2.Epidemiology of Gastric Cancer in Korea (1999–2022): Incidence, Survival, and 5-Year Conditional Relative Survival
Ki Bum PARK ; Mee Joo KANG ; Johyun HA ; Eun Hye PARK ; E Hwa YUN ; Hye-Jin KIM ; Kyu-Won JUNG ; Han Hong LEE
Journal of Gastric Cancer 2026;26(1):4-15
Purpose:
This study evaluated long-term trends in gastric cancer epidemiology and survival with a focus on conditional relative survival (CRS).
Materials and Methods:
Using the Korea Central Cancer Registry, we analyzed 665,184 patients who were newly diagnosed with gastric cancer between 1999 and 2022.The study period was divided into four intervals: Period I (1999–2005), Period II (2006–2011), Period III (2012–2017), and Period IV (2018–2022). Temporal trends in the incidence and mortality were assessed using crude and age-standardized rates. Relative survival was estimated using the Ederer II method, and the 5-year CRS was calculated according to the survival duration after diagnosis.
Results:
The incidence of gastric cancer increased until 2011 and subsequently declined, with a marked decrease observed in 2020. Individuals aged ≥70 years consistently had the highest incidence rates. Mortality rates showed a sustained decline throughout the study period. The overall 5-year relative survival improved from 69.8% in Period II to 78.4% in Period IV. The 5-year CRS increased from 86.1% at 1 year after diagnosis to 96.3% at 5 years.Patients with localized stage maintained a 5-year CRS above 95% at 1 year after diagnosis, whereas those with regional and distant stages showed 5-year CRS that consistently remained below 95%.
Conclusions
The incidence and mortality rates of gastric cancer in Korea have declined over the past two decades, accompanied by improved survival outcomes. The CRS analysis suggests that long-term follow-up is warranted, with the optimal duration varying according to patient characteristics.
3.Topographic Progression of Geographic Atrophy and Visual Acuity in Nonexudative Age-Related Macular Degeneration
Jun Kyu LEE ; Junwoo LEE ; Jong Beom PARK ; Kiyoung KIM ; Seung-Young YU
Korean Journal of Ophthalmology 2026;40(1):1-11
Purpose:
To investigate long-term topographic progression of the geographic atrophy (GA) area based on location and analyze its correlation with visual acuity in patient with GA secondary to non-neovascular age-related macular degeneration in South Korean patient cohort.
Methods:
Medical records and imaging data of 58 eyes from 34 patients with GA were retrospectively reviewed using fundus autofluorescence (FAF). Regions of interest were defined as concentric ring-shaped zones with diameters of 1, 2, 3, and 4 mm centered on the fovea (zones 0–3), each subdivided into superior, temporal, inferior, and nasal sectors. The foveal center was determined using optical coherence tomography, and sectoral GA areas were measured on FAF with the semiautomated software (RegionFinder ver. 2.6.2.0). Correlations among GA area enlargement, GA growth rate, and changes in best-corrected visual acuity (BCVA) were evaluated.
Results:
The mean GA area enlarged from 4.10 to 16.57 mm2 and mean BCVA decreased from 0.34 to 1.06 logMAR at 5 years of follow-up. The mean overall GA area growth rate was 1.96 mm2/yr. During yearly follow-up from baseline to 5 years, there were significant differences in GA growth rate of zone 3 inferior (p < 0.005). The GA area changes of zone 3 inferior was significantly correlated with BCVA. In the subgroup with BCVA decreased under 1.0 logMAR during follow-up, there was a higher growth rate in zone 2 nasal sector, 2 to 3 years before.
Conclusions
The overall GA growth rate was 1.96 mm2/yr in the 5-year follow-up of our cohort. Changes in the GA growth rate in the nasal perifoveal region (zone 2) may be associated with subsequent clinically meaningful visual decline.
