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: Optimal treatment for stage IIIA/N2 non–small cell lung cancer (NSCLC) is controversial. We aimed to assess the efficacy and safety of adjuvant pembrolizumab for stage IIIA/N2 NSCLC completely resected after neoadjuvant concurrent chemoradiation therapy (CCRT). Materials and Methods: In this open-label, single-center, single-arm phase 2 trial, patients with stage IIIA/N2 NSCLC received adjuvant pembrolizumab for up to 2 years after complete resection following neoadjuvant CCRT. The primary endpoint was disease-free survival (DFS). Secondary endpoints included overall survival (OS) and safety. As an exploratory biomarker analysis, we evaluated the proliferative response of blood CD39+PD-1+CD8+ T cells using fold changes in the percentage of proliferating Ki-67+ cells from days 1 to 7 of cycle 1 (Ki-67D7/D1). Results: Between October 2017 and October 2018, 37 patients were enrolled. Twelve (32%) and three (8%) patients harbored EGFR and ALK alterations, respectively. Of 34 patients with programmed cell death ligand 1 assessment, 21 (62%), nine (26%), and four (12%) had a tumor proportion score of < 1%, 1%-50%, and ≥ 50%, respectively. The median follow-up was 71 months. The median DFS was 22.4 months in the overall population, with a 5-year DFS rate of 29%. The OS rate was 86% at 2 years and 76% at 5 years. Patients with tumor recurrence within 6 months had a significantly lower Ki-67D7/D1 among CD39+PD-1+CD8+ T cells than those without (p=0.036). No new safety signals were identified. Conclusion Adjuvant pembrolizumab may offer durable disease control in a subset of stage IIIA/N2 NSCLC patients after neoadjuvant CCRT and surgery.

Background and Objectives: Early diastolic mitral annular tissue (e’) velocity is a commonly used marker of left ventricular (LV) diastolic function. This study aimed to investigate the prognostic implications of e’ velocity in patients with mitral regurgitation (MR). Methods: This retrospective cohort study included 1,536 consecutive patients aged <65 years with moderate or severe chronic primary MR diagnosed between 2009 and 2018. The primary and secondary outcomes were all-cause and cardiovascular mortality, respectively.According to the current guidelines, the cut-off value of e’ velocity was defined as 7 cm/s. Results: A total of 404 individuals were enrolled (median age, 51.0 years; 64.1% male; 47.8% severe MR). During a median 6.0-year follow-up, there were 40 all-cause mortality and 16 cardiovascular deaths. Multivariate analysis revealed a significant association between e’ velocity and all-cause death (adjusted hazard ratio [aHR], 0.770; 95% confidence interval [CI], 0.634–0.935; p=0.008) and cardiovascular death (aHR, 0.690; 95% CI, 0.477–0.998;p=0.049). Abnormal e’ velocity (≤7 cm/s) independently predicted all-cause death (aHR, 2.467; 95% CI, 1.170–5.200; p=0.018) and cardiovascular death (aHR, 5.021; 95% CI, 1.189–21.211; p=0.028), regardless of symptoms, LV dimension and ejection fraction. Subgroup analysis according to sex, MR severity, mitral valve replacement/repair, and symptoms, showed no significant interactions. Including e’ velocity in the 10-year risk score improved reclassification for mortality (net reclassification improvement [NRI], 0.154; 95% CI, 0.308– 0.910; p<0.001) and cardiovascular death (NRI, 1.018; 95% CI, 0.680–1.356; p<0.001). Conclusions In patients aged <65 years with primary MR, e’ velocity served as an independent predictor of all-cause and cardiovascular deaths.

Purpose: The activity and safety of neoadjuvant nivolumab plus gemcitabine/cisplatin (N+GC) were tested in patients with muscle-invasive bladder urothelial carcinoma (MIBC). Materials and Methods: In a prospective phase II trial, patients with cT2-T4a N0 MIBC who were eligible for cisplatin and medically appropriate to undergo radical cystectomy (RC) were enrolled. Treatment with nivolumab 3 mg/kg on days 1 and 15 plus GC (cisplatin 70 mg/m2 on day 1, and gemcitabine 1,000 mg/m2 on days 1, 8, and 15) was repeated every 28 days up to 3 or 4 cycles, depending on the surgery schedules. The primary endpoint was pathologic complete response (pCR, ypT0). Secondary endpoints included pathologic downstaging (≤ ypT1), disease-free survival (DFS), and safety. Results: Between September 2019 and October 2020, 51 patients were enrolled. Neoadjuvant N+GC was well tolerated. Among 49 patients who completed neoadjuvant N+GC, clinical complete response (cCR) was achieved in 59% of intent-to-treat (ITT) population. RC was performed in 34 (69%) patients. pCR was achieved in 24% (12/49) of ITT population and 35% (12/34) of RC patients. Median DFS was not reached. Over a median follow-up of 24 months, 12 patients experienced disease recurrence and were treated with palliative therapy or surgery. Although 12 patients declined surgery and were treated with concurrent chemoradiotherapy, DFS was longer in patients with cCR after neoadjuvant therapy than those without. Preoperative programmed death-ligand 1 (PD-L1) did not correlate with pCR or pathologic downstaging rates. Conclusion Neoadjuvant N+GC was feasible and provided meaningful pathologic responses in patients with MIBC, regardless of baseline PD-L1 expression (ONO-4538-X41; CRIS.nih.go.kr, KCT0003804).

