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.

Background: A decline in masticatory function may indicate brain dysfunction related to dementia, but the relationship between masticatory function and dementia risk remains unclear. This study aimed to investigate whether masticatory function is associated with the risk of cognitive decline and dementia. Methods: Data were obtained from the nationwide prospective cohort study of randomly sampled community-dwelling Koreans aged ≥ 60 years. The 5,064 non-demented participants, whose number of chewing cycles per bite was assessed by clinical interview, were followed for 8 years with biennial assessments of cognitive performance and clinical diagnoses of all-cause dementia and Alzheimer’s disease (AD). Structural brain magnetic resonance imaging was collected from a subset of cohort participants and their spouses for imaging analyses. Results: Males who chewed ≥ 30 cycles/bite had faster decline in global cognition and memory function and were at higher risk for incident all-cause dementia (hazard ratio [HR], 2.91; 95% confidence interval [CI], 1.18–7.18) and AD (HR, 3.22; 95% CI, 1.14–9.11) compared to males with less than 10 cycles/bite. Additionally, increased chewing cycles in males were associated with reduced brain volume, particularly in regions involved in compensatory cognitive control of mastication. There was no significant association between chewing cycles and the risk of dementia or brain volume in females. Conclusion Older men who frequently chew their meals could be considered a notable population at risk for dementia who should be carefully assessed for their cognitive trajectories.

Objective: To investigate the relationship between reduced glutathione (GSH), a key molecule of the antioxidant defense system in the blood, and glutathione reductase (GR), which reduces oxidized glutathione (glutathione disulfide [GSSG]) to GSH and maintains the redox balance, with the prevalence of Alzheimer’s dementia and cognitive decline. Methods: In all, 20 participants with Alzheimer’s dementia who completed the third follow-up clinical evaluation over 6 years were selected, and 20 participants with normal cognition were selected after age and sex matching. The GSH and GR concentrations were the independent variables. Clinical diagnosis and neurocognitive test scores were the dependent variables indicating cognitive status. Results: The higher the level of GR, the greater the possibility of having normal cognition than of developing Alzheimer’s dementia. Additionally, the higher the level of GR, the higher the neurocognitive test scores. However, this association was not significant for GSH. After 6 years, the conversion rate from normal cognition to cognitive impairment was significantly higher in the lower 50th percentile of the GR group than in the upper 50th percentile. Conclusion The higher the GR, the lower the prevalence of Alzheimer’s dementia and incidence of cognitive impairment and the higher the cognitive test scores. Therefore, GR is a potential protective biomarker against Alzheimer’s dementia and cognitive decline.

Background: Pyomyositis (PM) is a serious soft tissue infection and despite its clinical importance, previous studies have not been able to fully determine the clinical characteristics and microbial epidemiology of PM in Korea, which we therefore aimed to investigate. Materials and Methods: We retrospectively identified 140 adult patients diagnosed with PM from 13 general hospitals between January 2012 and December 2015. We analyzed the clinical and microbial characteristics of community-onset PM and compared them with communityacquired (CA) and healthcare-associated (HCA) PM. Results: One hundred eleven organisms were isolated from 96 (68.6%) patients with PM.Staphylococcus aureus (38 patients) was the most common pathogen, followed by streptococci (24 patients), and enteric Gram-negative organisms (27 patients). Methicillin-resistant S.aureus (MRSA) was identified in four (2.9%) patients and in-hospital mortality reached 8.6% (12/140). Enterococci isolates were identified in the HCA PM subgroup only The proportion of MRSA isolates was not comparable between CA and HCA PM subgroups. In the 83 patients with PM infected by monomicrobial pathogens, isolates of Gram-negative organisms were more commonly found in HCA PM subgroup than in CA PM subgroup (47.6% [10/21] of patients with HCA PM vs. 20.7% [12/58] of patients with CA PM; P = 0.01). Conclusion Gram-positive cocci such as S. aureus and streptococci were dominant etiologies in community-onset PM, whereas MRSA appears to an uncommon causative organism of PM in Korea. Enteric Gram-negative organisms should also be considered as major etiologies, especially in HCA PM patient population in Korea.

Purpose: This study sought to compare clinical outcomes between transcatheter aortic valve replacement (TAVR) and sutureless aortic valve replacement (SU-AVR). Materials and Methods: In total, 320 patients with symptomatic severe aortic stenosis who underwent TAVR (n=254) or SU-AVR (n=66) at Severance Cardiovascular Hospital between July 2011 and September 2019 were included for analysis. Propensity score matching and inverse probability weighted adjustment were performed to adjust for confounding baseline characteristics. Outcomes defined by the Valve Academic Research Consortium-2 in 62 patients pairs were compared. Results: Device success (79.0% vs. 79.0%, p>0.999) and 30-day mortality (4.8% vs. 0.0%, p=0.244) did not differ between the TAVR and SU-AVR groups. The TAVR group developed more frequent mild or moderate paravalvular leakage (59.7% vs. 8.1%, p<0.001), whereas SU-AVR was associated with higher rates of major or life-threatening bleeding (9.7% vs. 22.6%, p=0.040), acute kidney injury (8.1% vs. 21.0%, p=0.041), and new-onset atrial fibrillation (4.8% vs. 32.3%. p<0.001) at 30 days, along with longer stays in the intensive care unit (ICU) (1.9±1.6 days vs. 5.9±9.2 days, p=0.009) and hospital (7.1±7.9 days vs. 13.1±8.8 days, p<0.001). The TAVR group showed a trend towards a higher 1-year all-cause mortality, compared with the SU-AVR group (7.0% vs 1.7%, p=0.149). Cardiovascular mortality, however, did not differ significantly (1.6% vs 1.7%, p=0.960). Conclusion TAVR achieved a similar 1-year survival rate free from cardiovascular mortality as SU-AVR and was associated with a lower incidence of complications, except for paravalvular leakage, and shorter stays in the ICU and hospital.

