Su Young Kim, Yeon Seo Cho, Hyun-Soo Kim, Jung Kuk Lee, Hee Man Kim, Hong Jun Park, Hyunil Kim, Jihoon Kim, and Dae Ryong Kang. Gut and Liver 2022;16:555-66. https://doi.org/10.5009/gnl210190

Objective: Signet-ring cell carcinoma (SRCC) is a rare histopathological subtype of colorectal cancer (CRC) constituting approximately 1% of CRC cases. This study analyzed the incidence and survival rates of colorectal SRCC. Methods: We analyzed the incidence and survival rates of colorectal SRCCs based on patients’ data of the Korea Central Cancer Registry. Results: The age-standardized incidence rates of colon and rectum SRCC in 2017 were 0.17 and 0.07 individuals per 100,000, respectively. Between 1993 and 2017, the 1-, 2-, 3-, 4-, and 5-year relative survival rates of patients with colon SRCC were 65.6%, 49.0%, 38.9%, 34.9%, and 33.0%, respectively, while those of patients with rectum SRCC were 69.6%, 47.8%, 38.5%, 32.8%, and 29.4%, respectively. According to the Surveillance, Epidemiology, and End Results summary stages, the 5-year relative survival rates of colon SRCC between 1993 and 2017 were 70.4% for the localized stage, 41.0% for the regional stage, and 7.0% for the distant stage, while those for rectum SRCC were 60.7%, 34.4, and 3.3%, respectively. Conclusions: Although the incidence of colorectal SRCC is extremely low in South Korea, it has been increasing in recent decades. As the prognosis of colorectal SRCC is extremely poor; clinicians should be aware of the differential diagnosis of SRCC in colorectal cancer cases.

We investigated the risk of colorectal cancer (CRC) in patients with Crohn’s disease (CD) using the claims data of the Korean National Health Insurance during 2006–2015. The data of 13,739 and 40,495 individuals with and without CD, respectively, were analyzed. Hazard ratios (HRs) were calculated using multivariate Cox proportional hazard regression tests. CRC developed in 25 patients (0.18%) and 42 patients (0.1%) of the CD and non-CD groups, respectively. The HR of CRC in the CD group was 2.07 (95% confidence interval (CI), 1.25–3.41). The HRs of CRC among men and women were 2.02 (95% CI 1.06–3.87) and 2.10 (95% CI, 0.96–4.62), respectively. The HRs of CRC in the age groups 0–19, 20–39, 40–59, and ≥60 years were 0.07, 4.86, 2.32, and 0.66, respectively. The HR of patients with late-onset CD (≥40 years) was significantly higher than that of those with early-onset CD (<40 years). CD patients were highly likely to develop CRC. Early-onset CD patients were significantly associated with an increased risk of CRC than matched individuals without CD. However, among CD patients, late-onset CD was significantly associated with an increased risk of CRC.

Lymphoepithelial carcinoma of the stomach (LEGC) is a rare type of gastric carcinoma. There is a limited understanding of the incidence and survival rates of LEGC. The aim was to investigate the nationwide incidence and survival rates of LEGC in Korea using the Korea Central Cancer Registry. The data on LEGC were retrieved from the Korea Central Cancer Registry of Korean Cancer Center. The age and sex of the patients and the Surveillance, Epidemiology, and End Results (SEER) summary stage of the tumor were analyzed, and the relative survival rates (RSRs) were calculated. The Korea Central Cancer Registry has data of patients with LEGC from 1993 to 2017 but is approved to use personal information only from 2006 to 2017 due to privacy restrictions of the institute. The RSRs, as calculated data, were able to be disclosed from 1993 to 2017. Between 2006 and 2017, the total number of LEGC was 1,030, and the trend of incidence increased ty time (p = .002). In the SEER stage, the proportion of localized stage was 54.3% in 2006, and 73.9% in 2017, which increased from 2006 to 2017 significantly (p = .002). The RSR was higher in men than in women. The cumulative 5-year RSRs were 98.0% in the localized stage and 88.0% in the regional stage during 1993–2017. The 5-year RSRs increased 79.5% in 1996–2000 to 93.4% in 2013–2017. The incidence of LEGC is low, which has been increasing in recent years in South Korea. The prognosis of LEGC is good even at advanced stages and gets better as time goes by. Our findings provide useful insights to clinicians about LEGC and inform patients about the survival rate.

We assessed the risk of colorectal cancer (CRC) in patients with ulcerative colitis (UC) using the nationwide population-based claims data. We analyzed the claims data of the Korean National Health Insurance (2006–2015). UC and CRC were defined using ICD-10 codes and UC-specific prescriptions in this study. Age- and sex-matched individuals without UC were randomly selected from the general population. Hazard ratios (HRs), adjusted for different covariates, were calculated using multivariate Cox proportional hazard regression. In total, 30,546 and 88,829 individuals with and without UC, respectively, were enrolled. CRC developed in 85 (0.27%) among UC, and 340 (0.38%) among individuals without UC, respectively. The HR (95% confidence interval [CI]) of CRC in all UC patients was 0.74 (0.58–0.94). Further, UC patients were stratified according to sex (male vs. female: 0.60 [0.44–0.82] vs. 1.10 [0.75–1.61]) and age (HR = 14.37, 2.74, 0.58, and 0.70 for 0–19, 20–39, 40–59, and ≥60 years, respectively). HR was significantly higher for late-onset UC (≥60 years) than for early-onset UC (0–19 years). The long duration of 5-aminosalicylic acid use had a significantly low HR, with reference to the 1st quartile. The risk of CRC varies with age and sex in Korean patients with UC during the first decade after diagnosis. Early-onset UC (<40 years) increases the CRC risk.

Background: Few studies have investigated the risk of gastric cancer (GC) in ulcerative colitis (UC), and the results have been inconsistent. This study aimed to assess the risk of gastric cancer in newly diagnosed UC patients. Methods: Based on claims data from Korean National Health Insurance from January 2006 to December 2015, we identified 30,546 patients with UC and randomly selected 88,829 non-UC individuals as controls, who were matched by age and sex. Multivariate Cox proportional hazards regression was used to calculate adjusted hazard ratios (HRs) for gastric cancer events, with covariates taken into account. Results: During the study period, a total of 77 (0.25%) patients with UC and 383 (0.43%) non-UC individuals were diagnosed with GC. After multivariable adjustment, the HR for GC was 0.60 (95% CI: 0.47–0.77) in patients with UC, using non-UC individuals as the reference group. When stratified by age, the adjusted HRs for GC in UC patients were 0.19 (95% CI: 0.04–0.98) for those aged 20–39 years at the time of UC diagnosis, 0.65 (95% CI: 0.45–0.94) for 40–59, and 0.60 (95% CI: 0.49–0.80) for ≥60 as compared to non-UC individuals in the corresponding age groups. When stratified by sex, the adjusted HR for GC was 0.54 (95% CI: 0.41–0.73) in male UC patients of all ages. Within UC patients, a multivariable analysis revealed that the HR for GC was 12.34 (95% CI: 2.23–68.16) for those aged ≥ 60 years at the time of diagnosis of UC. Conclusions: Patients with UC had a decreased GC risk compared with non-UC individuals in South Korea. Within the UC population, advancing age (≥60 years) was identified as a significant risk factor for GC.