1.Non-operative Management of Rectal Cancer with Adjuvant Chemotherapy after Chemoradiotherapy (NORMANDY): Prospective Study
Hyebin LEE ; Hyung Ook KIM ; Jason Joon Bock LEE ; In-Gu DO ; Heon-Ju KWON ; Mi Sung KIM ; Soo-Kyung PARK ; Hyo-Joon YANG ; Yoon Suk JUNG ; Jung Ho PARK ; Dong-Il PARK ; Kyung Uk JUNG ; Eo Jin KIM ; Dong-Hoe KOO ; Hungdai KIM ; Ho-Kyung CHUN ;
Cancer Research and Treatment 2026;58(2):573-580
Purpose:
Non-operative management (NOM) has emerged as a promising organ-preserving strategy for patients with rectal cancer who achieve a clinical complete response (cCR) after neoadjuvant chemoradiotherapy (CRT). However, no standardized treatment protocol has been established for watch-and-wait strategies.
Materials and Methods:
This prospective study evaluated oncological outcomes of NOM combined with 4 months of adjuvant capecitabine. Patients with resectable rectal cancer (≤ 8 cm from the anal verge, cT2-4 or N+) underwent CRT (50-54 Gy in 25-27 fractions with capecitabine). Eight weeks post-CRT, a multidisciplinary team assessed cCR. Patients achieving cCR received six cycles of capecitabine (2 weeks on/1 week off) and were actively monitored.
Results:
Among 89 patients receiving CRT (2018-2023), 17 (19.1%) achieved cCR and were included. The median age was 65 years, and 64.7% were male. Eleven (64.7%) completed all six cycles of adjuvant therapy. After a median follow-up of 31.4 months, 11 patients (64.7%) remained disease-free. Local regrowth occurred in six patients (35.3%) with 2- and 4-year rates of 34.5% and 47.6%, respectively. Five underwent radical surgery, and one received transanal excision with systemic chemotherapy. At the time of assessment, 15 patients (88.2%) showed no evidence of disease, while two (11.8%) received palliative chemotherapy. All patients were alive.
Conclusion
NOM with adjuvant capecitabine showed promising oncological outcomes, offering an alternative to passive watch-and-wait approaches. Further refinement through multidisciplinary strategies is warranted.
2.Establishing an Active Vaccine Safety Surveillance System Using Large Scale Databases in Korea: Lessons and Scalable Insights for Global Application
Jin Gu YOON ; Eliel NHAM ; Yu Jung CHOI ; Min Joo CHOI ; Won Suk CHOI ; Young Kyung YOON ; Yu Bin SEO ; Hakjun HYUN ; Jung Yeon HEO ; Jin-Soo LEE ; Chung-Jong KIM ; Ji Yun NOH ; Joon Young SONG ; Hee Jin CHEONG
Journal of Korean Medical Science 2026;41(1):e47-
Vaccines are highly effective, but rare or delayed adverse events following immunization (AEFIs) require post-licensure surveillance beyond clinical trials. Korea lacks a comprehensive, active, database-based framework, yet key assets exist: nationwide claims databases (National Health Insurance Service/Health Insurance Review and Assessment Service), the national immunization registry (Korea Disease Control and Prevention Agency’s Immunization Registry Information System) for National Immunization Program (NIP) and non-NIP vaccines, and increasingly standardized hospital electronic health records.We propose a federated, code to data architecture with data linkages between these data.Implementation should adopt a common data model (CDM), standardized case definitions, latency accounting, and transparent public reporting under strong privacy governance. Major challenges include multi step administrative approvals for data linkage, incomplete capture of adult non-NIP vaccinations, heterogeneous hospital data structures, and strict data protection constraints. Strategic priorities are to streamline statutory and administrative processes for public health use, mandate or enable claims-based capture of adult vaccinations, enhance CDM based interoperability, and develop secure hubs for aggregated outputs. With these measures, Korea will be well positioned to establish a scalable active surveillance system capable of detecting rare AEFIs, supporting transparent and evidence-based communication, and ensuring equitable injury compensation grounded in domestic data.
