Purpose: The association between the fecal microbiota and colorectal cancer (CRC) risk has been suggested in epidemiologic studies. However, data from large-scale population-based studies are lacking. Materials and Methods: In this case-control study, we recruited 283 CRC patients from the Center for Colorectal Cancer, National Cancer Center Hospital, Korea to perform 16S rRNA gene sequencing of fecal samples. A total of 283 age- and sex-matched healthy participants were selected from 890 cohort of healthy Koreans that are publicly available (PRJEB33905). The microbial dysbiosis index (MDI) was calculated based on the differentially abundant species. The association between MDI and CRC risk was observed using conditional logistic regression. Sparse Canonical Correlation Analysis was performed to integrate species data with microbial pathways obtained by PICRUSt2. Results: There is a significant divergence of the microbial composition between CRC patients and controls (permutational multivariate analysis of variance p=0.001). Those who were in third tertile of the MDI showed a significantly increased risk of CRC in the total population (odds ratio [OR], 6.93; 95% confidence interval [CI], 3.98 to 12.06; p-trend < 0.001) compared to those in the lowest tertile. Similar results were found for men (OR, 6.28; 95% CI, 3.04 to 12.98; p-trend < 0.001) and women (OR, 7.39; 95% CI, 3.10 to 17.63; p-trend < 0.001). Bacteroides coprocola and Bacteroides plebeius species and 12 metabolic pathways were interrelated in healthy controls that explain 91% covariation across samples. Conclusion Dysbiosis in the fecal microbiota may be associated with an increased risk of CRC. Due to the potentially modifiable nature of the gut microbiota, our findings may have implications for CRC prevention among Koreans.

Purpose: The association between the fecal microbiota and colorectal cancer (CRC) risk has been suggested in epidemiologic studies. However, data from large-scale population-based studies are lacking. Materials and Methods: In this case-control study, we recruited 283 CRC patients from the Center for Colorectal Cancer, National Cancer Center Hospital, Korea to perform 16S rRNA gene sequencing of fecal samples. A total of 283 age- and sex-matched healthy participants were selected from 890 cohort of healthy Koreans that are publicly available (PRJEB33905). The microbial dysbiosis index (MDI) was calculated based on the differentially abundant species. The association between MDI and CRC risk was observed using conditional logistic regression. Sparse Canonical Correlation Analysis was performed to integrate species data with microbial pathways obtained by PICRUSt2. Results: There is a significant divergence of the microbial composition between CRC patients and controls (permutational multivariate analysis of variance p=0.001). Those who were in third tertile of the MDI showed a significantly increased risk of CRC in the total population (odds ratio [OR], 6.93; 95% confidence interval [CI], 3.98 to 12.06; p-trend < 0.001) compared to those in the lowest tertile. Similar results were found for men (OR, 6.28; 95% CI, 3.04 to 12.98; p-trend < 0.001) and women (OR, 7.39; 95% CI, 3.10 to 17.63; p-trend < 0.001). Bacteroides coprocola and Bacteroides plebeius species and 12 metabolic pathways were interrelated in healthy controls that explain 91% covariation across samples. Conclusion Dysbiosis in the fecal microbiota may be associated with an increased risk of CRC. Due to the potentially modifiable nature of the gut microbiota, our findings may have implications for CRC prevention among Koreans.