Background: Pyomyositis (PM) is a serious soft tissue infection and despite its clinical importance, previous studies have not been able to fully determine the clinical characteristics and microbial epidemiology of PM in Korea, which we therefore aimed to investigate. Materials and Methods: We retrospectively identified 140 adult patients diagnosed with PM from 13 general hospitals between January 2012 and December 2015. We analyzed the clinical and microbial characteristics of community-onset PM and compared them with communityacquired (CA) and healthcare-associated (HCA) PM. Results: One hundred eleven organisms were isolated from 96 (68.6%) patients with PM.Staphylococcus aureus (38 patients) was the most common pathogen, followed by streptococci (24 patients), and enteric Gram-negative organisms (27 patients). Methicillin-resistant S.aureus (MRSA) was identified in four (2.9%) patients and in-hospital mortality reached 8.6% (12/140). Enterococci isolates were identified in the HCA PM subgroup only The proportion of MRSA isolates was not comparable between CA and HCA PM subgroups. In the 83 patients with PM infected by monomicrobial pathogens, isolates of Gram-negative organisms were more commonly found in HCA PM subgroup than in CA PM subgroup (47.6% [10/21] of patients with HCA PM vs. 20.7% [12/58] of patients with CA PM; P = 0.01). Conclusion Gram-positive cocci such as S. aureus and streptococci were dominant etiologies in community-onset PM, whereas MRSA appears to an uncommon causative organism of PM in Korea. Enteric Gram-negative organisms should also be considered as major etiologies, especially in HCA PM patient population in Korea.

Purpose: This study sought to compare clinical outcomes between transcatheter aortic valve replacement (TAVR) and sutureless aortic valve replacement (SU-AVR). Materials and Methods: In total, 320 patients with symptomatic severe aortic stenosis who underwent TAVR (n=254) or SU-AVR (n=66) at Severance Cardiovascular Hospital between July 2011 and September 2019 were included for analysis. Propensity score matching and inverse probability weighted adjustment were performed to adjust for confounding baseline characteristics. Outcomes defined by the Valve Academic Research Consortium-2 in 62 patients pairs were compared. Results: Device success (79.0% vs. 79.0%, p>0.999) and 30-day mortality (4.8% vs. 0.0%, p=0.244) did not differ between the TAVR and SU-AVR groups. The TAVR group developed more frequent mild or moderate paravalvular leakage (59.7% vs. 8.1%, p<0.001), whereas SU-AVR was associated with higher rates of major or life-threatening bleeding (9.7% vs. 22.6%, p=0.040), acute kidney injury (8.1% vs. 21.0%, p=0.041), and new-onset atrial fibrillation (4.8% vs. 32.3%. p<0.001) at 30 days, along with longer stays in the intensive care unit (ICU) (1.9±1.6 days vs. 5.9±9.2 days, p=0.009) and hospital (7.1±7.9 days vs. 13.1±8.8 days, p<0.001). The TAVR group showed a trend towards a higher 1-year all-cause mortality, compared with the SU-AVR group (7.0% vs 1.7%, p=0.149). Cardiovascular mortality, however, did not differ significantly (1.6% vs 1.7%, p=0.960). Conclusion TAVR achieved a similar 1-year survival rate free from cardiovascular mortality as SU-AVR and was associated with a lower incidence of complications, except for paravalvular leakage, and shorter stays in the ICU and hospital.

Objective: This study estimated the incidence of driving-related adverse events and examined the association of cognitive function with the risk of future driving-related adverse events in the elderly Korean male population. Methods: We analyzed 1,172 male drivers aged 60 years or older in the Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD). Using the data from Korean National Police Agency, we classified the participants into three groups: safe driving (drove for 2 years after baseline without a traffic accident or repeated violations), driving cessation (stopped driving), and risky driving (one or more traffic accidents or repeated violations). We estimated the incidences of driving cessation and risky driving, and examined the effect of cognitive function on their risks. Results: The incidence of driving cessation and risky driving in the Korean male drivers aged 60 years or older was 19.3 and 69.9 per 1,000 person-years respectively and increased in the late 80s. Drivers with better baseline Word List Memory Test scores showed less risky driving (OR=0.94, p=0.039). Conclusion Driving-related adverse events increased in late 80s, and better memory function was protective against these events.