Background/Aims: A comprehensive analysis of trends in the incidence of hepatocellular carcinoma (HCC) is important for planning public health initiatives. We aimed to analyze the trends in HCC incidence in South Korea over 10 years and to predict the incidence for the year 2028. Methods: Data from patients with newly diagnosed HCC between 2008 and 2018 were obtained from Korean National Health Insurance Service database. Age-standardized incidence rates (ASRs) were calculated to compare HCC incidence. A poisson regression model was used to predict the future incidence of HCC. Results: The average crude incidence rate (CR) was 22.4 per 100,000 person-years, and the average ASR was 17.6 per 100,000 person-years between 2008 and 2018. The CR (from 23.9 to 21.2 per 100,000 person-years) and ASR (from 21.9 to 14.3 per 100,000 person-years) of HCC incidence decreased during the past ten years in all age groups, except in the elderly. The ASR of patients aged ≥80 years increased significantly (from 70.0 to 160.2/100,000 person-years; average annual percent change, +9.00%; P<0.001). The estimated CR (17.9 per 100,000 person-years) and ASR (9.7 per 100,000 person-years) of HCC incidence in 2028 was declined, but the number of HCC patients aged ≥80 years in 2028 will be quadruple greater than the number of HCC patients in 2008 (from 521 to 2,055), comprising 21.3% of all HCC patients in 2028. Conclusions The ASRs of HCC in Korea have gradually declined over the past 10 years, but the number, CR, and ASR are increasing in patients aged ≥80 years.

Background: This longitudinal study examined risk factors for future suicidality among North Korean defectors (NKDs) living in South Korea. Methods: The subjects were 300 NKDs registered with a regional adaptation center (the Hana Center) in South Korea. Face-to-face interviews were conducted using the North Korean version of the World Health Organization’s Composite International Diagnostic Interview to diagnose mental disorders according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Subjects were also asked about sociodemographic and clinical factors at baseline. At follow-up after three years, the NKDs (n = 172 respondents) were asked to participate in an online survey, responding to self-questionnaires about suicidality. Logistic regression analyses were used to explore associations between baseline variables and future suicidality among NKDs. Results: Thirty (17.4%) of the 172 survey respondents reported suicidality at follow-up. The presence of health problems over the past year, any prior suicidality at baseline, a higher score on a trauma-related scale, and a lower score on a resilience scale at baseline were associated with greater odds of suicidality at follow-up after adjusting for age, sex, and educational level. Of all mental disorder categories, major depressive disorder, dysthymia, agoraphobia, and social phobia were also associated with significantly increased odds of suicidality at follow-up after adjusting for age, sex, educational level, and prior suicidality at baseline. Conclusion Resilience, a previous history of suicidality, and the presence of lifetime depressive disorder and anxiety disorder should be given consideration in mental health support and suicide prevention in NKDs.

Objective: The coronavirus disease 2019 (COVID-19) outbreak is currently ravaging the world and is a major threat to public health. Healthcare workers (HCWs) are at a high risk of acquiring and transmitting COVID-19. Hence, HCWs are also experiencing emotional and behavioral changes. The purpose of this study was to compare emotional changes and stress between occupations and to investigate the impact of emotions of HCWs during the COVID-19 outbreak. Methods: An anonymous, self-administered, previously validated questionnaire was given to HCWs at a hospital dedicated to infectious diseases in Korea during the COVID-19 outbreak. The participants were asked to evaluate stress factors, depressive moods, trauma, reasons for continuing to work, things that helped them work, coping strategies to reduce stress, motivators that could help them work during future outbreaks, and what they would like to do after the outbreak was over. Results: The total number of participants was 400. The average age of participants was 34.69±9.44. Stress and depressive moods showed variations in the job-to-job comparisons. Ethical duty and the professionalism of the HCWs pushed them to continue with their jobs. The news of a decline in the number of patients was helpful to HCWs. The implementation of personal hygiene programs helped in reducing stress. The provision of adequate personal protective equipment was a factor that would encourage them to work during any future outbreak. The participants wanted to go on a trip after the outbreak was over. Conclusion Our findings indicate that the COVID-19 outbreak had a significant emotional impact on HCWs. The concerns of HCWs may affect their work efficiency in an outbreak and should be addressed by incorporating appropriate management strategies while planning to combat an outbreak.

