Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients’ values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.

Purpose: The genetic attribution for pancreatic ductal adenocarcinoma (PDAC) has been reported as 5%-10%. However, the incidence of germline pathogenic variants (PVs) in Korean PDAC patients has not been thoroughly investigated. Therefore, we studied to identify the risk factors and prevalence of PV for future treatment strategies in PDAC. Materials and Methods: Total of 300 (155 male) patients with a median age of 65 years (range, 33 to 90 years) were enrolled in National Cancer Center in Korea. Cancer predisposition genes, clinicopathologic characteristics, and family history of cancer were analyzed. Results: PVs were detected in 20 patients (6.7%, median age 65) in ATM (n=7, 31.8%), BRCA1 (n=3, 13.6%), BRCA2 (n=3), and RAD51D (n=3). Each one patient showed TP53, PALB2, PMS2, RAD50, MSH3, and SPINK1 PV. Among them, two likely PVs were in ATM and RAD51D, respectively. Family history of various types of cancer including pancreatic cancer (n=4) were found in 12 patients. Three patients with ATM PVs and a patient with three germline PVs (BRCA2, MSH3, and RAD51D) had first-degree relatives with pancreatic cancer. Familial pancreatic cancer history and PVs detection had a significant association (4/20, 20% vs. 16/264, 5.7%; p=0.035). Conclusion Our study demonstrated that germline PVs in ATM, BRCA1, BRCA2, and RAD51D are most frequent in Korean PDAC patients and it is comparable to those of different ethnic groups. Although this study did not show guidelines for germline predisposition gene testing in patients with PDAC in Korea, it would be emphasized the need for germline testing for all PDAC patients.

Objective: The present study aimed to assess the relationship between incidental abnormalities on thoracic computed tomography (CT) and mortality in a general screening population using a long-term follow-up analysis. Materials and Methods: We retrospectively collected the medical records and CT images of 840 participants (mean age ± standard deviation [SD], 58.5 ± 6.7 years; 564 male) who underwent thoracic CT at a single health promotion center between 2007 and 2010. Two thoracic radiologists independently reviewed all CT images and evaluated any incidental abnormalities (interstitial lung abnormality [ILA], emphysema, coronary artery calcification [CAC], aortic valve [AV] calcification, and pulmonary nodules). Kaplan–Meier analysis with log-rank and z-tests was performed to assess the relationship between incidental CT abnormalities and all-cause mortality in the subsequent follow-up. Cox proportional hazards regression was performed to further identify risk factors of all-cause mortality among the incidental CT abnormalities and clinical factors. Results: Among the 840 participants, 55 (6%), 171 (20%), 288 (34%), 396 (47%), and 97 (11%) had findings of ILA, emphysema, CAC, pulmonary nodule, and AV calcification, respectively, on initial CT. The participants were followed up for a mean period ± SD of 10.9 ± 1.4 years. All incidental CT abnormalities were associated with all-cause mortality in univariable analysis (p < 0.05). However, multivariable analysis further revealed fibrotic ILA as an independent risk factor for all-cause mortality (hazard ratio, 2.52 [95% confidence interval, 1.02–6.22], p = 0.046). ILA were also identified as an independent risk factor for lung cancer or respiratory disease-related deaths. Conclusion Incidental abnormalities on screening thoracic CT were associated with increased mortality during the long-term follow-up. Among incidental CT abnormalities, fibrotic ILA were independently associated with increased mortality. Appropriate management and surveillance may be required for patients with fibrotic ILA on thoracic CT obtained for general screening purposes.

