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Review Population-based screening colonoscopy in Korea: balancing benefits and limitations
Hyoung Il Choi1orcid, Jae Myung Cha1,2orcid

DOI: https://doi.org/10.5217/ir.2025.00188
Published online: January 2, 2026

1Department of Gastroenterology, Kyung Hee University Hospital at Gangdong, Seoul, Korea

2Department of Gastroenterology, Kyung Hee University School of Medicine, Seoul, Korea

Correspondence to Jae Myung Cha, Department of Gastroenterology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 892 Dongnam-ro, Gangdong-gu, Seoul 05278, Korea. E-mail: drcha@khu.ac.kr
• Received: August 22, 2025   • Revised: September 23, 2025   • Accepted: September 28, 2025

© 2026 Korean Association for the Study of Intestinal Diseases.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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  • Population-based colonoscopy screening is considered one of the most effective strategies for reducing the incidence and mortality of colorectal cancer. Its major strength lies in its dual benefits: early detection of colorectal cancer and prevention via the removal of precancerous lesions. Colonoscopy has a high sensitivity and provides a full colonic evaluation in a single session, thereby reducing the need for frequent testing. However, this approach has notable limitations. Colonoscopy is an invasive procedure associated with rare but serious complications such as perforation and bleeding. Participation rates tend to be lower than those of noninvasive methods like fecal immunochemical tests. Additionally, implementing colonoscopy as a population-based tool requires significant resources, including trained endoscopists, endoscopy facilities, and financial investments. The quality of colonoscopy may also vary depending on the operator’s skill and adherence to guidelines. Given these trade-offs, population-based colonoscopy screening must be carefully evaluated in terms of cost-effectiveness, feasibility, and public acceptance within each country’s healthcare system. Therefore, population-based colonoscopy screening should be approached with a balanced understanding of its benefits and limitations to ensure cost-effectiveness, feasibility, alignment with each country’s healthcare infrastructure, and integration with existing screening programs.
  • Keywords: Colonoscopy; Colorectal neoplasms; Mass screening; Population; Quality control
Colorectal cancer (CRC) is the third most commonly diagnosed malignancy and the second leading cause of cancer death worldwide [1]. Global estimates for 2020 included over 1.9 million new CRC cases and 930,000 deaths, and this burden is projected to increase to 3.2 million new cases and 1.6 million deaths by 2040 [2]. In 2022, CRC incidence and mortality were ranked fourth and fifth, respectively, out of 36 cancers in 185 countries [3]. Historically, CRC was considered a Western disease; however, 46.6% of the global incidence and 46.2% of the global mortality now occur in Asian countries [3]. Among Asian countries in 2020, estimated age-standardized CRC incidence rates were highest in Japan (38.5/100,000), followed by Brunei Darussalam (34.9/100,000), Singapore (33.0/100,000), Korea (27.2/100,000), and China (23.9/100,000) [2]. In Korea, CRC ranks second in incidence and third in mortality out of the top 10 most common cancers according to the 2022 annual cancer statistics (Fig. 1).
The adenoma–carcinoma sequence is a well-established model that explains the multi-step progression of CRC from normal mucosa to adenoma and eventually to carcinoma [4]. Early detection of CRC can improve survival rates, allow for less aggressive treatment, and reduce the incidence and mortality of CRC, thereby decreasing its financial and public health burden. The U.S. Multi-Society Task Force on CRC recommends colonoscopy every 10 years and annual fecal immunochemical testing (FIT) as tier 1 screening [5]. For CRC screening in average-risk adults, annual FIT is recommended by the American Cancer Society [6] and U.S. Preventive Services Task Force Recommendation Statement [7]. FIT is frequently used in organized screening programs because of the noninvasive nature, low cost, and ease of administration. However, FIT has a lower diagnostic accuracy for CRC and advanced adenoma than colonoscopy. According to a systematic review and meta-analysis of 19 studies published between 1996 and 2013, the pooled sensitivity and specificity of FIT were 78% and 95%, respectively [8]. In addition, the positive and negative likelihood ratios of detecting CRC were 13.1 and 0.23, respectively [8]. Therefore, opportunistic screening at the individual level is most commonly performed using colonoscopy, which is considered the gold standard for CRC screening. However, it has several limitations as an organized screening tool. This review describes the strengths and limitations of population-based screening colonoscopy.
1. Dual Benefit of Colonoscopy
Given the well-established adenoma–carcinoma sequence in CRC development, CRC is largely preventable by detecting and removing precancerous lesions using colonoscopy [9,10]. Screening tools for other types of cancers are primarily aimed at early detection, whereas colonoscopy offers the additional advantage of preventing CRCs by removing precancerous lesions. Therefore, screening colonoscopy not only improves survival but also allows for less aggressive treatment and helps reduce the overall public health and economic burden. With the increasing incidence of CRC in transitioning countries and among younger adults, improved CRC screening tools are urgently needed to reduce future cases and deaths [10].
