Circulating tumor DNA (ctDNA) has emerged as a promising tool for various clinical applications, including early diagnosis, therapeutic target identification, treatment response monitoring, prognosis evaluation, and minimal residual disease detection. Consequently, ctDNA assays have been incorporated into clinical practice. In this review, we offer an indepth exploration of the clinical implementation of ctDNA assays. Notably, we examined existing evidence related to pre-analytical procedures, analytical components in current technologies, and result interpretation and reporting processes. The primary objective of this guidelines is to provide recommendations for the clinical utilization of ctDNA assays.

Next-generation sequencing (NGS)-based liquid biopsy using peripheral blood offers a minimally invasive approach to detect tumor-derived circulating tumor DNA (ctDNA). Given the low abundance of ctDNA, accurate analysis is crucial, necessitating external quality assessments.Since 2020, the Korean Association of External Quality Assessment Service has conducted proficiency testing for NGS-based liquid biopsy. This study reviews the proficiency testing results from 2020 to 2023. The program was conducted biannually. Specimens were created by spiking fragmented DNA into fresh frozen plasma to simulate actual clinical samples. The number of target genes reported increased from 5 in 2020 to 17 in 2023. Results were assessed based on concordance with those obtained from targeted NGS panel testing performed before shipping the manufactured specimens.Participating laboratories used various NGS instruments and reagents. The read depth for each genetic variant varied across laboratories, while the reported read percentage of detected variants was generally consistent.Most laboratories accurately reported variants; however, some discrepancies related to variant position descriptions or incorrect reference sequence transcripts were noted. This study evaluates the performance of Korean clinical laboratories in NGS-based liquid biopsy. Continued vigilance in result reporting is necessary, and ongoing external quality assessments can enhance the reliability of NGS-based liquid biopsy testing.

Next-generation sequencing (NGS)-based liquid biopsy using peripheral blood offers a minimally invasive approach to detect tumor-derived circulating tumor DNA (ctDNA). Given the low abundance of ctDNA, accurate analysis is crucial, necessitating external quality assessments.Since 2020, the Korean Association of External Quality Assessment Service has conducted proficiency testing for NGS-based liquid biopsy. This study reviews the proficiency testing results from 2020 to 2023. The program was conducted biannually. Specimens were created by spiking fragmented DNA into fresh frozen plasma to simulate actual clinical samples. The number of target genes reported increased from 5 in 2020 to 17 in 2023. Results were assessed based on concordance with those obtained from targeted NGS panel testing performed before shipping the manufactured specimens.Participating laboratories used various NGS instruments and reagents. The read depth for each genetic variant varied across laboratories, while the reported read percentage of detected variants was generally consistent.Most laboratories accurately reported variants; however, some discrepancies related to variant position descriptions or incorrect reference sequence transcripts were noted. This study evaluates the performance of Korean clinical laboratories in NGS-based liquid biopsy. Continued vigilance in result reporting is necessary, and ongoing external quality assessments can enhance the reliability of NGS-based liquid biopsy testing.

Next-generation sequencing (NGS)-based liquid biopsy using peripheral blood offers a minimally invasive approach to detect tumor-derived circulating tumor DNA (ctDNA). Given the low abundance of ctDNA, accurate analysis is crucial, necessitating external quality assessments.Since 2020, the Korean Association of External Quality Assessment Service has conducted proficiency testing for NGS-based liquid biopsy. This study reviews the proficiency testing results from 2020 to 2023. The program was conducted biannually. Specimens were created by spiking fragmented DNA into fresh frozen plasma to simulate actual clinical samples. The number of target genes reported increased from 5 in 2020 to 17 in 2023. Results were assessed based on concordance with those obtained from targeted NGS panel testing performed before shipping the manufactured specimens.Participating laboratories used various NGS instruments and reagents. The read depth for each genetic variant varied across laboratories, while the reported read percentage of detected variants was generally consistent.Most laboratories accurately reported variants; however, some discrepancies related to variant position descriptions or incorrect reference sequence transcripts were noted. This study evaluates the performance of Korean clinical laboratories in NGS-based liquid biopsy. Continued vigilance in result reporting is necessary, and ongoing external quality assessments can enhance the reliability of NGS-based liquid biopsy testing.

We retrospectively examined current trends in ordering for erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) testing. All claims corresponding to ESR and CRP testing for hospital visits in 2022 were obtained from a platform operated by the Health Insurance and Review Agency. The annual (2018–2022) utilization and cost of ESR and CRP, total inpatient days, and patient encounters with outpatients were retrieved. The number of ESR and CRP tests gradually increased over 5 years, except a slight decrease in 2020. The proportion of claims with co-ordering of ESR and CRP tests was 46.64%. More than 60% co-ordering claims were observed in orthopedic surgery, neurosurgery, and plastic surgery departments. The proportion of co-orders was relatively high in inpatient setting and primary hospitals. This study indicated frequent co-ordering patterns of ESR and CRP tests, highlighting an urgent need for diagnostic stewardship programs on ESR and CRP testing in Korea.

We retrospectively examined current trends in ordering for erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) testing. All claims corresponding to ESR and CRP testing for hospital visits in 2022 were obtained from a platform operated by the Health Insurance and Review Agency. The annual (2018–2022) utilization and cost of ESR and CRP, total inpatient days, and patient encounters with outpatients were retrieved. The number of ESR and CRP tests gradually increased over 5 years, except a slight decrease in 2020. The proportion of claims with co-ordering of ESR and CRP tests was 46.64%. More than 60% co-ordering claims were observed in orthopedic surgery, neurosurgery, and plastic surgery departments. The proportion of co-orders was relatively high in inpatient setting and primary hospitals. This study indicated frequent co-ordering patterns of ESR and CRP tests, highlighting an urgent need for diagnostic stewardship programs on ESR and CRP testing in Korea.

Purpose: Although numerous studies have identified potential risk factors for ipsilateral lymphedema development in patients with breast cancer following axillary node dissection, the risk factors for lymphedema in patients undergoing sentinel node biopsy without axillary dissection remain unclear. In this study, we aimed to determine the real-world incidence and risk factors for lymphedema in such patients. Methods: We conducted a single-center, retrospective review of medical records of patients with breast cancer who underwent sentinel node biopsy alone. The development cohort (5,051 patients, January 2017–December 2020) was analyzed to identify predictors of lymphedema, and a predictive model was subsequently created. A validation cohort (1,627 patients, January 2014–December 2016) was used to validate the model. Results: In the development cohort, 49 patients (0.9%) developed lymphedema over a median follow-up of 56 months, with most cases occurring within the first three years post-operation.Multivariate analysis revealed that a body mass index (BMI) of 30 kg/m2 or above, radiation therapy (RTx), chemotherapy, and more than three harvested lymph nodes significantly predicted lymphedema. The predictive model showed an area under the curve of 0.824 for systemic chemotherapy, with the number of harvested lymph nodes being the most significant factor. Patients were stratified into four risk groups, showing lymphedema incidences of 3.3% in the highest-risk group and 0.1% in the lowest-risk group. In the validation cohort, the incidences were 1.7% and 0.2% for the highest and lowest risk groups, respectively. Conclusion The lymphedema prediction model identifies RTx, chemotherapy, BMI ≥ 30 kg/m2 , and more than three harvested lymph nodes as significant risk factors. Although the overall incidence is low, the risk is notably influenced by the extent of lymph node removal and systemic therapies. The model’s high negative predictive value supports its application in designing tailored lymphedema surveillance programs for early intervention.