Purpose: Diagnostic classification models (DCMs) were developed to identify the mastery or non-mastery of the attributes required for solving test items, but their application has been limited to very low-level attributes, and the accuracy and consistency of high-level attributes using DCMs have rarely been reported compared with classical test theory (CTT) and item response theory models. This paper compared the accuracy of high-level attribute mastery between deterministic inputs, noisy “and” gate (DINA) and Rasch models, along with sub-scores based on CTT. Methods: First, a simulation study explored the effects of attribute length (number of items per attribute) and the correlations among attributes with respect to the accuracy of mastery. Second, a real-data study examined model and item fit and investigated the consistency of mastery for each attribute among the 3 models using the 2017 Korean Medical Licensing Examination with 360 items. Results: Accuracy of mastery increased with a higher number of items measuring each attribute across all conditions. The DINA model was more accurate than the CTT and Rasch models for attributes with high correlations (>0.5) and few items. In the real-data analysis, the DINA and Rasch models generally showed better item fits and appropriate model fit. The consistency of mastery between the Rasch and DINA models ranged from 0.541 to 0.633 and the correlations of person attribute scores between the Rasch and DINA models ranged from 0.579 to 0.786. Conclusion Although all 3 models provide a mastery decision for each examinee, the individual mastery profile using the DINA model provides more accurate decisions for attributes with high correlations than the CTT and Rasch models. The DINA model can also be directly applied to tests with complex structures, unlike the CTT and Rasch models, and it provides different diagnostic information from the CTT and Rasch models.

Purpose: To analyze the clinical manifestations of culture-proven infective keratitis patients over a recent 10-year period. Methods: We retrospectively reviewed the medical records of 956 cases of infective keratitis between January 2008 and December 2017 at eight tertiary hospitals. The study was performed to analyze the risk factors, causative microbial organisms, therapeutic outcomes, and prognosis. Results: The most common risk factor of keratitis was trauma (33.2%). Initial visual acuity (V/A) was finger count or less in 449 eyes (47.0%). The common location of keratitis was central, and the size was 4 mm2 or less. Hypopyon was observed in 295 eyes (30.9%). Of the 1,039 cultured isolates, 443 (42.6%) grew Gram-negative bacteria with the most common being Pseudomonas aeruginosa. The most prevalent Gram-positive bacteria was Staphylococcus epidermidis, and fungi was Fusarium species. Surgical treatments were performed in 201 eyes (21.0%), followed by amniotic membrane transplantation (66 eyes) and evisceration (44 eyes). Final V/A was 20/100 or more in 422 eyes (44.1%). Gram-positive organisms were highly susceptible to moxifloxacin and vancomycin, and Gram-negative organisms were highly susceptible to levofloxacin and ceftazidime. An increase in resistance to these antibiotics was detected for Enterococcus and Pseudomonas. Conclusions In South Korea, infective keratitis occurs frequently in eyes with trauma. Staphylococcus epidermidis, Pseudomonas aeruginosa, and Fusarium species are commonly identified etiologies of microbial keratitis. The appropriate administered medical and surgical treatments of suspected infectious keratitis can lead to visual improvement with particular care taken to minimize infection related to resistant bacteria and fungal microbes as needed. An initial V/A of 0.02 or less, the presence of hypopyon, age of 65 years or more, and a central lesion were associated with poor clinical outcome of bacterial keratitis. Age of 70 years or more was a significant risk factor for poor clinical outcome of fungal keratitis.

Purpose: Diagnostic classification models (DCMs) were developed to identify the mastery or non-mastery of the attributes required for solving test items, but their application has been limited to very low-level attributes, and the accuracy and consistency of high-level attributes using DCMs have rarely been reported compared with classical test theory (CTT) and item response theory models. This paper compared the accuracy of high-level attribute mastery between deterministic inputs, noisy “and” gate (DINA) and Rasch models, along with sub-scores based on CTT. Methods: First, a simulation study explored the effects of attribute length (number of items per attribute) and the correlations among attributes with respect to the accuracy of mastery. Second, a real-data study examined model and item fit and investigated the consistency of mastery for each attribute among the 3 models using the 2017 Korean Medical Licensing Examination with 360 items. Results: Accuracy of mastery increased with a higher number of items measuring each attribute across all conditions. The DINA model was more accurate than the CTT and Rasch models for attributes with high correlations (>0.5) and few items. In the real-data analysis, the DINA and Rasch models generally showed better item fits and appropriate model fit. The consistency of mastery between the Rasch and DINA models ranged from 0.541 to 0.633 and the correlations of person attribute scores between the Rasch and DINA models ranged from 0.579 to 0.786. Conclusion Although all 3 models provide a mastery decision for each examinee, the individual mastery profile using the DINA model provides more accurate decisions for attributes with high correlations than the CTT and Rasch models. The DINA model can also be directly applied to tests with complex structures, unlike the CTT and Rasch models, and it provides different diagnostic information from the CTT and Rasch models.