CRC screening can be delivered using organized or opportunistic approaches, with organized screening being particularly important because of its structured implementation, quality assurance, and potential population-based impact. A recent community-based study in the United States demonstrated the effectiveness of organized CRC screening on screening uptake, incidence, and mortality; organized screening tests were systematically and comprehensively performed using validated methods, consisting primarily of FIT, colonoscopy, and sigmoidoscopy [11]. Initiation of organized CRC screening significantly increased the up-to-date screening status from 38.9% in 2000 to 82.7% in 2015. Higher rates of organized screening were associated with a 25.5% reduction in annual CRC incidence between 2000 and 2015, from 95.8 to 71.4 cases/100,000, and a 52.4% reduction in cancer mortality, from 30.9 to 14.7 deaths/100,000.
Currently, colonoscopy is primarily used as an opportunistic screening modality and has not yet been widely adopted as an organized screening tool. However, given that more than 2.5 million colonoscopies were performed in South Korea in 2023, careful consideration should be given to initiating discussions on the use of colonoscopy as an organized screening tool.
2. Growing Body of Evidence
In the National Polyp Study, 2,602 patients were prospectively referred for initial colonoscopy between 1980 and 1990, and the standardized incidence-based mortality ratio was 0.47 (95% confidence interval [CI]=0.26–0.80) among patients who underwent colonoscopic polypectomy, indicating a 53% reduction in CRC mortality based on an expected 25.4 CRC-related deaths in the general population [12]. In addition, many observational studies have demonstrated the protective effect of screening colonoscopies (Table 1) [13-18]. Screening colonoscopy has been associated with an approximately 70% decrease in CRC incidence and a 78% to 88% decrease in CRC mortality, indicating its strong potential for disease prevention. However, a key limitation of observational studies is their inability to account for participation rates.
Therefore, the results of randomized controlled trials (RCTs) are expected to provide more definitive evidence. To date, 4 large-scale RCTs have compared the effect of screening colonoscopy with either FIT or no screening on CRC mortality after 10 to 15 years (Table 2) [19,20]. The NordICC and COLONPREV trials have completed their initial screening rounds, whereas the CONFIRM and SCREESCO trials are currently enrolling participants. In the NordICC trial (n=84,585), 28,220 participants were assigned to the invited group (42.0% of whom underwent screening colonoscopy) and 56,365 participants were assigned to the usual-care group [21]. In intention-to-screen analyses over a median follow-up of 10 years, the risk of CRC was 0.98% in the invited group and 1.20% in the usual-care group, a risk reduction of 18% (risk ratio, 0.82; 95% CI, 0.70–0.93) [21]. The risk of death from CRC was 0.28% in the invited group and 0.31% in the usual-care group (risk ratio, 0.90; 95% CI, 0.64–1.16). Given that only 42% of the invited group participated in screening colonoscopy, adjusted per-protocol analysis at 10 years showed a 31% risk reduction in CRC incidence and a 50% risk reduction in CRC mortality [21].
The COLONPREV trial is an RCT involving asymptomatic adults aged 50 to 69 years, comparing one-time colonoscopy (n=26,703) with FIT every 2 years (n=26,599) [22]. Eligible participants were presumably healthy adults without a personal history of CRC, adenoma, or inflammatory bowel disease; family history of hereditary or familial CRC; severe comorbidities; or previous colectomy. The participation rate was significantly higher in the FIT group than in the colonoscopy group (34.2% vs. 24.6%, P<0.001). CRC was identified in 30 patients (0.1%) in the colonoscopy group and 33 patients (0.1%) in the FIT group (odds ratio, 0.99; 95% CI, 0.61–1.64; P=0.99). In the final results of the COLONPREV trial [23], participation in any form of screening was 31.8% and 39.9% in the colonoscopy and FIT groups, respectively. FIT was non-inferior to colonoscopy with regard to the risk of CRC mortality at 10 years; the risk of mortality was 0.22% in the colonoscopy group and 0.24% in the FIT group (risk difference, –0.02, 95% CI, –0.10 to 0.06; risk ratio, 0.92; 95% CI, 0.64 to 1.32; Pnon-inferiority=0.0005).
Although the reduction in mortality associated with screening colonoscopy in RCTs has been less pronounced than that in observational cohort studies, these differences should be interpreted with caution. RCTs typically use intention-to-treat analyses, counting all randomized participants regardless of whether they actually underwent colonoscopy. Low adherence in the intervention arm can attenuate the observed effects. For example, the participation rate for screening colonoscopy was 42.0% in the NordICC trial [21] and 31.8% in the COLONPREV trial [23]. RCTs often enroll lower-risk or more health-conscious populations compared with real-world observational cohorts, which can reduce the absolute effect size. Moreover, although previous studies [21,23] have evaluated the risk of CRC mortality at 10 years, the mortality reduction due to screening colonoscopy may require a longer follow-up period to become fully evident. Therefore, the results of the 2 ongoing RCTs (the CONFIRM and SCREESCO trials) and extended follow-up data from the 2 previous trials (the NordICC and COLONPREV trials) should be interpreted carefully.
3. Korean Colonoscopy Screening Pilot Study