3.Sentinel Safety Monitoring System for Adverse Events of Special Interest Associated With Non-NIP Vaccines in Korea
Hakjun HYUN ; Jung Yeon HEO ; Yu Jung CHOI ; Eliel NHAM ; Jin Gu YOON ; Ji Yun NOH ; Joon Young SONG ; Woo Joo KIM ; Won Suk CHOI ; Min Joo CHOI ; Yu Bin SEO ; Jacob LEE ; Hee Jin CHEONG
Journal of Korean Medical Science 2025;40(16):e152-
South Korea’s current vaccination policies leave a surveillance gap for non-National Immunization Program (NIP) vaccines. In this study, we proposed a sentinel surveillance approach for monitoring the safety of non-NIP vaccines. Vaccination data were collected retrospectively among patients hospitalized with pre-defined adverse events of special interest (AESI) by reviewing electronic medical records in five university hospitals. This approach incorporates expert assessment to determine the causal relationship. We confirmed that 16 patients had received non-NIP vaccines among 860 patients diagnosed with AESI.We concluded one case of preeclampsia was possibly related to tetanus-diphtheria-pertussis vaccination. We propose a multi-hospital-based, retrospective assessment system for predefined AESIs as an alternative to active vaccine safety monitoring method. These efforts are expected to enhance both the accuracy and timeliness of safety monitoring in South Korea.
4.Sentinel Safety Monitoring System for Adverse Events of Special Interest Associated With Non-NIP Vaccines in Korea
Hakjun HYUN ; Jung Yeon HEO ; Yu Jung CHOI ; Eliel NHAM ; Jin Gu YOON ; Ji Yun NOH ; Joon Young SONG ; Woo Joo KIM ; Won Suk CHOI ; Min Joo CHOI ; Yu Bin SEO ; Jacob LEE ; Hee Jin CHEONG
Journal of Korean Medical Science 2025;40(16):e152-
South Korea’s current vaccination policies leave a surveillance gap for non-National Immunization Program (NIP) vaccines. In this study, we proposed a sentinel surveillance approach for monitoring the safety of non-NIP vaccines. Vaccination data were collected retrospectively among patients hospitalized with pre-defined adverse events of special interest (AESI) by reviewing electronic medical records in five university hospitals. This approach incorporates expert assessment to determine the causal relationship. We confirmed that 16 patients had received non-NIP vaccines among 860 patients diagnosed with AESI.We concluded one case of preeclampsia was possibly related to tetanus-diphtheria-pertussis vaccination. We propose a multi-hospital-based, retrospective assessment system for predefined AESIs as an alternative to active vaccine safety monitoring method. These efforts are expected to enhance both the accuracy and timeliness of safety monitoring in South Korea.
5.Sentinel Safety Monitoring System for Adverse Events of Special Interest Associated With Non-NIP Vaccines in Korea
Hakjun HYUN ; Jung Yeon HEO ; Yu Jung CHOI ; Eliel NHAM ; Jin Gu YOON ; Ji Yun NOH ; Joon Young SONG ; Woo Joo KIM ; Won Suk CHOI ; Min Joo CHOI ; Yu Bin SEO ; Jacob LEE ; Hee Jin CHEONG
Journal of Korean Medical Science 2025;40(16):e152-
South Korea’s current vaccination policies leave a surveillance gap for non-National Immunization Program (NIP) vaccines. In this study, we proposed a sentinel surveillance approach for monitoring the safety of non-NIP vaccines. Vaccination data were collected retrospectively among patients hospitalized with pre-defined adverse events of special interest (AESI) by reviewing electronic medical records in five university hospitals. This approach incorporates expert assessment to determine the causal relationship. We confirmed that 16 patients had received non-NIP vaccines among 860 patients diagnosed with AESI.We concluded one case of preeclampsia was possibly related to tetanus-diphtheria-pertussis vaccination. We propose a multi-hospital-based, retrospective assessment system for predefined AESIs as an alternative to active vaccine safety monitoring method. These efforts are expected to enhance both the accuracy and timeliness of safety monitoring in South Korea.