Purpose: The association between the fecal microbiota and colorectal cancer (CRC) risk has been suggested in epidemiologic studies. However, data from large-scale population-based studies are lacking. Materials and Methods: In this case-control study, we recruited 283 CRC patients from the Center for Colorectal Cancer, National Cancer Center Hospital, Korea to perform 16S rRNA gene sequencing of fecal samples. A total of 283 age- and sex-matched healthy participants were selected from 890 cohort of healthy Koreans that are publicly available (PRJEB33905). The microbial dysbiosis index (MDI) was calculated based on the differentially abundant species. The association between MDI and CRC risk was observed using conditional logistic regression. Sparse Canonical Correlation Analysis was performed to integrate species data with microbial pathways obtained by PICRUSt2. Results: There is a significant divergence of the microbial composition between CRC patients and controls (permutational multivariate analysis of variance p=0.001). Those who were in third tertile of the MDI showed a significantly increased risk of CRC in the total population (odds ratio [OR], 6.93; 95% confidence interval [CI], 3.98 to 12.06; p-trend < 0.001) compared to those in the lowest tertile. Similar results were found for men (OR, 6.28; 95% CI, 3.04 to 12.98; p-trend < 0.001) and women (OR, 7.39; 95% CI, 3.10 to 17.63; p-trend < 0.001). Bacteroides coprocola and Bacteroides plebeius species and 12 metabolic pathways were interrelated in healthy controls that explain 91% covariation across samples. Conclusion Dysbiosis in the fecal microbiota may be associated with an increased risk of CRC. Due to the potentially modifiable nature of the gut microbiota, our findings may have implications for CRC prevention among Koreans.

Background: Limited data are available on the mortality rates of patients receiving extracorporeal membrane oxygenation (ECMO) support for coronavirus disease 2019 (COVID-19). We aimed to analyze the relationship between COVID-19 and clinical outcomes for patients receiving ECMO. Methods: We retrospectively investigated patients with COVID-19 pneumonia requiring ECMO in 19 hospitals across Korea from January 1, 2020 to August 31, 2021. The primary outcome was the 90-day mortality after ECMO initiation. We performed multivariate analysis using a logistic regression model to estimate the odds ratio (OR) of 90-day mortality. Survival differences were analyzed using the Kaplan–Meier (KM) method. Results: Of 127 patients with COVID-19 pneumonia who received ECMO, 70 patients (55.1%) died within 90 days of ECMO initiation. The median age was 64 years, and 63% of patients were male. The incidence of ECMO was increased with age but was decreased after 70 years of age. However, the survival rate was decreased linearly with age. In multivariate analysis, age (OR, 1.048; 95% confidence interval [CI], 1.010–1.089; P = 0.014) and receipt of continuous renal replacement therapy (CRRT) (OR, 3.069; 95% CI, 1.312–7.180; P = 0.010) were significantly associated with an increased risk of 90-day mortality. KM curves showed significant differences in survival between groups according to age (65 years) (log-rank P = 0.021) and receipt of CRRT (log-rank P = 0.004). Conclusion Older age and receipt of CRRT were associated with higher mortality rates among patients with COVID-19 who received ECMO.

Purpose: The Korean Society of Medical Education (KSME) was founded in 1983 and celebrated its 40th anniversary in 2023. This study examines the evolution of topics discussed at KSME conferences from 1971 through 2023, highlighting shifts in the focus of medical education. Methods: We analyzed 90 KSME conferences over 5 decades (1970s, 1980s, 1990s, 2000s, and 2010s), categorizing the topics into three eras based on emerging themes and continuity. Results: Consequently, 37 topics covered at the conference were categorized. Ten topics continuously appeared from the 1970s to the 2010s, including future directions of medical education, teaching methods, faculty development, and curriculum. The topics from the 1970s to the 1990s included 14 areas, such as medical education evaluation, non-undergraduate curriculum, community-related, and research. Thirteen new topics emerged after the 2000s, such as social accountability, student support, professionalism, and quality improvements. The most common topics under innovations in medical education, a case of curriculum innovation at universities that began after 2000, were clinical clerkship, curriculum development, and medical humanities. Conclusion KSME’s selection of conference topics has been strategically aligned with societal needs and the evolving landscape of medical education. Future topics should continue to address relevant societal and educational challenges.