The Korean Colonoscopy Screening Pilot Study (K-cospi) was developed to evaluate the effectiveness of screening colonoscopy in reducing CRC incidence, assess screening-related complications, and determine whether colonoscopy is an acceptable primary modality for the National Cancer Screening Program (NCSP) in Korea [24]. The target population was 26,640 participants aged 50 to 74 years residing in 3 cities (Goyang, Gimpo, and Paju). Data from this pilot study were linked to diagnostic workup results, the Korean Cancer Registry, and death certificate data to analyze the performance, long-term effects, and cost-effectiveness of screening colonoscopy.
The major findings of the K-cospi trial are summarized in Table 3. A total of 26,004 participants were eligible for inclusion, of whom 24,929 were included in the final analysis, representing participants from a variety of healthcare institutions. Colonoscopy quality indicators, including the proportion of adequate bowel preparations, cecal intubation rate, and withdrawal time ≥6 minutes, substantially exceeded the quality targets [25,26]. The adenoma detection rate (ADR) in the K-cospi trial was 44.3%, which was greater than the 35% benchmark for colonoscopy quality indicators [26]. Considering that the CRC detection rate from the FIT-based NCSP in 2021 was 0.09%, the CRC detection rate observed in the K-cospi trial was markedly higher at 0.5%. Furthermore, the K-cospi trial detected CRC at an earlier stage, with a higher proportion of cases at a localized stage (51.4% vs. 39.8%) and a lower proportion of cases at a distant stage (13.1% vs. 15.6%), compared with the FIT-based NCSP. Colonoscopy-associated adverse events were mostly mild, with only 0.1% of cases experiencing moderate bleeding requiring hospitalization; severe adverse events were rare, including perforation (n=2, 0.0%) and death (n=0, 0.0%).
The K-cospi trial demonstrated that population-based screening colonoscopy achieved a higher CRC detection rate at earlier stages than the FIT-based NCSP, while also being performed with a favorable safety profile. However, it is likely that more experienced endoscopists were involved in the trial, as only those who had completed a certain level of training and certification were eligible to participate. The results of K-cospi trial may not accurately reflect the current performance of general endoscopists in Korea, and therefore require careful interpretation.
Colonoscopy is the gold standard for CRC screening. However, FIT is primarily used for organized screening, whereas colonoscopy is most often performed as an opportunistic screening modality. Colonoscopy has several limitations as an organized screening tool, such as safety concerns, low participation rates, variable quality, colonoscopy capacity and human resources, substantial infrastructure and workforce requirements, and a significant economic burden.
1. Safety Concerns
As the safety profiles of colonoscopies differ between hospital-based and population-based implementation, only safety data from population-based colonoscopies are reviewed in this article. A systematic review and meta-analysis analyzed 21 studies on population-based colonoscopies with data from more than 1.9 million colonoscopies performed between 2001 and 2015 [27]. The pooled occurrence rates for perforation, post-colonoscopy bleeding, and mortality were 0.5/1,000 (95% CI, 0.4–0.7), 2.6/1,000 (95% CI, 1.7–3.7), and 2.9/100,000 (95% CI, 1.1–5.5), respectively. Colonoscopy with polypectomy was associated with a perforation rate of 0.8/1,000 (95% CI, 0.6–1.0) and a post-polypectomy bleeding rate of 9.8/1,000 (95% CI, 7.7–12.1). Time-trend analysis showed that post-procedural bleeding declined from 6.4/1,000 to 1.0/1,000 between 2001 and 2015, whereas perforation and mortality rates remained stable. However, the safety data for population-based colonoscopies should be interpreted in the context of each country’s local data because considerable heterogeneity was observed in most analyses. The rates of perforation, post-colonoscopy bleeding, and mortality reported in the systematic review and meta-analysis differed substantially from those observed in the domestic K-cospi trial. These discrepancies may be explained by differences in study design, endoscopist experience, quality assurance programs, patient selection criteria, and healthcare system infrastructure. In particular, colonoscopy-associated perforation and death are extremely rare; consequently, the sample size of the K-cospi trial may have been insufficient to accurately assess these severe adverse events, raising the possibility that their risks were underestimated. In the NordICC trial, which implemented population-based screening colonoscopy, 15 participants experienced major bleeding after polyp removal; however, no perforations or screening-related deaths occurred within 30 days of the procedure [21]. These findings suggest that population-based colonoscopy can be performed with a relatively favorable safety profile.
A population-based study of 1.58 million colonoscopies performed between 2005 and 2011 compared adverse events related to colonoscopy with those of other low-risk procedures (joint injection, aspiration, and lithotripsy; arthroscopy and carpal tunnel release; or cataract surgery) [28]. After screening or surveillance colonoscopy, the numbers of lower gastrointestinal bleeding, perforation, myocardial infarction, and ischemic stroke per 10,000-persons without biopsy or intervention were 5.3 (95% CI, 4.8–5.9), 2.9 (95% CI, 2.5–3.3), 2.5 (95% CI, 2.1–2.9), and 4.7 (95% CI, 4.1–5.2), respectively; the numbers per 10,000-persons with biopsy or intervention were 36.4 (95% CI, 35.1–37.6), 6.3 (95% CI, 5.8–6.8), 4.2 (95% CI, 3.8–4.7), and 9.1 (95% CI, 8.5–9.7), respectively. Ranges of adjusted odds ratios for serious gastrointestinal complications, myocardial infarction, ischemic stroke, and serious pulmonary events after colonoscopy vs. comparator procedures were 2.18 (95% CI, 2.02–2.36) versus 5.13 (95% CI, 4.81–5.47), 0.67 (95% CI, 0.56–0.81) versus 0.99 (95% CI, 0.83–1.19), 0.66 (95% CI, 0.59–0.75) versus 1.13 (95% CI, 0.99–1.29), and 0.64 (95% CI, 0.61–0.68) versus 1.05 (95% CI, 0.98–1.11), respectively. This study showed that population-based colonoscopy was associated with low rates of serious gastrointestinal adverse events and similar rates of myocardial infarction, stroke, and serious pulmonary events as low-risk comparator procedures [28].
