1.Novel Bronchoscopy Method for Molecular Profiling of Lung Cancer: Targeted Washing Technique
Mi-Hyun KIM ; Hayoung SEONG ; Hyojin JANG ; Saerom KIM ; Wanho YOO ; Soo Han KIM ; Jeongha MOK ; Kwangha LEE ; Ki Uk KIM ; Min Ki LEE ; Jung Seop EOM
Cancer Research and Treatment 2026;58(1):107-114
Purpose:
There have been efforts to find alternative samples other than standard samples of tissue or plasma for mutational analyses for lung cancer patients. However, no other sample or technique has replaced the mutational analyses using standard samples. In this prospective study, we assessed a novel bronchoscopy method, named as targeted washing technique, for detecting the epidermal growth factor receptor (EGFR) mutation.
Materials and Methods:
A 3.0-mm ultrathin bronchoscope was precisely navigated to the target lung lesion with the assistance of virtual bronchoscopic navigation and fluoroscopy. Once the bronchoscope is placed in front of target lung lesion, 0.9% normal saline was instilled for targeted washing. EGFR testing using targeted washing fluid (TWF) was compared to standard methods using plasma or tumor tissue.
Results:
In 41 TWF samples, the T790M mutation was detected in tissue, plasma, and TWF samples at rates of 22.0%, 9.8%, and 29.3%, respectively. The overall EGFR T790M detection rate using tissue, plasma, or TWF samples was 36.6%, with TWF samples increasing the T790M mutation detection rate by up to 10%. The accuracy of T790M mutation detection using TWF sample was 82.9% compared with standard samples. Four patients were found to have the EGFR T790M mutation solely through EGFR testing using TWF, which repeated rebiopsies using either plasma or tissue finally confirmed to have the T790M mutation.
Conclusion
We demonstrated the clinical potential of targeted washing technique for molecular testing, which can be a good option to overcome spatial heterogeneity, low sensitivity of plasma sample or technical limitations in collecting tumor tissues.
2.High-Dose Rifampicin for 3 Months after Culture Conversion for Drug-Susceptible Pulmonary Tuberculosis
Nakwon KWAK ; Joong-Yub KIM ; Hyung-Jun KIM ; Byoung-Soo KWON ; Jae Ho LEE ; Jeongha MOK ; Yong-Soo KWON ; Young Ae KANG ; Youngmok PARK ; Ji Yeon LEE ; Doosoo JEON ; Jung-Kyu LEE ; Jeong Seong YANG ; Jake WHANG ; Kyung Jong KIM ; Young Ran KIM ; Minkyoung CHEON ; Jiwon PARK ; Seokyung HAHN ; Jae-Joon YIM
Tuberculosis and Respiratory Diseases 2025;88(1):170-180
Background:
This study aimed to determine whether a shorter high-dose rifampicin regimen is non-inferior to the standard 6-month tuberculosis regimen.
Methods:
This multicenter, randomized, open-label, non-inferiority trial enrolled participants with respiratory specimen positivity by Xpert MTB/RIF assay or Mycobacterium tuberculosis culture without rifampicin-resistance. Participants were randomized at 1:1 to the investigational or control group. The investigational group received high-dose rifampicin (30 mg/kg/day), isoniazid, and pyrazinamide until culture conversion, followed by high-dose rifampicin and isoniazid for 12 weeks. The control group received the standard 6-month regimen. The primary outcome was the rate of unfavorable outcomes at 18 months post-randomization. The non-inferiority margin was set at <6% difference in unfavorable outcomes rates. The study is registered with ClinicalTrials.gov (NCT04485156)
Results:
Between 4 November 2020 and 3 January 2022, 76 participants were enrolled. Of these, 58 were included in the modified intention-to-treat analysis. Unfavorable outcomes occurred in 10 (31.3%) of 32 in the control group and 10 (38.5%) of 26 in the investigational group. The difference was 7.2% (95% confidence interval, ∞ to 31.9%), failing to prove non-inferiority. Serious adverse events and grade 3 or higher adverse events did not differ between the groups.
Conclusion
The shorter high-dose rifampicin regimen failed to demonstrate non-inferiority but had an acceptable safety profile.
3.Comparison of Patients Who Were Not Evaluated and Lost to Follow-Up with Multidrug/Rifampin-Resistant Tuberculosis in South Korea
Hongjo CHOI ; Jeongha MOK ; Young Ae KANG ; Dawoon JEONG ; Hee-Yeon KANG ; Hee Jin KIM ; Hee-Sun KIM ; Doosoo JEON
Yonsei Medical Journal 2025;66(1):16-24
Purpose:
This study aimed to evaluate the prognosis of the not evaluated (NE) group by comparing it with the lost to follow-up (LTFU) group among patients with multidrug/rifampin-resistant tuberculosis (MDR/RR-TB).