Purpose: To evaluate the effectiveness and safety of treating choroidal melanoma and cancer that has metastasized to the choroid with gamma knife radiosurgery (GKR). Methods: We performed a retrospective chart review that included 10 eyes of eight patients with a diagnosis of choroidal tumors who underwent GKR between January 2016 and February 2019 and who had at least one month follow-up visit. Results: The mean patient age was 57.9 ± 14.6 years (range, 32-83 years). The choroidal tumor group included six choroidal metastases and four choroidal melanomas. The mean follow-up period after GKR was 7.0 ± 4.3 months (range, 2-13 months). The mean cumulative marginal dose was 25.36 ± 7.35 Gy (range, 16-45 Gy). Pre- and postoperative magnetic resonance imaging revealed a reduction in tumor volume in eight of the 10 eyes and five of them presented with improved visual symptoms. One patient showed increased tumor volume; however, a new choroidal lesion was not observed. Another patient showed no reduction in tumor size; however, the pain had worsened, and the eye was enucleated. The mean maximum tumor diameter decreased from 1.60 ± 0.37 cm before to 1.22 ± 0.47 cm after GKR (p = 0.004), and the mean minimum diameter decreased from 0.62 ± 0.27 cm before to 0.38 ± 0.35 cm after GKR (p = 0.031). No radiation-induced optic neuropathy, retinopathy, or cataracts was observed in any of the cases during the follow-up period. Conclusions GKR was shown to be safe for choroidal lesions identified in orbital magnetic resonance imaging with a reduction in the size of choroidal tumors and eyeball preservation expected with this treatment approach.

Purpose: To evaluate the effectiveness and safety of treating choroidal melanoma and cancer that has metastasized to the choroid with gamma knife radiosurgery (GKR). Methods: We performed a retrospective chart review that included 10 eyes of eight patients with a diagnosis of choroidal tumors who underwent GKR between January 2016 and February 2019 and who had at least one month follow-up visit. Results: The mean patient age was 57.9 ± 14.6 years (range, 32-83 years). The choroidal tumor group included six choroidal metastases and four choroidal melanomas. The mean follow-up period after GKR was 7.0 ± 4.3 months (range, 2-13 months). The mean cumulative marginal dose was 25.36 ± 7.35 Gy (range, 16-45 Gy). Pre- and postoperative magnetic resonance imaging revealed a reduction in tumor volume in eight of the 10 eyes and five of them presented with improved visual symptoms. One patient showed increased tumor volume; however, a new choroidal lesion was not observed. Another patient showed no reduction in tumor size; however, the pain had worsened, and the eye was enucleated. The mean maximum tumor diameter decreased from 1.60 ± 0.37 cm before to 1.22 ± 0.47 cm after GKR (p = 0.004), and the mean minimum diameter decreased from 0.62 ± 0.27 cm before to 0.38 ± 0.35 cm after GKR (p = 0.031). No radiation-induced optic neuropathy, retinopathy, or cataracts was observed in any of the cases during the follow-up period. Conclusions GKR was shown to be safe for choroidal lesions identified in orbital magnetic resonance imaging with a reduction in the size of choroidal tumors and eyeball preservation expected with this treatment approach.

Purpose: Data on the distribution and impact of panel reactive antibodies (PRA) and donor specific antibodies (DSA) before lung transplantation in Asia, especially multi-center-based data, are limited. This study evaluated the prevalence of and effects of PRA and DSA levels before lung transplantations on outcomes in Korean patients using nationwide multicenter registry data. Materials and Methods: This study included 103 patients who received a lung transplant at five tertiary hospitals in South Korea between March 2015 and December 2017. Mortality, primary graft dysfunction (PGD), and bronchiolitis obliterans syndrome (BOS) were evaluated. Results: Sixteen patients had class I and/or class II PRAs exceeding 50%. Ten patients (9.7%) had DSAs with a mean fluorescence intensity (MFI) higher than 1000, six of whom had antibodies with a high MFI (≥2000). DSAs with high MFIs were more frequently observed in patients with high-grade PGD (≥2) than in those with no or low-grade (≤1) PGD. In the 47 patients who survived for longer than 9 months and were evaluated for BOS after the transplant, BOS was not related to DSA or PRA levels. One-year mortality was more strongly related to PRA class I exceeding 50% than that under 50% (0% vs. 16.7%, p=0.007). Conclusion Preoperative DSAs and PRAs are related to worse outcomes after lung transplantation. DSAs and PRAs should be considered when selecting lung transplant recipients, and recipients who have preoperative DSAs with high MFI values and high PRA levels should be monitored closely after lung transplantation.

