Objectives: Estimating the number of deaths caused by smoking is crucial for developing and evaluating tobacco control and smoking cessation policies. This study aimed to determine smoking-attributable mortality (SAM) in Korea in 2020. Methods: Four large-scale cohorts from Korea were analyzed. A Cox proportional-hazards model was used to determine the hazard ratios (HRs) of smoking-related death. By conducting a meta-analysis of these HRs, the pooled HRs of smoking-related death for 41 diseases were estimated. Population-attributable fractions (PAFs) were calculated based on the smoking prevalence for 1995 in conjunction with the pooled HRs. Subsequently, SAM was derived using the PAF and the number of deaths recorded for each disease in 2020. Results: The pooled HR for all-cause mortality attributable to smoking was 1.73 for current men smokers (95% confidence interval [CI], 1.53 to 1.95) and 1.63 for current women smokers (95% CI, 1.37 to 1.94). Smoking accounted for 33.2% of all-cause deaths in men and 4.6% in women. Additionally, it was a factor in 71.8% of men lung cancer deaths and 11.9% of women lung cancer deaths. In 2020, smoking was responsible for 53 930 men deaths and 6283 women deaths, totaling 60 213 deaths. Conclusions Cigarette smoking was responsible for a significant number of deaths in Korea in 2020. Monitoring the impact and societal burden of smoking is essential for effective tobacco control and harm prevention policies.

Background: Radiation exposure is a well-known risk factor for papillary thyroid cancer (PTC). South Korea has 24 nuclear reactors in operation; however, no molecular biological analysis has been performed on patients with PTC living near nuclear power plants. Methods: We retrospectively included patients with PTC (n=512) divided into three groups according to their place of residence at the time of operation: inland areas (n=300), coastal areas far from nuclear power plants (n=134), and nuclear power plant areas (n=78). After propensity score matching (1:1:1) by age, sex, and surgical procedure, the frequency of representative driver mutations and gene expression profiles were compared (n=50 per group). Epithelial-mesenchymal transition (EMT), BRAF, thyroid differentiation, and radiation scores were calculated and compared. Results: No significant difference was observed in clinicopathological characteristics, including radiation exposure history and the frequency of incidentally discovered thyroid cancer, among the three groups. BRAFV600E mutation was most frequently detected in the groups, with no difference among the three groups. Furthermore, gene expression profiles showed no statistically significant difference. EMT and BRAF scores were higher in our cohort than in cohorts from Chernobyl tissue bank and The Cancer Genome Atlas Thyroid Cancer; however, there was no difference according to the place of residence. Radiation scores were highest in the Chernobyl tissue bank but exhibited no difference according to the place of residence. Conclusion Differences in clinicopathological characteristics, frequency of representative driver mutations, and gene expression profiles were not observed according to patients’ region of residence in South Korea.

Background and Objectives: Although thyroid hormones affect human cancer progression, the regulatory mechanism of thyroid hormone receptors in carcinogenesis has not been elucidated. This study aimed to evaluate the expression pattern of the thyroid hormone receptor (TR) and its corepressors, and to investigate the clinical and biological functions of TR. Materials and Methods: Transcriptomic and clinical data for thyroid cancer were downloaded from The Cancer Genome Atlas. Paraffin-embedded tissue sections from patients who underwent thyroidectomy were used for immunohistochemistry. BCPAP cells were treated with T3 to investigate the thyroid hormone target genes. Thyroid hormone receptor alpha (THRA) and Thyroid hormone receptor beta (THRB) were knocked down by transient siRNA transfection. Results: THRA and THRB expression was lower in thyroid cancer tissues than in normal tissues. However, strong focal staining of TRβ was observed in the invasive front. High THRB expression was associated with high Silencing Mediator for Retinoid or Thyroid hormone receptor (SMRT) expression, older age, a high MACIS (distant Metastasis, patient Age, Completeness of resection, local Invasion, and tumor Size) score, more aggressive histological subtypes, more frequent extra-thyroidal extension, and advanced TNM stage. THRB expression was positively correlated with Hypoxia Inducible Factor 1 Subunit Alpha (HIF1A), L1 Cell Adhesion Molecule (L1CAM), and Lysyl Oxidase (LOX) expression. Thyroid hormone-induced HIF1A, L1CAM, and LOX upregulation was abolished by siTHRB but not siTHRA in BCPAP cells. High SMRT and high THRB groups (SMRT/THRB) presented more aggressive clinical features and showed an upregulation of HIF1A, L1CAM, and LOX, as well as of epithelial-mesenchymal transition (EMT)-related genes, causing changes in the tumor microenvironment. Conclusion Cooperative subtype switching from NCOR1/THRA to SMRT/THRB was thus related to aggressive clinical and molecular features, possibly related to EMT and EMT-related tumor microenvironment.

