Background: Epidermal growth factor receptor (EGFR) gene mutation testing is crucial for the administration of tyrosine kinase inhibitors to treat non–small cell lung cancer. In addition to traditional tissue-based tests, liquid biopsies using plasma are increasingly utilized, particularly for detecting T790M mutations. This study compared tissue- and plasma-based EGFR testing methods. Methods: A total of 248 patients were tested for EGFR mutations using tissue and plasma samples from 2018 to 2023 at Pusan National University Yangsan Hospital. Tissue tests were performed using PANAmutyper, and plasma tests were performed using the Cobas EGFR Mutation Test v2. Results: All 248 patients underwent tissue-based EGFR testing, and 245 (98.8%) showed positive results. Of the 408 plasma tests, 237 (58.1%) were positive. For the T790M mutation, tissue biopsies were performed 87 times in 69 patients, and 30 positive cases (38.6%) were detected. Plasma testing for the T790M mutation was conducted 333 times in 207 patients, yielding 62 positive results (18.6%). Of these, 57 (27.5%) were confirmed to have the mutation via plasma testing. Combined tissue and plasma tests for the T790M mutation were positive in nine patients (13.4%), while 17 (25.4%) were positive in tissue only and 12 (17.9%) in plasma only. This mutation was not detected in 28 patients (43.3%). Conclusions Although the tissue- and plasma-based tests showed a sensitivity of 37.3% and 32.8%, respectively, combined testing increased the detection rate to 56.7%. Thus, neither test demonstrated superiority, rather, they were complementary.

Background: Epidermal growth factor receptor (EGFR) gene mutation testing is crucial for the administration of tyrosine kinase inhibitors to treat non–small cell lung cancer. In addition to traditional tissue-based tests, liquid biopsies using plasma are increasingly utilized, particularly for detecting T790M mutations. This study compared tissue- and plasma-based EGFR testing methods. Methods: A total of 248 patients were tested for EGFR mutations using tissue and plasma samples from 2018 to 2023 at Pusan National University Yangsan Hospital. Tissue tests were performed using PANAmutyper, and plasma tests were performed using the Cobas EGFR Mutation Test v2. Results: All 248 patients underwent tissue-based EGFR testing, and 245 (98.8%) showed positive results. Of the 408 plasma tests, 237 (58.1%) were positive. For the T790M mutation, tissue biopsies were performed 87 times in 69 patients, and 30 positive cases (38.6%) were detected. Plasma testing for the T790M mutation was conducted 333 times in 207 patients, yielding 62 positive results (18.6%). Of these, 57 (27.5%) were confirmed to have the mutation via plasma testing. Combined tissue and plasma tests for the T790M mutation were positive in nine patients (13.4%), while 17 (25.4%) were positive in tissue only and 12 (17.9%) in plasma only. This mutation was not detected in 28 patients (43.3%). Conclusions Although the tissue- and plasma-based tests showed a sensitivity of 37.3% and 32.8%, respectively, combined testing increased the detection rate to 56.7%. Thus, neither test demonstrated superiority, rather, they were complementary.

Background: Epidermal growth factor receptor (EGFR) gene mutation testing is crucial for the administration of tyrosine kinase inhibitors to treat non–small cell lung cancer. In addition to traditional tissue-based tests, liquid biopsies using plasma are increasingly utilized, particularly for detecting T790M mutations. This study compared tissue- and plasma-based EGFR testing methods. Methods: A total of 248 patients were tested for EGFR mutations using tissue and plasma samples from 2018 to 2023 at Pusan National University Yangsan Hospital. Tissue tests were performed using PANAmutyper, and plasma tests were performed using the Cobas EGFR Mutation Test v2. Results: All 248 patients underwent tissue-based EGFR testing, and 245 (98.8%) showed positive results. Of the 408 plasma tests, 237 (58.1%) were positive. For the T790M mutation, tissue biopsies were performed 87 times in 69 patients, and 30 positive cases (38.6%) were detected. Plasma testing for the T790M mutation was conducted 333 times in 207 patients, yielding 62 positive results (18.6%). Of these, 57 (27.5%) were confirmed to have the mutation via plasma testing. Combined tissue and plasma tests for the T790M mutation were positive in nine patients (13.4%), while 17 (25.4%) were positive in tissue only and 12 (17.9%) in plasma only. This mutation was not detected in 28 patients (43.3%). Conclusions Although the tissue- and plasma-based tests showed a sensitivity of 37.3% and 32.8%, respectively, combined testing increased the detection rate to 56.7%. Thus, neither test demonstrated superiority, rather, they were complementary.

Background/Aims: The proposed eosinophilic esophagitis (EoE) endoscopic reference score serves to diagnose and evaluate treatment responses in EoE.Nevertheless, the validated reference score thresholds for diagnosis and treatment response in Asian patients are yet to be established.This study aims to establish these thresholds for the first time among Asian patients with EoE. Methods: Patients presenting with ≥ 15 eosinophils/high power field and esophageal dysfunction symptoms between August 2007 andNovember 2021 were included. Age- and sex-matched non-EoE controls were also enrolled. Baseline characteristics, endoscopic reference score features, and scores were compared between patients and controls. Among patients, endoscopic reference score features and scores, along with peak eosinophil counts, were evaluated both before and after treatment. The optimal threshold was determined based on sensitivity, specificity, and the Youden index. Results: Overall, 102 patients were enrolled (74.5% men; mean age, 46.9 years). The mean endoscopic reference score was 2.65 and 0.52 for patients and controls, respectively (P < 0.001). An endoscopic reference score ≥ 2 was identified as the optimal diagnostic threshold for EoE (sensitivity, 0.79; specificity, 0.86; Youden index, 0.66). Post-treatment data regarding endoscopic findings and histology wereavailable for 30 patients. Regarding histologic response, an endoscopic reference score of ≤ 3 demonstrated the optimal threshold(sensitivity, 0.95; specificity, 0.88; Youden index, 0.83). Conclusions The optimal diagnostic and treatment response thresholds were determined to be endoscopic reference scores of ≥ 2 and ≤ 3,respectively. Further studies involving a larger patient cohort are necessary to validate these findings.