Colonoscopy is an inherently invasive procedure and colonoscopy-related complications cannot be completely prevented [29], fostering social consensus on this issue is critically important. In this consideration, legal implications including malpractice liability and broader societal concerns are also critical factors. Although the incidence of adverse events is relatively low, its consequences can be severe and requiring surgical intervention, which result in legal claims and compensation issues [30,31]. The number of medical disputes related to colonoscopy are increasing [30], and the median compensation was about 130 times the cost of a single colonoscopy in Korea [31]. To comprehensively assess the role of colonoscopy in NCSP, risk-benefit analyses should incorporate medico-legal costs to provide more robust evidence to guide policymaking in Korea. Several strategies are essential to minimize major adverse events associated with the invasive nature of colonoscopy. Careful patient selection and risk stratification, adherence to standardized guidelines (including bowel preparation, polypectomy, and hemostasis), and meticulous endoscopic techniques can reduce procedure-related adverse events. In addition, ongoing endoscopic training and quality monitoring are essential to maintain safety during population-based colonoscopies.
2. Low Participation Rates
Improving participation rates is essential for the success of population-based CRC screening programs. However, colonoscopy has been criticized for its lower participation rates compared with FIT. In fact, the participation rates for screening colonoscopy were only 42.0% and 31.8% in the NordICC and COLONPREV trials, respectively [21,23]. When individuals at average risk for CRC were randomized to receive recommendations for screening with either fecal occult blood testing or colonoscopy in the United States, only 38% completed colonoscopy screening, whereas 67% completed fecal occult blood testing [32]. Despite the high potential of colonoscopy to reduce mortality, its net effects may be attenuated by the low participation rates in population-based CRC screening. This low participation rate may be attributed to its invasive nature, perceived discomfort, logistical barriers, and patient preferences for noninvasive alternatives.
However, the participation rate of screening colonoscopy may vary based on the healthcare infrastructure and population characteristics of each country. A survey conducted in Korea in 2016 (n=396) found that more than twice as many individuals preferred colonoscopy over FIT (68.7% vs. 31.3%) [33]. In South Korea, widespread healthcare access, relatively affordable colonoscopy costs, and increasing public awareness may drive the high acceptance and utilization of colonoscopy as a primary CRC screening tool. A critical limitation of the Korean survey is the possibility of selection bias, since the participants had already taken part in the NCSP. As survey data alone are insufficient for drawing concrete conclusions, RCTs are needed to accurately assess actual participation rates in Korea.
3. Variable Quality of Colonoscopy
A substantial miss rate remains a limitation of colonoscopy, as demonstrated by tandem colonoscopy and computed tomography colonography studies. Colonoscopy has been reported to miss approximately 22% of polyps of any size, 12% of large polyps, and 11% of advanced adenomas [34-36]. Furthermore, the pooled 3-year post-colonoscopy CRC detection rate was 7.5% (95% CI, 6.4%–8.7%) in a recent systematic review and meta-analysis [37]. In the NordICC trial, recommended benchmarks for 95% cecal intubation rate and 25% ADR were not met by 17.1% and 28.6% of endoscopists, respectively [38]. These findings indicate that a substantial proportion of polyps and cancerous lesions continue to be missed, even with colonoscopy as the primary screening tool. Variability in colonoscopy quality during population-based CRC screening arises primarily from differences in endoscopist skill and experience, inadequate bowel preparation, equipment disparities, and lack of standardized quality monitoring. These factors contribute to inconsistent ADRs and complication profiles, thereby undermining screening effectiveness.
To establish successful population-based screening colonoscopy, key components include standardized quality benchmarks, rigorous endoscopist training and certification, systematic monitoring of performance indicators, effective bowel preparation protocols, equitable access to high-quality facilities, and continuous quality improvement initiatives. Of these, the most critical factor is rigorous training and certification of endoscopists. Therefore, establishing a consensus on the qualifications required for endoscopists to participate in population-based screening colonoscopy is essential, as are comprehensive education and training programs led by relevant professional societies.
It is essential to implement systematic measures to ensure and maintain procedural quality. Quality assurance can be achieved through standardized training and certification programs for endoscopists, regular audits of key performance indicators (such as ADR, cancer detection rate, withdrawal time, and complication rates), and feedback systems. National-level registries and real-time reporting platforms can also facilitate monitoring and benchmarking. Incentivizing examiners is equally important, especially given the increased workload and medico-legal risk associated with colonoscopy. In Korea, where fee-for-service reimbursement predominates, aligning compensation with quality performance could help improve examiner engagement and the overall success of population-based screening programs.