PURPOSE: Lung Cancer Subcommittee of Korean Radiation Oncology Group (KROG) has recently launched a prospective clinical trial (KROG 17-06) of hippocampus-sparing whole brain radiotherapy (HS-WBRT) with simultaneous integrated boost (SIB) in treating multiple brain metastases from non-small cell lung cancer. In order to improve trial quality, dummy run studies among the participating institutions were designed. This work reported the results of two-step dummy run procedures of the KROG 17-06 study. MATERIALS AND METHODS: Two steps tested hippocampus contouring variability and radiation therapy planning compliance. In the first step, the variation of the hippocampus delineation was investigated for two representative cases using the Dice similarity coefficients. In the second step, the participating institutions were requested to generate a HS-WBRT with SIB treatment plan for another representative case. The compliance of the treatment plans to the planning protocol was evaluated. RESULTS: In the first step, the median Dice similarity coefficients of the hippocampus contours for two other dummy run cases changed from 0.669 (range, 0.073 to 0.712) to 0.690 (range, 0.522 to 0.750) and from 0.291 (range, 0.219 to 0.522) to 0.412 (range, 0.264 to 0.598) after providing the hippocampus contouring feedback. In the second step, with providing additional plan priority and extended dose constraints to the target volumes and normal structures, we observed the improved compliance of the treatment plans to the planning protocol. CONCLUSION: The dummy run studies demonstrated the notable inter-institutional variability in delineating the hippocampus and treatment plan generation, which could be decreased through feedback from the trial center.
Brain ; Carcinoma, Non-Small-Cell Lung ; Compliance ; Hippocampus ; Lung Neoplasms ; Neoplasm Metastasis ; Prospective Studies ; Radiation Oncology ; Radiotherapy

BACKGROUND/AIMS: To evaluate the technical feasibility of stereotactic body radiotherapy (SBRT) for hepatocellular carcinoma (HCC) with the major portal vein tumor thrombosis (PVTT). METHODS: Ten institutions affiliated with the Korean Stereotactic Radiosurgery Group were provided the contours of four cases: the first case was the first branch PVTT with sufficient normal liver volume (NLV), the second was the first branch PVTT with insufficient NLV, the third was the main trunk PVTT at confluence level, and the fourth was the main trunk PVTT with entire length. The institutions were asked to make SBRT plans according to their current treatment protocols and to complete facility questionnaires. RESULTS: Based on institutional protocols, SBRT was feasible in nine institutions for the first case (32–60 Gy in 3–5 fractions), in eight institutions for the second case (32–50 Gy in 3–5 fractions), in seven institutions for the third case (35–60 Gy in 3–5 fractions), and in four institutions for the fourth case (35–42 Gy in 4–5 fractions). The other institutions recommended hypo- or conventional fractionation due to insufficient NLV or gastrointestinal organ proximity. With analysis of the SBRT dose to the central hepatobiliary tract, the major PVTT could theoretically be associated with a high risk of hepatobiliary toxicity. CONCLUSIONS: Although SBRT is a technically feasible option for HCC with the major PVTT, there was a variability among the participating institutions. Therefore, further studies will be necessary to standardize the practice of SBRT for the major PVTT.
Carcinoma, Hepatocellular ; Clinical Protocols ; Liver ; Portal Vein ; Radiosurgery ; Thrombosis

PURPOSE: This study aimed to evaluate the effects of radiotherapy (RT) on progression-free survival (PFS) for patients with recurrent colorectal cancer. METHODS: We reviewed the records of 22 patients with recurrent colorectal cancer treated with RT between 2008 and 2014. The median radiation dose for recurrent disease was 57.6 Gy (range, 45-75.6 Gy). Patients were divided into 2 groups according to the type of RT: patients underwent RT without previous history of irradiation (n = 14) and those treated with secondary RT (reirradiation: n = 8) at the time of recurrence. RESULTS: The median follow-up period was 24.9 months (range, 4.5-66.6 months). Progression was observed in 14 patients (including 8 with loco-regional failure and 9 with distant metastases). Distant metastases were related to the RT dose (<70 Gy, P = 0.031). The 2-year loco-regional control (LRC), PFS, and overall survival (OS) rates were 74.6%, 45.1%, and 82.0%, respectively. The LRC rate was not different between the patients treated with RT for the first time and those treated with reirradiation (P = 0.101, 2-year LRC 79.5% vs. 41.7%). However, reirradiation was related to poor PFS (P = 0.022) and OS (P = 0.002). An escalated RT dose (≥70 Gy) was associated with a higher PFS (P = 0.014, 2-year PFS 63.5% vs. 20.8%). CONCLUSION: Salvage RT for locally recurrent colorectal cancer can be offered when surgery is impossible. Dose-escalated RT shows a possible benefit in reducing the risk of progression.
Colorectal Neoplasms* ; Disease-Free Survival ; Follow-Up Studies ; Humans ; Neoplasm Metastasis ; Radiotherapy* ; Rectal Neoplasms ; Recurrence