4.Gallbladder Cancer in a Patient with Anomalous Union of the Pancreaticobiliary Duct: A Case Report
Jeongwoo KIM ; Kyo-Sang YOO ; Kyoung A KO ; Hyeongseok LEE ; Dong Kyu LEE ; Jiwoong JANG ; Sung Hee JUNG
Korean Journal of Pancreas and Biliary Tract 2026;31(1):24-29
Anomalous union of the pancreaticobiliary duct (AUPBD) is a congenital malformation in which the pancreatic and biliary ducts join outside the duodenal wall, forming an elongated common channel. Because sphincter action does not directly affect this junction, reciprocal reflux of pancreatic juice and bile occurs, increasing the risk of biliary tract cancer. AUPBD is frequently associated with choledochal cysts and is a known risk factor for biliary malignancies. We report a case of a 70-year-old woman diagnosed with gallbladder cancer with liver metastases, accompanied by AUPBD without choledochal cysts. She presented with upper abdominal pain, obstructive jaundice, and a large hepatic mass on imaging. Endoscopic retrograde cholangiopancreatography confirmed pancreatobiliary-type AUPBD. Despite biliary drainage, her condition rapidly deteriorated and she died soon after. This case underscores the role of AUPBD in carcinogenesis and the need for early recognition and management.
5.Impact of Thyroid CT on Detecting Macroscopic Nodal Metastasis in Patients With Papillary Thyroid Microcarcinoma
Young Hun JEON ; Ji Ye LEE ; Taehyuk HAM ; Kyu Sung CHOI ; Inpyeong HWANG ; Roh-Eul YOO ; Koung Mi KANG ; Ji-hoon KIM
Korean Journal of Radiology 2026;27(5):484-494
Objective:
To evaluate the impact of adding CT to ultrasound (US) for nodal assessment in patients with papillary thyroid microcarcinoma (PTMC), particularly in those with US-node-negative disease.
Materials and Methods:
This single-center retrospective study included consecutive patients with PTMC (≤1 cm on US) who underwent both US and CT for PTMC staging between August 2016 and January 2020, and subsequently underwent surgery including neck dissection. The number of patients with clinical N1 and pathological N1 disease was assessed. The diagnostic performance of US, CT, and combined US + CT (positive if either was positive) for macroscopic lymph node metastasis (LNM) (i.e., metastatic tumor foci >2 mm) was evaluated. Cases with discordant nodal staging between US and CT were identified.The diagnostic utility of CT was also assessed in a subgroup of patients with node-negative findings on US.
Results:
Among 982 patients (mean age ± standard deviation, 47.3 ± 11.5 years; 774 female), pathological analysis confirmed cervical LNM in 377 patients, including macroscopic, microscopic, and size-unknown LNM in 187, 175, and 15 patients, respectively. The addition of CT to US improved sensitivity for detecting macroscopic LNM compared to US alone (68.4% [128/187] vs. 26.7% [50/187]; P < 0.001), while maintaining high specificity despite a significant decrease (90.9% [709/780] vs. 97.2% [758/780]; P < 0.001). Discordant nodal staging between US and CT regarding macroscopic LNM was observed in 149 cases (15.2% [149/982]), with 131 patients (87.9% [131/149]) being upstaged by CT. In patients with node-negative US findings, CT detected US-undetected macroscopic LNM in 78 patients (8.7% [78/895]) and exhibited a sensitivity of 56.9% (78/137) and specificity of 93.5% (709/758) for macroscopic LNM.
Conclusion
The integration of CT with US improved sensitivity for detecting macroscopic LNM in patients with PTMC, identifying those who would otherwise be inappropriately considered candidates for active surveillance based solely on US findings. This may assist in refining patient management.
6.Eradication of Aspiculuris tetraptera in various immunodeficient mouse models using ivermectin: a case report
Ji-Hun LEE ; Eun-Seon YOO ; Na-Won KIM ; Han-Bi JEONG ; Ah-Reum KANG ; Sun-Min SEO ; Young-Jun PARK ; Byeong-Cheol KANG ; Yang-Kyu CHOI
Laboratory Animal Research 2026;42(1):82-87
Background:
Despite advancements in laboratory animal facility management, pinworm infections remain a persistent issue in immunodeficient mouse colonies. Rapid diagnosis and treatment are crucial to mitigating potential scientific and economic consequences. Effective control requires both the administration of anthelmintic agents and rigorous environmental decontamination. However, the safety and efficacy of these treatments in genetically modified mouse models remains uncertain.Case presentation Aspiculuris tetraptera infestation was identified in multiple immunodeficient mouse models housed in a laboratory facility. Diagnosis was confirmed through fecal flotation for egg detection and necropsy for adult worm examination in the large intestines. Mice received three subcutaneous ivermectin injections at two-week intervals, coupled with environmental decontamination using ivermectin spray for four consecutive weeks. Following treatment, all colonies tested negative for A. tetraptera without any mortality.