6.Sentinel Safety Monitoring System for Adverse Events of Special Interest Associated With Non-NIP Vaccines in Korea
Hakjun HYUN ; Jung Yeon HEO ; Yu Jung CHOI ; Eliel NHAM ; Jin Gu YOON ; Ji Yun NOH ; Joon Young SONG ; Woo Joo KIM ; Won Suk CHOI ; Min Joo CHOI ; Yu Bin SEO ; Jacob LEE ; Hee Jin CHEONG
Journal of Korean Medical Science 2025;40(16):e152-
South Korea’s current vaccination policies leave a surveillance gap for non-National Immunization Program (NIP) vaccines. In this study, we proposed a sentinel surveillance approach for monitoring the safety of non-NIP vaccines. Vaccination data were collected retrospectively among patients hospitalized with pre-defined adverse events of special interest (AESI) by reviewing electronic medical records in five university hospitals. This approach incorporates expert assessment to determine the causal relationship. We confirmed that 16 patients had received non-NIP vaccines among 860 patients diagnosed with AESI.We concluded one case of preeclampsia was possibly related to tetanus-diphtheria-pertussis vaccination. We propose a multi-hospital-based, retrospective assessment system for predefined AESIs as an alternative to active vaccine safety monitoring method. These efforts are expected to enhance both the accuracy and timeliness of safety monitoring in South Korea.
7.Perception on the Intestinal Malrotation: A 2021 Survey Conducted by the Korean Association of Pediatric Surgeons
Hee-Beom YANG ; Min Jeng CHO ; Yu Jeong CHO ; Yoon Mi CHOI ; Jae Hee CHUNG ; Seok Joo HAN ; Jeong HONG ; Eunyoung JUNG ; Ki Hoon KIM ; Soo-Hong KIM ; Cheol-Gu LEE ; Nam-Hyuk LEE ; Ju Yeon LEE ; Sanghoon LEE ; Suk Bae MOON ; Young-Hyun NA ; So Hyun NAM ; Chaeyoun OH ; Jin Young PARK ; Junbeom PARK ; Tae-Jin PARK ; Jae Ho SHIN ; Joonhyuk SON ; Hyun-Young KIM ;
Advances in Pediatric Surgery 2025;31(2):59-65
Purpose:
To report the findings of a perception survey on intestinal malrotation conducted by the Korean Association of Pediatric Surgeons (KAPS) in 2021.
Methods:
The perceptions on intestinal malrotation regarding clinical decision making of the KAPS members were collected through web-based survey.
Results:
A total of 22 surgeons were answered for this study. The results were presented and discussed at the 37th annual meeting of KAPS, which was held in Seoul on June 18, 2021.
Conclusion
This study provides the clinical decisions of the KAPS members on the intestinal malrotation. The study is expected to be an important reference for improving pediatric surgeons’ understanding and treatment of intestinal malrotation.
8.Interim Estimates of 2023–2024Seasonal Influenza Vaccine Effectiveness Among Adults in Korea
Yu Jung CHOI ; Jang Wook SOHN ; Won Suk CHOI ; Seong-Heon WIE ; Jacob LEE ; Jin-Soo LEE ; Hye Won JEONG ; Joong Sik EOM ; Eliel NHAM ; Hye SEONG ; Jin Gu YOON ; Ji Yun NOH ; Joon Young SONG ; Hee Jin CHEONG ; Woo Joo KIM
Journal of Korean Medical Science 2024;39(15):e146-
In the 2023–2024 season, the influenza epidemic in South Korea peaked earlier than in recent years. In this study, we aimed to estimate the interim vaccine effectiveness (VE) of the influenza vaccination to prevent influenza during the early season. From November 1, 2023, to December 31, 2023, we enrolled 2,632 subjects with influenza-like illness from eight hospitals participating in hospital-based influenza morbidity and mortality surveillance. A retrospective test-negative case-control study was conducted to estimate the VE. The results showed an adjusted VE of 22.5% (95% confidence interval [CI], 6.6 to 35.8) for the total population. The adjusted VE was 22.3% (95% CI, 6.1 to 35.7) for influenza A and 9.4% (95% CI, −51.3 to 45.7) for influenza A/H1N1. Full results of the analysis will be reported.
