Background: s/Aims: Reported incidence of extrahepatic bile duct cancer is higher in Asians than in Western populations. Korea, in particular, is one of the countries with the highest incidence rates of extrahepatic bile duct cancer in the world. Although research and innovative therapeutic modalities for extrahepatic bile duct cancer are emerging, clinical guidelines are currently unavailable in Korea. The Korean Society of Hepato-Biliary-Pancreatic Surgery in collaboration with related societies (Korean Pancreatic and Biliary Surgery Society, Korean Society of Abdominal Radiology, Korean Society of Medical Oncology, Korean Society of Radiation Oncology, Korean Society of Pathologists, and Korean Society of Nuclear Medicine) decided to establish clinical guideline for extrahepatic bile duct cancer in June 2021. Methods: Contents of the guidelines were developed through subgroup meetings for each key question and a preliminary draft was finalized through a Clinical Guidelines Committee workshop. Results: In November 2021, the finalized draft was presented for public scrutiny during a formal hearing. Conclusions The extrahepatic guideline committee believed that this guideline could be helpful in the treatment of patients.

Purpose: This study aimed to assess the feasibility and safety of administering intraoperative radiotherapy (IORT) as a boost during breast-conserving surgery (BCS) following neoadjuvant chemotherapy for patients at high risk of breast cancer recurrence. Materials and Methods: Patients who underwent neoadjuvant chemotherapy received a single 20-Gy dose of IORT during BCS, followed by external beam radiotherapy 4–6 weeks after surgery. Results: The median follow-up duration was 31.0 months (range, 18.0–59.0 months). Initial tumor sizes had a median of 2.6 cm (range: 0.8–5.3 cm), reducing to 0.3 cm (range: 0–4.0 cm) after neoadjuvant chemotherapy. The most common neoadjuvant chemotherapy regimen was doxorubicin and cyclophosphamide, followed by paclitaxel (n=42, 73.7%). Among 57 patients who received neoadjuvant chemotherapy before BCS and IORT, 2 patients (3.5%) required secondary surgery to achieve negative resection margins due to initially positive margins. Regional lymph node irradiation was performed in 37 (64.9%) patients. There was no grade 3 or higher adverse events, with 4 patients (7.0%) experiencing grade 2 acute radiation dermatitis and 3 (5.3%) having less than grade 2 breast edema. Binary correlation analysis did not reveal statistically significant associations between applicator size or radiation therapy modality and the risk of treatment-related toxicity. Furthermore, chi-square analysis showed that the grade of treatment-related toxicity was not associated with the fractionated regimen (p=0.375). Conclusion Most patients successfully received IORT as a tumor bed boost after neoadjuvant chemotherapy. Thus, IORT may be a safe and feasible option for patients with advanced-stage breast cancer receiving neoadjuvant chemotherapy.

Objectives: . This study aimed to present our experiences with various approaches for endoscopic thyroidectomy (ET) and to offer lessons for choosing an approach. Methods: . The medical records of 701 patients who underwent ET via the transaxillary (TA), bilateral axillo-breast (BABA), unilateral axillo-breast with carbon dioxide insufflation (UABA), retroauricular (RA), or transoral vestibular (TO) approach between May 2008 and March 2020 were retrospectively reviewed. Postoperative pain and cosmetic outcomes were evaluated using visual analog scales. Results: . The mean operative time of UABA was the shortest among the five approaches (TA, 194.65±51.13 minutes; BABA, 189.11±61.53 minutes; UABA, 118.62±30.23 minutes; RA, 168.22±45.63 minutes; TO, 196.10±40.19 minutes; P=0.02). BABA was the most painful approach, while TO was the least painful on postoperative day 1 (TA, 3.09±0.96; BABA, 3.59±0.92; UABA, 2.39±0.54; RA, 3.49±0.93; TO, 2.01±0.37; P=0.04) and day 3 (TA, 2.10±0.77; BABA, 2.59±0.88; UABA, 1.84±0.37; RA, 3.01±0.67; TO, 1.49±0.45; P=0.04). The TO group had the best cosmetic outcomes at 3 months (TA, 3.91±1.21; BABA, 4.52±1.13; UABA, 4.49±0.74; RA, 4.28±0.74; TO, 4.81±0.48; P=0.04). Conclusion . We present a single-surgeon experience of five distinctive ET approaches and the lessons from each approach, together with a literature review. This data may aid endoscopic thyroid surgeons in choosing from various ET approaches.

Background and Objectives: The purpose of this study was to examine the benefits of ultrasonography performed by a surgeon rather than a radiologist.Subjects and Method This retrospective study enrolled 122 cases of ultrasonography performed by a head and neck surgeon and 116 cases of the same examination performed by a radiologist before surgery. The time intervals between the first visit and surgery were compared in both groups. Results: The average waiting time for surgery after the first hospital visit was significantly reduced when a surgeon performed the ultrasound examination. Furthermore, there was no significant difference in sampling inadequacy rate on thyroid fine needle aspiration (FNA) between FNA performed by a head and neck surgeon and a radiologist. Conclusion Surgeons can utilize ultrasound as a diagnostic and therapeutic tool in an office-based setting. For patients, diagnosis and treatment provided by a single doctor will lead to more efficient outcomes.