Conclusions
A combination of subcutaneous ivermectin injection and environmental spray application effectively eradicated A. tetraptera infestation in immunodeficient mouse colonies. The treatment protocol led to the complete elimination of eggs and adult worms, offering a practical strategy for managing pinworm infections in genetically modified mouse models. Limitations include the small sample size, and the lack of a comprehensive evaluation of physiological and metabolic safety in immunodeficient mice. Further validation will be required to confirm the broader applicability of this approach.
7.Application of Enhanced Recovery After Surgery in high-risk patients undergoing colon cancer surgery:a retrospective cohort study
Reem Mohammed H. ALSHIAKH ; In Kyeong KIM ; Jung Hoon BAE ; Yoon Suk LEE ; In Kyu LEE
Annals of Surgical Treatment and Research 2026;110(4):205-215
Purpose:
Enhanced Recovery After Surgery (ERAS) protocols have demonstrated significant benefits, but their safety and effectiveness in high-risk patients remain unclear. This study evaluated clinical postoperative outcomes in elderly patients and those with comorbidities undergoing colon cancer surgery.
Methods:
This retrospective cohort study included 1,035 patients who underwent elective colon cancer surgery from 2017 to 2022. A standardized 25-element ERAS protocol was implemented across all groups. Patients were categorized into a control group (aged <70 years without comorbidities, n = 534) and high-risk groups including elderly patients (≥70 years, n = 312) and those with cardiac (n = 60), pulmonary (n = 81), renal (n = 24), or hepatic disease (n = 24).
Results:
ERAS compliance rates were significantly lower in all high-risk groups compared to controls (79.39% ± 10.9%), with renal disease patients showing the most pronounced reduction (69.69% ± 17.0%). Post-hoc analysis revealed that only renal disease patients demonstrated significantly higher complication rates (45.8% vs. 18.9%, P < 0.01). Despite lower compliance, multivariate analysis revealed ERAS compliance ≥70% as the strongest independent predictor of both length of stay (odds ratio [OR], 0.139; P < 0.001) and complications (OR, 0.298; P < 0.001), substantially outweighing patient risk factors. After adjusting for treatment factors, patient comorbidity groups showed no independent association with clinical outcomes.
Conclusion
ERAS protocols can be successfully implemented in high-risk patients with appropriate attention to compliance optimization. Treatment factors, particularly ERAS adherence, consistently outweigh patient risk factors in determining outcomes, and well-tailored ERAS implementation should be considered with high-risk patients for perioperative care.
8.WWP2 ubiquitin ligase promotes colorectal cancer progression by targeting p53 for degradation:an experimental study
Seung-Jun LEE ; Han-Gil KIM ; Young-Tae JU ; Young-Sool HAH ; Jeongyun HWANG ; Jihun CHOI ; Jin-Kyu CHO ; Chi-Young JEONG ; Young-Joon LEE ; Ji-Ho PARK ; Ju-Yeon KIM ; Jae-Myung KIM ; Seung-Jin KWAG
Annals of Surgical Treatment and Research 2026;110(5):331-346
Purpose:
Colorectal cancer (CRC) remains a leading cause of cancer-related mortality, necessitating the identification of novel therapeutic targets. The E3 ubiquitin ligase WW domain-containing E3 ubiquitin protein ligase 2 (WWP2) has been implicated in various cancers, yet its specific role and underlying molecular mechanisms in CRC are poorly understood. This study aimed to investigate the functional role of WWP2 in CRC progression and to elucidate its regulatory mechanisms.