9.Establishment of Safety Monitoring System for Vaccines Not Included in the National Immunization Program in Korea
Eliel NHAM ; Jin Gu YOON ; Min Joo CHOI ; Yu Bin SEO ; Jacob LEE ; Won Suk CHOI ; Hakjun HYUN ; Hye SEONG ; Ji Yun NOH ; Joon Young SONG ; Woo Joo KIM ; Hee Jin CHEONG
Journal of Korean Medical Science 2024;39(5):e45-
Background:
In Korea, there are no surveillance programs for vaccines that are not included in the national immunization program (NIP), and vaccine safety monitoring in the adult population is inadequate. This study aimed to establish a safety monitoring system for nonNIP vaccines in adults.
Methods:
Frequently administered non-NIP vaccines were selected. Individuals were included if they received at least one of the selected vaccines at a participating institution and provided informed consent. Solicited and unsolicited adverse events were monitored using questionnaires sent through text messages on days 1, 3, 7, 28, and 90 post-vaccination.Selected adverse events of special interest (AESIs) were monitored monthly by retrospective review of electronic medical records. Causality was assessed according to the Korea Disease Control and Prevention Agency guidelines.
Results:
Four vaccines (tetanus-diphtheria-pertussis [Tdap], pneumococcal conjugate 13-valent [PCV13], live zoster vaccine [ZVL], and recombinant zoster vaccine [RZV]) were selected, and their safety profiles were monitored at four tertiary hospitals and 10 primary care clinics. The response rates of the questionnaires on post-vaccination days 1, 7, 28, and 90 were 99.2%, 93.6%, 81.0%, and 48.7%, respectively. Of 555 AESI identified over 10 months, 10 cases received one of the selected non-NIP vaccines within 90 days of the event.
Conclusion
We are establishing the first safety monitoring system for selected non-NIP vaccines in Korea since September 2022 and report its progress as of July 2023. However, continuous government support is essential for its maintenance and improvement.
10.Effectiveness of Bivalent mRNA Booster Vaccine Against COVID-19 in Korea
Jin Gu YOON ; Jang Wook SOHN ; Won Suk CHOI ; Seong-Heon WIE ; Jacob LEE ; Jin-Soo LEE ; Hye Won JEONG ; Joong Sik EOM ; Hye SEONG ; Eliel NHAM ; Yu Jung CHOI ; Ji Yun NOH ; Joon Young SONG ; Hee Jin CHEONG ; Woo Joo KIM
Journal of Korean Medical Science 2024;39(3):e15-
Background:
Bivalent booster mRNA vaccines containing the omicron-variant strains have been introduced worldwide in the autumn of 2022. Nevertheless, the omicron subvariants evoked another large coronavirus disease 2019 (COVID-19) pandemic wave in late 2022 and early 2023.
Methods:
A retrospective, test-negative, case-control study was conducted to estimate the vaccine effectiveness (VE) of bivalent COVID-19 vaccines in 8 university hospitals between January and February 2023. The case and control groups were divided based on nasopharyngeal COVID-19 real-time polymerase chain reaction results and matched based on age, sex, hospital, and date (week) of the test performed. The VE of the BA.1- or BA.4/BA.5-based mRNA vaccines were estimated. VE was calculated using the 1−adjusted odds ratio from multivariable logistic regression.
Results:
In total, 949 patients and 947 controls were enrolled in this study. VE for the BA.4/ BA.5-based bivalent mRNA vaccine was 43% (95% confidence interval [CI], 17, 61%). In subgroup analysis based on age and underlying medical conditions, BA.4/BA.5-based bivalent mRNA vaccine was effective against old adults aged ≥ 65-years (VE, 55%; 95% CI, 23, 73%) and individuals with comorbidities (VE, 54%; 95% CI, 23, 73%). In comparison, the BA.1-based bivalent mRNA vaccine did not demonstrate statistically significant effectiveness (VE, 25%; 95% CI, −8, 49%).
Conclusion
The BA.4/BA.5-based bivalent mRNA booster vaccine provided significant protection against COVID-19 in the Korean adults, especially in the older adults aged ≥ 65 years and in individuals with underlying medical conditions.

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