Purpose: Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a high-grade lung neuroendocrine tumor with a poor prognosis, similar to small cell lung cancer (SCLC). However, it remains unclear whether to treat LCNEC as non-small-cell lung cancer (NSCLC) or as SCLC. We reviewed our experiences to suggest appropriate treatment strategy for resected pulmonary LCNEC. Materials and Methods: Forty-four patients were treated for pathologically diagnosed pulmonary LCNEC during 2005‒2018. We considered curative surgery first in early-stage or some locally advanced tumors, unless medically inoperable. Adjuvant treatments were decided considering patient’s clinical and pathological features. After excluding two stage I tumors with radiotherapy alone and three stage III tumors with upfront chemotherapy, we analyzed 39 patients with stage I‒III pulmonary LCNEC, who underwent curative resection first. Results: Adjuvant chemotherapy (NSCLC-based 91%, SCLC-based 9%) was performed in 62%, and adjuvant radiotherapy was done in three patients for pN2 or positive margin. None received prophylactic cranial irradiation (PCI). With a median follow-up of 30 months, the 2- and 5-year overall survival (OS) rates were 68% and 51%, and the 2- and 5-year recurrence-free survival (RFS) rates were 49% and 43%, respectively. Aged ≥67 years and SCLC-mixed pathology were significant poor prognostic factors for OS or RFS (p < 0.05). Among 17 recurrences, regional failures were most common (n = 6), and there were five brain metastases. Conclusions Surgery and adjuvant treatment (without PCI) could achieve favorable outcomes in pulmonary LCNEC, which was more similar to NSCLC, although some factors worsened the prognosis. The importance of intensified adjuvant therapies with multidisciplinary approach remains high.

Objective: The coronavirus disease 2019 (COVID-19) outbreak is currently ravaging the world and is a major threat to public health. Healthcare workers (HCWs) are at a high risk of acquiring and transmitting COVID-19. Hence, HCWs are also experiencing emotional and behavioral changes. The purpose of this study was to compare emotional changes and stress between occupations and to investigate the impact of emotions of HCWs during the COVID-19 outbreak. Methods: An anonymous, self-administered, previously validated questionnaire was given to HCWs at a hospital dedicated to infectious diseases in Korea during the COVID-19 outbreak. The participants were asked to evaluate stress factors, depressive moods, trauma, reasons for continuing to work, things that helped them work, coping strategies to reduce stress, motivators that could help them work during future outbreaks, and what they would like to do after the outbreak was over. Results: The total number of participants was 400. The average age of participants was 34.69±9.44. Stress and depressive moods showed variations in the job-to-job comparisons. Ethical duty and the professionalism of the HCWs pushed them to continue with their jobs. The news of a decline in the number of patients was helpful to HCWs. The implementation of personal hygiene programs helped in reducing stress. The provision of adequate personal protective equipment was a factor that would encourage them to work during any future outbreak. The participants wanted to go on a trip after the outbreak was over. Conclusion Our findings indicate that the COVID-19 outbreak had a significant emotional impact on HCWs. The concerns of HCWs may affect their work efficiency in an outbreak and should be addressed by incorporating appropriate management strategies while planning to combat an outbreak.

Purpose: This study aimed to construct a database of the effective doses (ED) from F-18 fluorodeoxyglucose (FDG) torso positron emission tomography/computed tomography (PET/CT) in Korea to provide data that supports the reduction of the CT dose of PET/CT and optimization of PET/CT protocols in Korea. Methods: We investigated data of ED and CT parameters of FDG PET/CT. The data were analyzed by body weight groups. Results: A total of 31 hospitals participated in the survey (99 adults). The mean total EDs (± SD) were 8.77 ± 2.76, 10.93 ± 3.14, and 12.57 ± 3.79 mSv for the 55-, 70-, and 85-kg groups, respectively. The FDG EDs were 4.80 ± 0.98, 6.05 ± 1.15, and 6.89 ± 1.52 mSv, and the CT EDs were 4.00 ± 2.12, 4.88 ± 2.51, and 5.68 ± 2.89 mSv, respectively. Of the enrolled hospitals, 54.5% used ultra-low-dose CT protocols, and their CT ED was significantly lower than low-dose CT group in all groups (2.9 ± 1.0, 3.2 ± 1.1, and 3.3 ± 1.0 mSv vs. 6.6 ± 1.6, 7.2 ± 2.1, and 7.9 ± 2.2 mSv, all p < 0.001, respectively). In the ultra-low-dose CT group, the CT ED with the iterative reconstruction was significantly lower than that of CT without iterative reconstruction in the 55-kg group (2.4 ± 0.9 vs. 3.3 ± 0.9, p = 0.04). Conclusions These results and current recommendations can be helpful for optimizing PET/CT diagnostic reference level (DRL) and reducing unnecessary PET/CT radiation exposure.