PURPOSE: We investigated the characteristics of lung allocation and outcomes of lung transplant (LTx) according to the Korean urgency status. MATERIALS AND METHODS: LTx registration in the Korean Organ Transplantation Registry (KOTRY) began in 2015. From 2015 to June 2017, 86 patients who received LTx were enrolled in KOTRY. After excluding one patient who received a heart-lung transplant, 85 were included. Subjects were analyzed according to the Korean urgency status. RESULTS: Except for Status 0, urgency status was classified based on partial pressure of oxygen in arterial blood gas analysis and functional status in 52 patients (93%). The wait time for lung allograft was well-stratified by urgency (Status 0, 46.5±59.2 days; Status 1, 104.4±98.2 days; Status 2 or 3, 132.2±118.4 days, p=0.009). Status 0 was associated with increased operative times and higher intraoperative blood transfusion. Status 0 was associated with prolonged extracorporeal membrane oxygenation use, postoperative bleeding, and longer mechanical ventilation after operation. Survival of Status 0 patients seemed worse than that of non-Status 0 patients, although differences were not significant. CONCLUSION: The Korean urgency classification for LTx is determined by using very limited parameters and may not be a true reflection of urgency. Status 0 patients seem to have poor outcomes compared to the other urgency status patients, despite having the highest priority for donor lungs. Further multi-center and nationwide studies are needed to revise the lung allocation system to reflect true urgency and provide the best benefit of lung transplantation.
Allografts ; Blood Gas Analysis ; Blood Transfusion ; Classification ; Extracorporeal Membrane Oxygenation ; Hemorrhage ; Humans ; Lung Transplantation ; Lung ; Operative Time ; Organ Transplantation ; Oxygen ; Partial Pressure ; Respiration, Artificial ; Tissue Donors ; Transplants

BACKGROUND: The ongoing Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) aims to observe the natural course of papillary thyroid microcarcinoma (PTMC), develop a protocol for active surveillance (AS), and compare the long-term prognosis, quality of life, and medical costs between the AS and immediate surgery groups. METHODS: This multicenter prospective cohort study of PTMC started in June 2016. The inclusion criteria were suspicious of malignancy or malignancy based on fine needle aspiration or core needle biopsy, age of ≥18 years, and a maximum diameter of ≤1 cm. If there was no major organ involvement, no lymph node/distant metastasis, and no variants with poor prognosis, the patients were explained of the pros and cons of immediate surgery and AS before selecting AS or immediate surgery. Follow-up visits (physical examination, ultrasonography, thyroid function, and questionnaires) are scheduled every 6 months during the first 2 years, and then every 1 year thereafter. Progression was defined as a maximum diameter increase of ≥3, ≥2 mm in two dimensions, suspected organ involvement, or lymph node/distant metastasis. RESULTS: Among 439 enrolled patients, 290 patients (66.1%) chose AS and 149 patients (33.9%) chose immediate surgery. The median follow-up was 6.7 months (range, 0.2 to 11.9). The immediate surgery group had a larger maximum tumor diameter, compared to the AS group (7.1±1.9 mm vs. 6.6±2.0 mm, respectively; P=0.014). CONCLUSION: The results will be useful for developing an appropriate PTMC treatment policy based on its natural course and risk factors for progression.
Biopsy, Fine-Needle ; Biopsy, Large-Core Needle ; Cohort Studies* ; Follow-Up Studies ; Humans ; Neoplasm Metastasis ; Prognosis ; Prospective Studies* ; Quality of Life ; Risk Factors ; Thyroid Gland* ; Thyroid Neoplasms ; Ultrasonography