Materials and Methods:
This was a retrospective longitudinal follow-up study using an integrated database constructed by data linkage of the three national databases. This database included 7226 cases of MDR/RR-TB notified between 2011 and 2017 in South Korea.
Results:
Among the 7226 MDR/RR-TB cases, 730 (10.1%) were classified as LTFU group, and 353 (4.9%) as NE group. When comparing NE group with LTFU group, there were no significant differences in the all-cause mortality rate (18.1% vs. 13.8%, p=0.065), median time to death [404 days (interquartile range, IQR 46–850) vs. 443 days (IQR 185–1157), p=0.140], and retreatment rate (26.9% vs.22.2%, p=0.090). After adjusting for potential confounders, the adjusted hazard ratio (aHR) for all-cause mortality (aHR 1.11; 95% confidence interval 0.80-1.53; p=0.531) in NE group was not significantly different than that in LTFU group. Among retreated cases, NE group had a higher treatment success rate (57.9% vs 43.8%, p=0.029) and a lower LTFU rate (11.6% vs 38.3%, p<0.001) compared to LTFU group.
Conclusion
NE group had an unfavorable outcome comparable to LTFU group, suggesting undetected cases of LTFU or deaths during the referral process. Establishing an efficient patient referral system would contribute to reducing the incidence of NE cases.
4.High-Dose Rifampicin for 3 Months after Culture Conversion for Drug-Susceptible Pulmonary Tuberculosis
Nakwon KWAK ; Joong-Yub KIM ; Hyung-Jun KIM ; Byoung-Soo KWON ; Jae Ho LEE ; Jeongha MOK ; Yong-Soo KWON ; Young Ae KANG ; Youngmok PARK ; Ji Yeon LEE ; Doosoo JEON ; Jung-Kyu LEE ; Jeong Seong YANG ; Jake WHANG ; Kyung Jong KIM ; Young Ran KIM ; Minkyoung CHEON ; Jiwon PARK ; Seokyung HAHN ; Jae-Joon YIM
Tuberculosis and Respiratory Diseases 2025;88(1):170-180
Background:
This study aimed to determine whether a shorter high-dose rifampicin regimen is non-inferior to the standard 6-month tuberculosis regimen.
Methods:
This multicenter, randomized, open-label, non-inferiority trial enrolled participants with respiratory specimen positivity by Xpert MTB/RIF assay or Mycobacterium tuberculosis culture without rifampicin-resistance. Participants were randomized at 1:1 to the investigational or control group. The investigational group received high-dose rifampicin (30 mg/kg/day), isoniazid, and pyrazinamide until culture conversion, followed by high-dose rifampicin and isoniazid for 12 weeks. The control group received the standard 6-month regimen. The primary outcome was the rate of unfavorable outcomes at 18 months post-randomization. The non-inferiority margin was set at <6% difference in unfavorable outcomes rates. The study is registered with ClinicalTrials.gov (NCT04485156)
Results:
Between 4 November 2020 and 3 January 2022, 76 participants were enrolled. Of these, 58 were included in the modified intention-to-treat analysis. Unfavorable outcomes occurred in 10 (31.3%) of 32 in the control group and 10 (38.5%) of 26 in the investigational group. The difference was 7.2% (95% confidence interval, ∞ to 31.9%), failing to prove non-inferiority. Serious adverse events and grade 3 or higher adverse events did not differ between the groups.
Conclusion
The shorter high-dose rifampicin regimen failed to demonstrate non-inferiority but had an acceptable safety profile.
5.Comparison of Patients Who Were Not Evaluated and Lost to Follow-Up with Multidrug/Rifampin-Resistant Tuberculosis in South Korea
Hongjo CHOI ; Jeongha MOK ; Young Ae KANG ; Dawoon JEONG ; Hee-Yeon KANG ; Hee Jin KIM ; Hee-Sun KIM ; Doosoo JEON
Yonsei Medical Journal 2025;66(1):16-24
Purpose:
This study aimed to evaluate the prognosis of the not evaluated (NE) group by comparing it with the lost to follow-up (LTFU) group among patients with multidrug/rifampin-resistant tuberculosis (MDR/RR-TB).
Materials and Methods:
This was a retrospective longitudinal follow-up study using an integrated database constructed by data linkage of the three national databases. This database included 7226 cases of MDR/RR-TB notified between 2011 and 2017 in South Korea.
Results:
Among the 7226 MDR/RR-TB cases, 730 (10.1%) were classified as LTFU group, and 353 (4.9%) as NE group. When comparing NE group with LTFU group, there were no significant differences in the all-cause mortality rate (18.1% vs. 13.8%, p=0.065), median time to death [404 days (interquartile range, IQR 46–850) vs. 443 days (IQR 185–1157), p=0.140], and retreatment rate (26.9% vs.22.2%, p=0.090). After adjusting for potential confounders, the adjusted hazard ratio (aHR) for all-cause mortality (aHR 1.11; 95% confidence interval 0.80-1.53; p=0.531) in NE group was not significantly different than that in LTFU group. Among retreated cases, NE group had a higher treatment success rate (57.9% vs 43.8%, p=0.029) and a lower LTFU rate (11.6% vs 38.3%, p<0.001) compared to LTFU group.