Objectives: . Head and neck squamous cell carcinomas (HNSCs) are frequently diagnosed at the locoregional advanced stage (stage IVa), but controversy remains regarding whether stage IVa HSNCs should be treated with upfront surgery or definitive chemoradiation therapy (CRT). The purpose of this study was to compare overall survival (OS) and disease-free survival (DFS) in patients with stage IVa HNSC treated primarily by surgery with curative intent with/without (neo)adjuvant treatment (surgery group) versus those treated primarily with CRT (CRT group). Methods: . We reviewed data of 1,033 patients with stage IVa HNSC treated with curative intent at 17 cancer centers between 2010 and 2016. Results: . Among 1,033 patients, 765 (74.1%) received upfront surgery and 268 (25.9%) received CRT. The 5-year OS and DFS rates were 64.4% and 62.0% in the surgery group and 49.5% and 45.4% in the CRT group, respectively. In multivariate analyses, OS and DFS were better in the surgery group than in the CRT group (odds ratio [OR] for death, 0.762; 95% confidence interval [CI], 0.592–0.981; OR for recurrence, 0.628; 95% CI, 0.492–0.802). In subgroup analyses, the OS and DFS of patients with oropharyngeal cancer were better in the surgery group (OR for death, 0.548; 95% CI, 0.341–0.879; OR for recurrence, 0.598; 95% CI, 0.377–0.948). In the surgery group, patients with laryngeal cancer showed better OS (OR for death, 0.432; 95% CI, 0.211–0.882), while those with hypopharyngeal cancer DFS was improved (OR for recurrence, 0.506; 95% CI, 0.328–0.780). Conclusion . A survival benefit from surgery may be achieved even in patients with stage IVa HNSC, particularly those with oropharyngeal and laryngeal cancer. Surgery led to a reduction in the recurrence rate in patients with hypopharyngeal cancer.

Purpose: Li-Fraumeni syndrome (LFS) is a rare autosomal cancer syndrome caused by a germline mutation in the TP53 gene. Breast cancer in LFS patients is of various subtypes;however, limited data are available on the clinicopathological features of these subtypes and their appropriate treatments. This study aimed to review the clinical features and treatments for breast cancer in South Korean patients with germline TP53 mutations. Methods: Data on the clinicopathological features and treatment of all breast cancer patients with LFS were collected retrospectively from the available database of 4 tertiary hospitals in the Republic of Korea. Results: Twenty-one breast cancer cases in 12 unrelated women with confirmed germline TP53 mutations were included in the study. The median age at diagnosis was 33.5 years. The histopathological diagnosis included invasive ductal carcinoma (n = 16), ductal carcinoma in situ (n = 3), and malignant phyllodes tumor (n = 2). While 42% and 31% of the cases were positive for estrogen and progesterone receptors, respectively, 52.6% were human epidermal growth factor receptor 2 (HER2) positive, and 21% were triple-negative. The treatments included mastectomy (52%) and breast-conserving surgery (38%). Five patients underwent radiotherapy (RT). The median follow-up period was 87.5 (8–222) months. There were 3 ipsilateral and 4 contralateral breast recurrences during the follow-up, and 8 patients developed new primary cancers. In the post-RT subgroup, there were 2 ipsilateral and 2 contralateral breast recurrences in 1 patient, and 4 patients had a new primary cancer. Conclusion As reported in other countries, breast cancer in LFS patients in South Korea had an early onset and were predominantly but not exclusively positive for HER2.A multidisciplinary approach with adherence to the treatment guidelines, considering mastectomy, and avoiding RT is encouraged to prevent RT-associated sequelae in LFS patients.

Background: and Purpose We aimed to develop a model predicting early recanalization after intravenous tissue plasminogen activator (t-PA) treatment in large-vessel occlusion. Methods: Using data from two different multicenter prospective cohorts, we determined the factors associated with early recanalization immediately after t-PA in stroke patients with large-vessel occlusion, and developed and validated a prediction model for early recanalization. Clot volume was semiautomatically measured on thin-section computed tomography using software, and the degree of collaterals was determined using the Tan score. Follow-up angiographic studies were performed immediately after t-PA treatment to assess early recanalization. Results: Early recanalization, assessed 61.0±44.7 minutes after t-PA bolus, was achieved in 15.5% (15/97) in the derivation cohort and in 10.5% (8/76) in the validation cohort. Clot volume (odds ratio [OR], 0.979; 95% confidence interval [CI], 0.961 to 0.997; P=0.020) and good collaterals (OR, 6.129; 95% CI, 1.592 to 23.594; P=0.008) were significant factors associated with early recanalization. The area under the curve (AUC) of the model including clot volume was 0.819 (95% CI, 0.720 to 0.917) and 0.842 (95% CI, 0.746 to 0.938) in the derivation and validation cohorts, respectively. The AUC improved when good collaterals were added (derivation cohort: AUC, 0.876; 95% CI, 0.802 to 0.950; P=0.164; validation cohort: AUC, 0.949; 95% CI, 0.886 to 1.000; P=0.036). The integrated discrimination improvement also showed significantly improved prediction (0.097; 95% CI, 0.009 to 0.185; P=0.032). Conclusions The model using clot volume and collaterals predicted early recanalization after intravenous t-PA and had a high performance. This model may aid in determining the recanalization treatment strategy in stroke patients with large-vessel occlusion.