PURPOSE: The purpose of this study is to investigate the current status of stereotactic body radiotherapy (SBRT) in Korea. A nationwide survey was conducted by the Korean Stereotactic Radiosurgery Group of the Korean Society for Radiation Oncology (KROG 13-13). MATERIALS AND METHODS: SBRT was defined as radiotherapy with delivery of a high dose of radiation to an extracranial lesion in < or = 4 fractions. A 16-questionnaire survey was sent by e-mail to the chief of radiation oncology at 85 institutions in June 2013. RESULTS: All institutions (100%) responded to this survey. Of these, 38 institutions (45%) have used SBRT and 47 institutions (55%) have not used SBRT. Regarding the treatment site, the lung (92%) and liver (76%) were the two most common sites. The most common schedules were 60 Gy/4 fractions for non-small cell lung cancer, 48 Gy/4 fractions for lung metastases, 60 Gy/3 fractions for hepatocellular carcinoma, and 45 Gy/3 fractions or 40 Gy/4 fractions for liver metastases. Four-dimensional computed tomography (CT) was the most common method for planning CT (74%). During planning CT, the most common method of immobilization was the use of an alpha cradle/vacuum-lock (42%). CONCLUSION: Based on this survey, conduct of further prospective studies will be needed in order to determine the appropriate prescribed doses and to standardize the practice of SBRT.
Appointments and Schedules ; Carcinoma, Hepatocellular ; Carcinoma, Non-Small-Cell Lung ; Electronic Mail ; Four-Dimensional Computed Tomography ; Immobilization ; Korea ; Liver ; Lung ; Neoplasm Metastasis ; Radiation Oncology ; Radiosurgery* ; Radiotherapy

Although significant advances in the treatment of intrahepatic lesions, it is reported that the prognosis for patients with hepatocellular carcinoma (HCC) who have extrahepatic metastasis remains poor. We report a patient with lung, liver, brain, bone and subcutaneous metastasis from HCC who has survived more than 7 years maintaining relatively good performance status as a result of repeated therapies. A 55-year-old male patient with HCC underwent right lobectomy of the liver and cholecystectomy in September 2006. He received wedge resection for lung metastasis twice (July 2009, January 2011) and Gamma Knife stereotactic radiosurgery for brain metastasis (April 2011). Over the last 3 years, he has developed metastasis in subcutaneous tissues, muscle, and bone with pain. He has undergone 7 courses of radiotherapies for subcutaneous tissues, muscle, and bone metastasis and been prescribed sorafenib and he is still capable of all self-care.
Brain ; Carcinoma, Hepatocellular* ; Cholecystectomy ; Humans ; Liver ; Lung ; Male ; Middle Aged ; Muscles ; Neoplasm Metastasis* ; Prognosis ; Radiosurgery ; Radiotherapy* ; Self Care ; Subcutaneous Tissue

Due to improved life spans, cancer incidence has increased with more aged patients presenting with cancer. Elderly cancer patients could have compromised organ function and/or comorbidities. Due to poor social support or lack of early diagnosis, treatment outcomes for elderly cancer patients are poor in general. However, with aggressive support during cancer management as well as careful selection, most elderly cancer patients can tolerate standard radiation therapy with good results based on published articles. Here, we reviewed existing articles regarding compliance and treatment results in elderly cancer patients based on tumor site.
Aged ; Comorbidity ; Compliance ; Early Diagnosis ; Humans ; Incidence

BACKGROUND: The purpose of this study was to explore the factors related to internet addiction in college students in Korea. METHODS: This study was a cross-sectional survey of college students in Seoul, and data was collected through self-report questionnaires. Data was analyzed by one-way analysis of variance, Fisher's exact test, Kruskal-Wallis rank test, and ordinary logistic regression analysis. RESULTS: In the ordinary logistic regression analysis, the factors related to a higher risk of internet addiction were lower frequency of exercise (P=0.017), lower level of self-control (P<0.001), higher level of stress (P<0.001), living with parents (P=0.011), using the internet for extended periods of time (P<0.001), and using the internet in their own rooms (P<0.001). CONCLUSIONS: Our results suggest that exercise, self-control, stress, living with parents, and duration and place of internet use are associated with internet addiction in college students. This information can be used to design methods for preventing internet addiction. More specific studies on internet addiction in college students are needed.
Behavior, Addictive ; Cross-Sectional Studies ; Humans ; Hypogonadism ; Internet ; Logistic Models ; Mitochondrial Diseases ; Ophthalmoplegia ; Parents ; Surveys and Questionnaires