The National Cancer Screening Program (NCSP) for gastric cancer and colorectal cancer (CRC) has been employed for Medical Aid recipients and National Health Insurance beneficiaries in the lower 50% income bracket in Korea.1234 In the NCSP, esophagogastroduodenoscopy (EGD) is conducted biennially for individuals aged ≥40 years,23 whereas annual fecal immunochemical test (FIT) and confirmatory colonoscopy are performed for those aged ≥50 years with positive FIT results.4

Since 2009, the quality indicators of EGD and colonoscopy have been measured through the National Endoscopy Quality Improvement Program (NEQIP) of the NCSP.567 The NEQIP includes indicators for the qualifications of endoscopists, quality improvement for instruments available at the endoscopy unit, endoscopic process, and measurement of outcomes for endoscopy screening.7 In Western countries, the quality indicators of EGD and colonoscopy have been recently revised on the basis of updated evidence.8910 The NEQIP was also revised; however, many quality indicators of the NEQIP were based mostly on expert opinion and variable levels of supporting evidence.11 Therefore, whether the revised NEQIP could represent relevant quality indicators and outcome measures of EGD and colonoscopy in the NCSP is questionable. Real-world evaluation of the revised NEQIP in clinical practice may be the first step towards successful widespread adoption of the NEQIP.

In this study, we evaluated the quality indicators of the revised NEQIP and outcome measures of EGD and colonoscopy performed at primary, secondary, and tertiary healthcare facilities participating in the NCSP.

We invited 17 representative endoscopists from 16 endoscopy units, and 15 of them responded for a participation rate of 88.2%. The complete overall response rate was 88.2% as there were no incomplete answers. Five (33.3%), seven (46.7%), and three (20.0%) of the respondents were working at primary clinics, secondary, and tertiary hospitals, respectively.

This is the first study to investigate quality indicators of the NEQIP and outcome measures of endoscopy in the NCSP according to healthcare facility type in Korea. Among the quality indicators of the NEQIP, most were close to optimal; however, the quality indicators for annual volume of EGD and colonoscopy, training for endoscopy quality improvement by endoscopy nursing staff, colonoscopy reports, documentation of pathologic lesions, quality of endoscopy reprocessing areas, and completion of endoscopy reprocessing education programs were not adequate.

In the NEQIP, the recommended annual volume of EGD and colonoscopy cases are 100 and 50, respectively.11 No consensus is reported on the minimum number of annual EGDs, whereas 150–200 annual colonoscopies are recommended in guidelines.1012 The European Society of Gastrointestinal Endoscopy (ESGE) recommends a minimum number of annual colonoscopies to be performed.10 The National Health Service Bowel Cancer Screening Programme of the United Kingdom and the Spanish Society of Gastrointestinal Endoscopy recommend at least 150 and 200 annual colonoscopies for their respective National CRC Screening Programs.10 Harewood13 reported an annual volume of at least 200 colonoscopies are required to maintain adequate competence among junior endoscopists. Considering suboptimal levels in the annual volumes of endoscopies in the present study, quality improvement programs may be advised to focus on low-volume endoscopists and endoscopy units. The US guidelines have suggested CME to maintain proficiency for endoscopists and endoscopy nursing staff,1415 however, education for the latter was not adequate in the NEQIP. Therefore, CME should be emphasized for the endoscopy nursing staff in the NCSP.

As the quality of endoscopy is closely associated with the quality of the endoscopy report, accurate endoscopy reporting is one of the main goals of the NEQIP.1116 The endoscopy report helps to exchange information on endoscopic findings, treatments, clinical recommendations, and adverse effects.1718 Suboptimal performance for colonoscopy reports and documentation of pathologic lesions in the NEQIP may be associated with a lack of awareness of the importance of accurate endoscopy reports and high endoscopy workloads in daily clinical practice. However, it is not easy to demonstrate a negative association between high endoscopy workloads and poor reports/documentations of colonoscopy because their objective measurement is difficult. In the reprocessing domain, the endoscopy examination area should be separated from the reprocessing area, because completely sterilized endoscopes may be re-contaminated during storage.1920 In the NEQIP, over 50% of endoscopists and reprocessing personnel are required to complete endoscopy reprocessing education programs.11 The suboptimal performance level for the quality of reprocessing areas and completion of endoscopy reprocessing education programs in the NEQIP may be associated with a lack of training in infection control and poor infrastructure for primary clinics.