Background and Objectives: Smoking is well-established as a risk factor for coronary artery disease. However, recent studies demonstrated favorable results, including reduced mortality, among smokers, which are referred to as the “smoker's paradox”. This study examined the impact of smoking on clinical outcomes in patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI). Methods: Patients with AMI undergoing PCI between 2004 and 2014 were enrolled and classified according to smoking status. The primary endpoint was a composite of major adverse cardiovascular events (MACE) including cardiac death, myocardial infarction, stroke, and revascularization. Results: Among the 10,683 patients, 4,352 (40.7%) were current smokers. Smokers were 10.7 years younger and less likely to have comorbidities such as hypertension, diabetes mellitus, chronic kidney disease, stroke, and prior PCI. Smokers had less MACE (hazard ratio [HR], 0.644; 95% confidence interval [CI], 0.594–0.698; p<0.001) and cardiac death (HR, 0.494; 95% CI, 0.443–0.551; p<0.001) compared to nonsmokers during the 5 years in an unadjusted model. However, after propensity-score matching, smokers showed higher risk of MACE (HR, 1.125; 95% CI, 1.009–1.254; p=0.034) and cardiac death (HR, 1.190; 95% CI, 1.026–1.381; p=0.022). Smoking was a strong independent predictor of lung cancer (propensityscore matched HR, 2.749; 95% CI, 1.416–5.338; p=0.003). Conclusions In contrast to the unadjusted model, smoking is associated with worse cardiovascular outcome and higher incidence of lung cancer after adjustment of various confounding factors. This result can be explained by the characteristics of smokers, which were young and had fewer comorbidities.

Background and Objectives: Smoking is well-established as a risk factor for coronary artery disease. However, recent studies demonstrated favorable results, including reduced mortality, among smokers, which are referred to as the “smoker's paradox”. This study examined the impact of smoking on clinical outcomes in patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI). Methods: Patients with AMI undergoing PCI between 2004 and 2014 were enrolled and classified according to smoking status. The primary endpoint was a composite of major adverse cardiovascular events (MACE) including cardiac death, myocardial infarction, stroke, and revascularization. Results: Among the 10,683 patients, 4,352 (40.7%) were current smokers. Smokers were 10.7 years younger and less likely to have comorbidities such as hypertension, diabetes mellitus, chronic kidney disease, stroke, and prior PCI. Smokers had less MACE (hazard ratio [HR], 0.644; 95% confidence interval [CI], 0.594–0.698; p<0.001) and cardiac death (HR, 0.494; 95% CI, 0.443–0.551; p<0.001) compared to nonsmokers during the 5 years in an unadjusted model. However, after propensity-score matching, smokers showed higher risk of MACE (HR, 1.125; 95% CI, 1.009–1.254; p=0.034) and cardiac death (HR, 1.190; 95% CI, 1.026–1.381; p=0.022). Smoking was a strong independent predictor of lung cancer (propensityscore matched HR, 2.749; 95% CI, 1.416–5.338; p=0.003). Conclusions In contrast to the unadjusted model, smoking is associated with worse cardiovascular outcome and higher incidence of lung cancer after adjustment of various confounding factors. This result can be explained by the characteristics of smokers, which were young and had fewer comorbidities.

Background and Objectives: Follicular thyroid carcinoma (FTC) is the second common thyroid cancer which comprises about 10% of differentiated thyroid carcinoma. Hurthle cell carcinoma (HCC) is a relatively rare disease that has been classified as a subtype of FTC. However, there have been insufficient reports about these two similar thyroid cancers in South Korea due to low incidences. This study aims to present clinical features and evaluate prognostic factors of FTC and HCC.Subjects and Method We reviewed data of 189 FTC and 12 HCC patients who underwent surgery in our center from January 2000 to December 2020. Variables such as clinical characteristics, surgical method, pathologic result, post-operative treatment, survival rate and prognostic factors were included in our study. Results: As for age, 67.2% of patients in FTC group and 33.3% of patients in HCC group were older than 55 years-old (p=0.017). The average tumor sizes of FTC and HCC were 2.98 and 3.1 cm, respectively. The 10-year overall survival rates of FTC and HCC were 96.5% and 100%, respectively. The 10-year disease free survival rates of FTC and HCC were 89.1% and 91.7%, respectively. Subclassification (widely invasive: p=0.036) and initial distant metastasis (p<0.001) were significant prognostic factors in FTC. Conclusion This study will be helpful for diagnosis and treatment of FTC and HCC, which are relatively rare.