Purpose: To analyze the clinical manifestations of culture-proven infective keratitis patients over a recent 10-year period. Methods: We retrospectively reviewed the medical records of 956 cases of infective keratitis between January 2008 and December 2017 at eight tertiary hospitals. The study was performed to analyze the risk factors, causative microbial organisms, therapeutic outcomes, and prognosis. Results: The most common risk factor of keratitis was trauma (33.2%). Initial visual acuity (V/A) was finger count or less in 449 eyes (47.0%). The common location of keratitis was central, and the size was 4 mm2 or less. Hypopyon was observed in 295 eyes (30.9%). Of the 1,039 cultured isolates, 443 (42.6%) grew Gram-negative bacteria with the most common being Pseudomonas aeruginosa. The most prevalent Gram-positive bacteria was Staphylococcus epidermidis, and fungi was Fusarium species. Surgical treatments were performed in 201 eyes (21.0%), followed by amniotic membrane transplantation (66 eyes) and evisceration (44 eyes). Final V/A was 20/100 or more in 422 eyes (44.1%). Gram-positive organisms were highly susceptible to moxifloxacin and vancomycin, and Gram-negative organisms were highly susceptible to levofloxacin and ceftazidime. An increase in resistance to these antibiotics was detected for Enterococcus and Pseudomonas. Conclusions In South Korea, infective keratitis occurs frequently in eyes with trauma. Staphylococcus epidermidis, Pseudomonas aeruginosa, and Fusarium species are commonly identified etiologies of microbial keratitis. The appropriate administered medical and surgical treatments of suspected infectious keratitis can lead to visual improvement with particular care taken to minimize infection related to resistant bacteria and fungal microbes as needed. An initial V/A of 0.02 or less, the presence of hypopyon, age of 65 years or more, and a central lesion were associated with poor clinical outcome of bacterial keratitis. Age of 70 years or more was a significant risk factor for poor clinical outcome of fungal keratitis.

Background: The Korean Society of Thoracic Radiology (KSTR) recently constructed a nation-wide coronavirus disease 2019 (COVID-19) database and imaging repository, referred to the Korean imaging cohort of COVID-19 (KICC-19) based on the collaborative efforts of its members. The purpose of this study was to provide a summary of the clinico-epidemiological data and imaging data of the KICC-19. Methods: The KSTR members at 17 COVID-19 referral centers retrospectively collected imaging data and clinical information of consecutive patients with reverse transcription polymerase chain reaction-proven COVID-19 in respiratory specimens from February 2020 through May 2020 who underwent diagnostic chest computed tomography (CT) or radiograph in each participating hospital. Results: The cohort consisted of 239 men and 283 women (mean age, 52.3 years; age range, 11–97 years). Of the 522 subjects, 201 (38.5%) had an underlying disease. The most common symptoms were fever (n = 292) and cough (n = 245). The 151 patients (28.9%) had lymphocytopenia, 86 had (16.5%) thrombocytopenia, and 227 patients (43.5%) had an elevated CRP at admission. The 121 (23.4%) needed nasal oxygen therapy or mechanical ventilation (n = 38; 7.3%), and 49 patients (9.4%) were admitted to an intensive care unit.Although most patients had cured, 21 patients (4.0%) died. The 465 (89.1%) subjects underwent a low to standard-dose chest CT scan at least once during hospitalization, resulting in a total of 658 CT scans. The 497 subjects (95.2%) underwent chest radiography at least once during hospitalization, which resulted in a total of 1,475 chest radiographs. Conclusion The KICC-19 was successfully established and comprised of 658 CT scans and 1,475 chest radiographs of 522 hospitalized Korean COVID-19 patients. The KICC-19 will provide a more comprehensive understanding of the clinical, epidemiological, and radiologic characteristics of patients with COVID-19.