Methods:
WWP2 expression was evaluated in CRC patient tissues and cell lines using immunohistochemistry, quantitative real-time polymerase chain reaction, and western blotting. The biological functions of WWP2 were assessed using in vitro assays for cell proliferation, migration, and invasion following adenovirus-mediated overexpression. The molecular mechanism was investigated by analyzing the protein expression levels of p53 and its downstream target, p21, via western blot. An in vivo xenograft mouse model was used to confirm the oncogenic role of WWP2.
Results:
WWP2 expression was significantly upregulated in CRC tissues. Overexpression of WWP2 promoted CRC cell proliferation, migration, and invasion. Mechanistically, increased WWP2 expression led to a marked reduction in the protein levels of the tumor suppressor p53. Consequently, the expression of the p53 downstream target, the cell cycle inhibitor p21, was also suppressed. In the xenograft model, WWP2 overexpression significantly enhanced tumor growth.
Conclusion
Our findings demonstrate that WWP2 functions as an oncogene in CRC. It promotes cancer progression by destabilizing the tumor suppressor p53 and downregulating p21. This study highlights the WWP2-p53-p21 axis as a potential novel therapeutic target for CRC.
9.Primary Intradural Extramedullary Ewing Sarcoma of the Thoracic Spine With Leptomeningeal and Brain Metastases:A Case Report and Literature Review
Achmad Harun MUCHSIN ; Woochan PARK ; Yu Jung KIM ; Koung Jin SUH ; Jeong Min SEO ; Kyu Sang LEE ; Keun-Yong EOM ; Seung-Jae HYUN
Brain Tumor Research and Treatment 2026;14(2):102-108
A 43-year-old woman presented with bilateral lower extremity weakness due to an intradural extramedullary spinal cord tumor. Surgery revealed Ewing sarcoma, a rare presentation known as primary intradural extramedullary Ewing sarcoma (PIEES). Despite initial treatment with radiation and chemotherapy, tumor recurrence occurred after 17 months. Further interventions included additional surgery, radiation, and chemotherapy. The disease progressed to leptomeningeal metastases along the spinal cord, prompting various treatments including targeted spinal radiation and systemic therapies. Brain metastases subsequently developed, necessitating whole-brain radiation and intrathecal chemotherapy. This case highlights the aggressive nature of PIEES, its potential for widespread leptomeningeal metastasis, and the challenges in its management, underscoring the need for multidisciplinary approaches in treating this rare and aggressive malignancy.
10.Prediction of Cancer Incidence and Mortality in Korea, 2026
Kyu-Won JUNG ; Mee Joo KANG ; Eun Hye PARK ; E Hwa YUN ; Hye-Jin KIM ; Jeong-Eun KIM ; Kui Sun CHOI ; Han-Kwang YANG
Cancer Research and Treatment 2026;58(2):368-375
Purpose:
This study aimed to project cancer incidence and mortality for 2026 to estimate Korea’s current cancer burden.
Materials and Methods:
Cancer incidence data from 1999 to 2023 were obtained from the Korea National Cancer Incidence Database, while cancer mortality data from 1993 to 2024 were acquired from the Ministry of Data and Statistics. Cancer incidence and mortality were projected by fitting a linear regression model to observed age-specific cancer rates against their respective years and then by the projected age-specific rates by the anticipated age-specific population for 2026. A joinpoint regression model was applied to identify significant changes in trends, using only the most recent trend data for predictions.
Results:
A total of 308,876 new cancer cases and 86,317 cancer deaths are expected in Korea in 2026. The most commonly diagnosed cancer is projected to be thyroid cancer, followed by the colorectal, lung, breast, prostate and stomach cancers. These six cancers are expected to account for 63.5% of all newly diagnosed cancers. Lung cancer is expected to be the leading cause of cancer-related deaths, followed by liver, colorectal, pancreatic, gallbladder, and stomach cancers, together comprising 65.9% of all cancer deaths.
Conclusion
Korea’s cancer burden continues to shift toward malignancies prevalent in older populations. The sustained increase in prostate cancer among men and the rising mortality impact of pancreatic cancer reflect structural changes in the national cancer profile amid rapid population aging.

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