For the outcome measures of EGD, the number of photo-documentations and total procedure times of EGD were significantly higher at tertiary healthcare facilities. The recommended minimum numbers of photo-documentations for EGD are 10 according to an ESGE quality improvement initiative17 and 8 according to the NEQIP, respectively.11 In this regard, the number of photo-documentations for EGD was excellent regardless of healthcare facility type in the current study. The total procedure time of EGD was also suggested as a potential quality indicator of EGD.17 It could be a outcome measure of EGD, which is comparable to the withdrawal time of colonoscopy; however, it is based only on limited evidence, and the cutoff procedure time varied from 3 to 7 minutes for EGD.212223 Biopsy rate could be considered as a quality indicator of EGD, as it has been shown to be associated with efficacy in gastric premalignant conditions, as well as with the rate of missed gastric cancers.24 However, it was not different among the different healthcare facility types. Precancerous/cancerous lesion detection rates in EGD could also be an important performance measure. However, no agreement has been reached on a specific cutoff for the detection of precancerous/cancerous lesions in the NEQIP because of inconsistency in supporting evidence.11 Furthermore, the proportions of EGDs with precancerous/cancerous lesions did not differ according to healthcare facility type. As the number of cases of precancerous/cancerous lesion was to small to analyze associations with total procedure time, biopsy, or photo-documentation, further larger studies are needed.

Regarding the outcome measures of colonoscopy, the colonoscopy completion rate and waiting time to colonoscopy were significantly higher at tertiary healthcare facilities. In US guidelines,25 the colonoscopy completion rate for those with a positive FIT should be more than 80%. In this regard, colonoscopy completion rate was only optimal at tertiary healthcare facilities in the current study. However, our results should cautiously be interpreted because colonoscopy could be performed at the cost of oneself (i.e., outside of NCSP) at primary and secondary healthcare facilities when participants had a positive FIT. Colonoscopy registry with a tracking system may be able to increase colonoscopy completion rates for those with a positive FIT. The waiting time to colonoscopy after obtaining a positive FIT result was 39.7 days in our previous study.26 A Spanish working group recommends an optimal waiting time to colonoscopy of less than 42 days.12 In a microsimulation model,27 12 months of waiting time to colonoscopy after obtaining a positive FIT result can yield proportional losses of screening benefits, according to a study in the US. In addition, longer waiting time for colonoscopy after obtaining a positive FIT result has been shown to be associated with an increased risk of neoplasia.28 However, waiting time for colonoscopy after a positive FIT is not an important issue in Korea, because median waiting times to colonoscopy are less than 45 days (1.5 months) regardless of healthcare facility type. The most important measure of FIT-based screening may be the AN detection rate; however, it was not suggested as a quality indicator in US guidelines owing to the low likelihood of those findings and the progressive reduction in those findings with subsequent series of FITs.25 The US guidelines suggested a 35–45% adenoma detection by colonoscopy as an outcome measure.25 In this regard, the outcome measure of the current study may be optimal, as the median proportions of colonoscopies with adenoma ranged from 41.6–50.0% regardless of healthcare facility type. The positive rate of FIT results was also suggested as a potential quality metrics for FIT,29 however, the proportion of positive FITs did not significantly differ according to healthcare facility type in this study.

Our study results need to be interpreted with caution in the context of potential limitations. The generalizability of the study results may be limited, owing to selection bias of the survey respondents, as they were all gastroenterologists and completed gastrointestinal fellowship training. In addition, our results may not be generalizable to other endoscopists who do not perform endoscopy in the NCSP. A larger survey from variable endoscopy settings may be warranted to overcome this limitation. Furthermore, the sample size was small. It was very difficult to enroll a large enough number of physicians who are willing to provide endoscopy quality data for the NCSP. Our respondents were representative endoscopists of each endoscopy units and presented actual clinical setting data in the NCSP. Previous studies based on the NCSP were limited by retrospective data collection, which is inaccurate, biased, and not representative of daily clinical practice. However, our data collection has minimal bias as the participating respondents fully agreed with the aim and the design of our study and collected data. Therefore, our findings reflect important NCSP data, despite the small sample size. The performance level of outcome measures was considered as “optimal” when the performance level was ≥85% among the participants in this study. However, there is no standard threshold of an optimal performance, which makes our definition arbitrary. Furthermore, outcome measures were monitored at the facility level rather than at the endoscopist level in this study. Considering the feasibility and reliability of quality metrics in the NCSP, since many endoscopists do not have adequate numbers of quality events to support reliable quality measurement, measurement at the facility level should be considered.30

In conclusion, outcome measures of endoscopy should be included as quality indicators of NCSP. However, universal outcome measures for all types of healthcare facilities should be established because performance levels of some outcome measures were different in each healthcare facility type.