This study was designed to compare diagnostic categories of thyroid fine needle aspiration cytology (FNAC) and incidence of thyroid tumors in the multi-institutional Asian series with a special focus on diagnostic category IV (suspicious for a follicular neoplasm) and follicular thyroid carcinomas (FTCs). Methods: Distribution of FNAC categories, incidence of thyroid tumors in resection specimens and cytologic diagnoses of surgically confirmed follicular adenomas (FAs) and FTCs were collected from 10 institutes from five Asian countries and were compared among countries and between FAs and FTCs. Results: The frequency of category IV diagnoses (3.0%) in preoperative FNAC were significantly lower compared to those in Western countries (10.1%). When comparing diagnostic categories among Asian countries, category IV was more frequent in Japan (4.6%) and India (7.9%) than in Taiwan (1.4%), Korea (1.4%), and China (3.6%). Similarly, incidence of FAs and FTCs in surgical resection specimens was significantly higher in Japan (10.9%) and India (10.1%) than in Taiwan (5.5%), Korea (3.0%), and China (2.5%). FTCs were more commonly diagnosed as category IV in Japan (77.5%) than in Korea (33.3%) and China (35.0%). Nuclear pleomorphism, nuclear crowding, microfollicular pattern, and dyshesive cell pattern were more common in FTCs compared with FAs. Conclusions: Our study highlighted the difference in FNAC diagnostic categories of FTCs among Asian countries, which is likely related to different reporting systems and thyroid cancer incidence. Cytologic features such as nuclear pleomorphism, nuclear crowding, microfollicular pattern, and dyshesive cell pattern were found to be useful in diagnosing FTCs more effectively.

Background/Aims: The proposed eosinophilic esophagitis (EoE) endoscopic reference score serves to diagnose and evaluate treatment responses in EoE.Nevertheless, the validated reference score thresholds for diagnosis and treatment response in Asian patients are yet to be established.This study aims to establish these thresholds for the first time among Asian patients with EoE. Methods: Patients presenting with ≥ 15 eosinophils/high power field and esophageal dysfunction symptoms between August 2007 andNovember 2021 were included. Age- and sex-matched non-EoE controls were also enrolled. Baseline characteristics, endoscopic reference score features, and scores were compared between patients and controls. Among patients, endoscopic reference score features and scores, along with peak eosinophil counts, were evaluated both before and after treatment. The optimal threshold was determined based on sensitivity, specificity, and the Youden index. Results: Overall, 102 patients were enrolled (74.5% men; mean age, 46.9 years). The mean endoscopic reference score was 2.65 and 0.52 for patients and controls, respectively (P < 0.001). An endoscopic reference score ≥ 2 was identified as the optimal diagnostic threshold for EoE (sensitivity, 0.79; specificity, 0.86; Youden index, 0.66). Post-treatment data regarding endoscopic findings and histology wereavailable for 30 patients. Regarding histologic response, an endoscopic reference score of ≤ 3 demonstrated the optimal threshold(sensitivity, 0.95; specificity, 0.88; Youden index, 0.83). Conclusions The optimal diagnostic and treatment response thresholds were determined to be endoscopic reference scores of ≥ 2 and ≤ 3,respectively. Further studies involving a larger patient cohort are necessary to validate these findings.

This study was designed to compare diagnostic categories of thyroid fine needle aspiration cytology (FNAC) and incidence of thyroid tumors in the multi-institutional Asian series with a special focus on diagnostic category IV (suspicious for a follicular neoplasm) and follicular thyroid carcinomas (FTCs). Methods: Distribution of FNAC categories, incidence of thyroid tumors in resection specimens and cytologic diagnoses of surgically confirmed follicular adenomas (FAs) and FTCs were collected from 10 institutes from five Asian countries and were compared among countries and between FAs and FTCs. Results: The frequency of category IV diagnoses (3.0%) in preoperative FNAC were significantly lower compared to those in Western countries (10.1%). When comparing diagnostic categories among Asian countries, category IV was more frequent in Japan (4.6%) and India (7.9%) than in Taiwan (1.4%), Korea (1.4%), and China (3.6%). Similarly, incidence of FAs and FTCs in surgical resection specimens was significantly higher in Japan (10.9%) and India (10.1%) than in Taiwan (5.5%), Korea (3.0%), and China (2.5%). FTCs were more commonly diagnosed as category IV in Japan (77.5%) than in Korea (33.3%) and China (35.0%). Nuclear pleomorphism, nuclear crowding, microfollicular pattern, and dyshesive cell pattern were more common in FTCs compared with FAs. Conclusions: Our study highlighted the difference in FNAC diagnostic categories of FTCs among Asian countries, which is likely related to different reporting systems and thyroid cancer incidence. Cytologic features such as nuclear pleomorphism, nuclear crowding, microfollicular pattern, and dyshesive cell pattern were found to be useful in diagnosing FTCs more effectively.