Recent studies have demonstrated that artificial intelligence (AI)-assisted colonoscopy can improve the quality of colonoscopic examinations in real-world settings. For example, computer-aided detection (CADe) systems may increase ADR, and computer-aided diagnosis (CADx) systems may assist in real-time optical characterization of lesions. A recent systematic review and meta-analysis reported that CADe increased ADR by 24% compared with standard white-light endoscopy, with a risk ratio of 1.24 [39]. Despite these promising findings, however, the clinical utility of CADe in routine practice remains limited. Challenges include a lack of proven long-term outcomes, minimal benefit observed in real-world settings, and a high false-positive rate, which may lead to overdiagnosis and overtreatment. Another systematic review and meta-analysis found no significant difference between CADx-assisted and unassisted strategies in the proportion of polyps that could have avoided pathological assessment [40]. However, the proportion of incorrectly predicted polyps was lower with CADx assistance. CADx may support “resect-and-discard” or “diagnose-and-leave” strategies by enabling real-time optical diagnosis, potentially reducing reliance on histopathologic evaluation. Nonetheless, its clinical application still remains constrained by limitations such as low sensitivity, regulatory and validation challenges, and a lack of algorithmic transparency. In a recent multicenter observational study, a decline in endoscopist performance—referred to as deskilling—was observed following exposure to AI-assisted colonoscopy [41]. The ADR of standard colonoscopy decreased from 28.4% before the introduction of AI to 22.4% afterward. In addition, most endoscopists demonstrated a lower ADR after AI exposure, with the absolute decrease ranging from 2.9% to 37.5%, suggesting a potential overreliance on AI systems during procedures. Currently, AI-assisted colonoscopy has not been widely adopted in Korea, primarily due to the lack of reimbursement and concerns regarding cost-effectiveness. Further research is warranted to validate the effectiveness of AI-based systems in improving the quality of colonoscopy in real-world settings.
4. Colonoscopy Capacity and Workforce Availability
Successful implementation of population-based screening colonoscopy requires a thorough evaluation of colonoscopy capacity and human resources. Unfortunately, no data are currently available on the colonoscopy capacity in Korea. In terms of workforce availability, the total number of certified endoscopists in South Korea was 7,661, with 5,828 maintaining active certification in October 2024. However, 49.4% of these endoscopists were concentrated in Seoul and Gyeonggi province, indicating that the sustainability of the system and regional disparities warrant careful consideration. The current NCSP and K-cospi trial in South Korea have applied colonoscopist assurance criteria based on training and education. For participation in the NCSP, the requirements included the following: (1) supervised colonoscopy training for over 1 year; (2) performance of more than 150 cumulative colonoscopies; and (3) at least 12 hours of endoscopy-related education every 3 years. Eligibility for the K-cospi trial required a similar level of experience, with the performance of more than 150 cumulative colonoscopies over 2 years and membership in the Korean Society of Gastrointestinal Endoscopy, Korean Society of Digestive Endoscopy, or Korean Society of Coloproctology. Colonoscopist assurance criteria based on training and education are considered a minimum safeguard for quality control in population-based screening colonoscopy.
A study using the Microsimulation Screening Analysis-Colon model determined that the estimated colonoscopy capacity is sufficient to screen 80% of the eligible U.S. population with FIT, colonoscopy, or a mix of tests by 2024 if a national screening program was started in 2014 [42]. Over a period of 10 years in the USA, a FIT-based program would require approximately 47 million FITs and 5.1 million colonoscopies annually to screen the eligible population, whereas a colonoscopy-based program would require approximately 11–13 million colonoscopies [42]. Therefore, precise microsimulation screening analyses for the current and future colonoscopy capacity are essential for designing a population-based screening colonoscopy program in each country.
From this perspective, Japan’s strategy provides valuable insights into population-based CRC screening. A base-case analysis using a Markov model of population-based CRC screening demonstrated that FIT, colonoscopy, and a combined colonoscopy and FIT approach were superior to the noscreening option, and a colonoscopy-based strategy appeared to be the most cost-effective in Japan [43]. However, the colonoscopy-based strategy required more than double the number of total colonoscopy procedures than the other strategies. Depending on the total colonoscopy capacity, adding total colonoscopy for individuals at a specified age to a FIT-based screening program has been suggested as an optimal strategy in Japan. As demonstrated in simulation model analyses in the United States and Japan [42,43], interpreting simulation outcomes in conjunction with each country’s colonoscopy capacity is essential for developing a well-balanced population-based screening colonoscopy program.
5. Economic Burden
