7, e244611 (2024).
- Powell, K. & Prasad, V. Interpreting the results from the first randomised controlled trial of colonoscopy: does it save lives? BMJ Evidence-Based Medicine 28, 306–308 (2023).
- Bretthauer, M. et al. Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death. New England Journal of Medicine 387, 1547–1556 (2022). Letzter Zugriff auf Websites: 17.10.24.