One of the key elements that must be considered when implementing a population-based CRC screening program is economic burden. A successful screening program should be effective in reducing CRC incidence and mortality, as well as cost-effective and sustainable within the healthcare system. This includes evaluating the direct costs of screening methods (e.g., FIT vs. colonoscopy), indirect costs such as patient time and transportation, and long-term savings associated with the early detection and prevention of CRC.
In the current NCSP in Korea, the cost of one FIT is ₩14,560 (KRW 14,560). If FIT was conducted annually over 10 years, the cumulative cost would be ₩145,600. In comparison, the cost of a colonoscopy without biopsy, sedation, or polypectomy is ₩130,980, suggesting a comparable level of financial resources if screening colonoscopy is performed once every 10 years. Moreover, indirect costs, such as transportation for 10 separate FIT visits and the added benefit of CRC prevention and stage shifting using colonoscopy, should be considered. A shift toward earlier detection and prevention via colonoscopy may lead to long-term reductions in the overall financial burden on the National Health Insurance system, potentially offsetting the upfront costs of implementing colonoscopy-based screening programs.
We conducted a comparative analysis of 35 screening strategies, varying by starting age (45, 50, and 55 years), age limit (69, 74, 79, and 84 years, and no upper limit), and screening interval (5, 10, and 15 years) (data not yet published). Of these strategies, colonoscopy screening starting at 45 years of age with 5-, 10-, or 15-year intervals demonstrated favorable efficiency ratios. In the cost-effectiveness analysis, the strategy of screening between the ages of 45 and 74 years every 15 years was identified as the most cost-effective option. However, a 10-year screening interval is generally recommended for average-risk populations, and this interval maintained a reasonable cost-effectiveness ratio on the efficiency frontier. Given Korea’s high accessibility to endoscopy services, well-established infrastructure of trained specialists, and strong public interest and preference for screening colonoscopy, implementing a 10-year colonoscopy interval is expected to not only offer psychological reassurance but also encourage more proactive CRC management. Ultimately, this could lead to higher participation rates in organized CRC screening programs.
When considering the economic burden, it is important to refer to the cost-effectiveness studies of FIT compared with colonoscopy for CRC screening. When National Health Insurance coverage was set at 50%, with screening compliance at 45% and follow-up compliance at 65%—parameters that closely reflect real-world conditions in Korea, colonoscopy was a non-dominated strategy compared with no screening and annual FIT [44]. Across all scenarios involving varying compliance rates, increased National Health Insurance coverage, and higher reimbursement for colonoscopy, performing colonoscopy every 10 years resulted in either lower or minimally incremental medical costs and financial burden compared with no screening. When comparing multiple CRC screening scenarios using a Markov model that incorporated varying starting ages (40, 45, and 50 years), screening intervals, and stopping ages, biennial FIT screening from ages 45 to 80 emerged as the most cost-effective strategy [45]. However, this study did not include a comparison with screening colonoscopy. Therefore, further research is warranted to evaluate the cost-effectiveness of screening colonoscopy to support evidence-based decision-making in the Korean healthcare system.
Only few countries have adopted population-based CRC screening strategies involving colonoscopy, reflecting variations in healthcare infrastructure, resource availability, and population compliance. In Poland, a pilot program offers a “once-in-a-lifetime” colonoscopy to average-risk individuals, which reduces long-term resource demands but may be limited by participation rates and the scheduling of CRC screening [46]. Germany and the Czech Republic have implemented age-stratified strategies, providing annual FIT for individuals aged 50–54, followed by biennial FIT or decennial colonoscopy [47]. In this model, colonoscopy serves primarily as a second-tier test or an alternative for older age groups. This strategy offers flexibility and potential cost-effectiveness, but faces challenges related to colonoscopy capacity and workforce availability. Colonoscopy is being evaluated as the primary screening method within a regional program in Burgenland region of Austria, Kaiser Permanente North Carolina and Veterans Health Administration region of United States [5,48]. Finally, Turkey has established a population-based program offering biennial FIT or decennial colonoscopy for individuals aged 50–70 [49]. In this model, colonoscopy is available as an optional screening tool, however, its utilization may be constrained by infrastructural limitations and variability in public engagement, necessitating ongoing policy attention and resource planning. No country has yet implemented a population-based screening colonoscopy on a regular basis as the primary screening test.
While population-based colonoscopy screening offers clear benefits, such as early detection and prevention of CRC via the removal of precancerous lesions, it also presents several challenges that must be carefully considered. These include high costs, infrastructure and workforce requirements, variability in procedural quality, lower participation rates compared with noninvasive methods, public acceptance, and the need for integration with existing screening programs. Therefore, implementing colonoscopy as a population-based screening tool requires a balanced assessment of its strengths and limitations.

Funding Source

The author received no financial support for the research, authorship, and/or publication of this article.

Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Data Availability Statement

Data sharing is not applicable as no new data were created or analyzed in this study.

Author Contributions

Study concept and design: all authors. Data acquisition: all authors. Data analysis and interpretation: all authors. Drafting of the manuscript: Choi HI.. Critical revision of the manuscript for important intellectual content: Cha JM. Approval of the final manuscript: all authors.

Fig. 1.
Annual cancer statistics of Korea in 2022. CRC ranks second in incidence and third in mortality out of the top 10 most common cancers in Korea. CRC, colorectal cancer; GB, gallbladder; NHL, non-Hodgkin lymphoma.
ir-2025-00188f1.jpg
Table 1.
Observational Studies for the Colonoscopy Screening
Country Study period Design Mortality Incidence
Germany [13] 2003–2010 Case-control Not reported OR, 0.09 (95% CI, 0.07–0.13)
USA [14] 1988–2012 Cohort HR, 0.32 (95% CI, 0.24–0.45) Not reported
USA [15] 2006–2008 Case-control Not reported OR, 0.30 (95% CI, 0.15–0.59)
Switzerland [16] 2001–2007 Cohort OR, 0.12 (95% CI, 0.01–0.93) OR, 0.31 (95% CI, 0.16–0.59)
USA [17] 1989–2007 Cohort SMR, 0.35 (95% CI, 0.00–1.06) SIR, 0.33 (95% CI, 0.10–0.62)
Canada [18] 1997–2000 Case-control Not reported OR, 0.69 (95% CI, 0.44–1.07)

OR, odds ratio; CI, confidence interval; HR, hazard ratio; SMR, standardized mortality ratio; SIR, standardized incidence ratio.

Table 2.
Randomized Controlled Trials for the Population-Based Colonoscopy Screening [19,20]
Study Country Age (yr) Sample size Design Primary outcome
NordICC [21] (from 2009) Poland, Norway, Sweden, Netherlands 55–64 94,959 Effectiveness trial of CS vs. usual care (1:2) 15-yr mortality
COLONPREV [22,23] (from 2009) Spain 50–69 57,404 Non–inferiority trial of CS vs. biennial FIT 10-yr mortality
CONFIRM (from 2012) USA 50–75 55,000 Superiority trial of CS vs. annual FIT 10-yr mortality
SCREESCO (from 2014) Sweden 59–62 200,000 Effectiveness trial of CS vs. biennial FIT vs. no screening (1:3:6) 15-yr mortality

CS, colonoscopy; FIT, fecal immunochemical test.

Table 3.
Major Findings from the Korean Colonoscopy Screening Pilot Study (K-cospi) [24]
Variable Results (n=26,004), No. (%) References
Distribution of medical institution
 General hospital 9,743 (34.5)
 Hospital 6,191 (23.8)
 Primary clinic 10,070 (38.7)
Colonoscopy quality data
 Adequate preparation (excellent-fair) 24,960 (96.0) 90b
 Cecal intubation 25,855 (99.4) 95b
 Withdrawal time ≥ 6 min (n = 979) 938 (95.8) 90b
Colonoscopy outcome data
 Adenoma detection rate 11,512 (44.3) 35b
 Polyp detection rate 16,123 (62.0)
 Cancer detection rate 141 (0.5) 0.09c
 Cancer stages (SEER)a
  Localized 55 (51.4) 39.8c
  Regional 24 (22.4) 38.4c
  Distant 14 (13.1) 15.6c
Colonoscopy-associated AEs
 Mild
  Pain 220 (0.9)
  Bleeding 44 (0.2)
 Moderate, requiring hospitalization
  Pain 3 (0.0)
  Bleeding 13 (0.1)
 Severe
  Bleeding requiring transfusion 0
  Perforation 2 (0.0)
  Death 0

a Fourteen cases (13.1%) were of unknown stage and were excluded from the description.

b Target of quality indicator.

c National Cancer Screening Program data (2021).

SEER, Surveillance, Epidemiology, and End Result; AEs, adverse events.

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      Population-based screening colonoscopy in Korea: balancing benefits and limitations
      Image
      Fig. 1. Annual cancer statistics of Korea in 2022. CRC ranks second in incidence and third in mortality out of the top 10 most common cancers in Korea. CRC, colorectal cancer; GB, gallbladder; NHL, non-Hodgkin lymphoma.

      Fig. 1.

      Population-based screening colonoscopy in Korea: balancing benefits and limitations
      Country Study period Design Mortality Incidence
      Germany [13] 2003–2010 Case-control Not reported OR, 0.09 (95% CI, 0.07–0.13)
      USA [14] 1988–2012 Cohort HR, 0.32 (95% CI, 0.24–0.45) Not reported
      USA [15] 2006–2008 Case-control Not reported OR, 0.30 (95% CI, 0.15–0.59)
      Switzerland [16] 2001–2007 Cohort OR, 0.12 (95% CI, 0.01–0.93) OR, 0.31 (95% CI, 0.16–0.59)
      USA [17] 1989–2007 Cohort SMR, 0.35 (95% CI, 0.00–1.06) SIR, 0.33 (95% CI, 0.10–0.62)
      Canada [18] 1997–2000 Case-control Not reported OR, 0.69 (95% CI, 0.44–1.07)
      Study Country Age (yr) Sample size Design Primary outcome
      NordICC [21] (from 2009) Poland, Norway, Sweden, Netherlands 55–64 94,959 Effectiveness trial of CS vs. usual care (1:2) 15-yr mortality
      COLONPREV [22,23] (from 2009) Spain 50–69 57,404 Non–inferiority trial of CS vs. biennial FIT 10-yr mortality
      CONFIRM (from 2012) USA 50–75 55,000 Superiority trial of CS vs. annual FIT 10-yr mortality
      SCREESCO (from 2014) Sweden 59–62 200,000 Effectiveness trial of CS vs. biennial FIT vs. no screening (1:3:6) 15-yr mortality
      Variable Results (n=26,004), No. (%) References
      Distribution of medical institution
       General hospital 9,743 (34.5)
       Hospital 6,191 (23.8)
       Primary clinic 10,070 (38.7)
      Colonoscopy quality data
       Adequate preparation (excellent-fair) 24,960 (96.0) 90b
       Cecal intubation 25,855 (99.4) 95b
       Withdrawal time ≥ 6 min (n = 979) 938 (95.8) 90b
      Colonoscopy outcome data
       Adenoma detection rate 11,512 (44.3) 35b
       Polyp detection rate 16,123 (62.0)
       Cancer detection rate 141 (0.5) 0.09c
       Cancer stages (SEER)a
        Localized 55 (51.4) 39.8c
        Regional 24 (22.4) 38.4c
        Distant 14 (13.1) 15.6c
      Colonoscopy-associated AEs
       Mild
        Pain 220 (0.9)
        Bleeding 44 (0.2)
       Moderate, requiring hospitalization
        Pain 3 (0.0)
        Bleeding 13 (0.1)
       Severe
        Bleeding requiring transfusion 0
        Perforation 2 (0.0)
        Death 0
      Table 1. Observational Studies for the Colonoscopy Screening

      OR, odds ratio; CI, confidence interval; HR, hazard ratio; SMR, standardized mortality ratio; SIR, standardized incidence ratio.

      Table 2. Randomized Controlled Trials for the Population-Based Colonoscopy Screening [19,20]

      CS, colonoscopy; FIT, fecal immunochemical test.

      Table 3. Major Findings from the Korean Colonoscopy Screening Pilot Study (K-cospi) [24]

      Fourteen cases (13.1%) were of unknown stage and were excluded from the description.

      Target of quality indicator.

      National Cancer Screening Program data (2021).

      SEER, Surveillance, Epidemiology, and End Result; AEs, adverse events.

      Table 1.

      Table 2.

      Table 3.

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      © Korean Association for the Study of Intestinal Diseases.
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