Conclusion
NE group had an unfavorable outcome comparable to LTFU group, suggesting undetected cases of LTFU or deaths during the referral process. Establishing an efficient patient referral system would contribute to reducing the incidence of NE cases.
6.High-Dose Rifampicin for 3 Months after Culture Conversion for Drug-Susceptible Pulmonary Tuberculosis
Nakwon KWAK ; Joong-Yub KIM ; Hyung-Jun KIM ; Byoung-Soo KWON ; Jae Ho LEE ; Jeongha MOK ; Yong-Soo KWON ; Young Ae KANG ; Youngmok PARK ; Ji Yeon LEE ; Doosoo JEON ; Jung-Kyu LEE ; Jeong Seong YANG ; Jake WHANG ; Kyung Jong KIM ; Young Ran KIM ; Minkyoung CHEON ; Jiwon PARK ; Seokyung HAHN ; Jae-Joon YIM
Tuberculosis and Respiratory Diseases 2025;88(1):170-180
Background:
This study aimed to determine whether a shorter high-dose rifampicin regimen is non-inferior to the standard 6-month tuberculosis regimen.
Methods:
This multicenter, randomized, open-label, non-inferiority trial enrolled participants with respiratory specimen positivity by Xpert MTB/RIF assay or Mycobacterium tuberculosis culture without rifampicin-resistance. Participants were randomized at 1:1 to the investigational or control group. The investigational group received high-dose rifampicin (30 mg/kg/day), isoniazid, and pyrazinamide until culture conversion, followed by high-dose rifampicin and isoniazid for 12 weeks. The control group received the standard 6-month regimen. The primary outcome was the rate of unfavorable outcomes at 18 months post-randomization. The non-inferiority margin was set at <6% difference in unfavorable outcomes rates. The study is registered with ClinicalTrials.gov (NCT04485156)
Results:
Between 4 November 2020 and 3 January 2022, 76 participants were enrolled. Of these, 58 were included in the modified intention-to-treat analysis. Unfavorable outcomes occurred in 10 (31.3%) of 32 in the control group and 10 (38.5%) of 26 in the investigational group. The difference was 7.2% (95% confidence interval, ∞ to 31.9%), failing to prove non-inferiority. Serious adverse events and grade 3 or higher adverse events did not differ between the groups.
Conclusion
The shorter high-dose rifampicin regimen failed to demonstrate non-inferiority but had an acceptable safety profile.
7.Comparison of Patients Who Were Not Evaluated and Lost to Follow-Up with Multidrug/Rifampin-Resistant Tuberculosis in South Korea
Hongjo CHOI ; Jeongha MOK ; Young Ae KANG ; Dawoon JEONG ; Hee-Yeon KANG ; Hee Jin KIM ; Hee-Sun KIM ; Doosoo JEON
Yonsei Medical Journal 2025;66(1):16-24
Purpose:
This study aimed to evaluate the prognosis of the not evaluated (NE) group by comparing it with the lost to follow-up (LTFU) group among patients with multidrug/rifampin-resistant tuberculosis (MDR/RR-TB).
Materials and Methods:
This was a retrospective longitudinal follow-up study using an integrated database constructed by data linkage of the three national databases. This database included 7226 cases of MDR/RR-TB notified between 2011 and 2017 in South Korea.
Results:
Among the 7226 MDR/RR-TB cases, 730 (10.1%) were classified as LTFU group, and 353 (4.9%) as NE group. When comparing NE group with LTFU group, there were no significant differences in the all-cause mortality rate (18.1% vs. 13.8%, p=0.065), median time to death [404 days (interquartile range, IQR 46–850) vs. 443 days (IQR 185–1157), p=0.140], and retreatment rate (26.9% vs.22.2%, p=0.090). After adjusting for potential confounders, the adjusted hazard ratio (aHR) for all-cause mortality (aHR 1.11; 95% confidence interval 0.80-1.53; p=0.531) in NE group was not significantly different than that in LTFU group. Among retreated cases, NE group had a higher treatment success rate (57.9% vs 43.8%, p=0.029) and a lower LTFU rate (11.6% vs 38.3%, p<0.001) compared to LTFU group.
Conclusion
NE group had an unfavorable outcome comparable to LTFU group, suggesting undetected cases of LTFU or deaths during the referral process. Establishing an efficient patient referral system would contribute to reducing the incidence of NE cases.
8.High-Dose Rifampicin for 3 Months after Culture Conversion for Drug-Susceptible Pulmonary Tuberculosis
Nakwon KWAK ; Joong-Yub KIM ; Hyung-Jun KIM ; Byoung-Soo KWON ; Jae Ho LEE ; Jeongha MOK ; Yong-Soo KWON ; Young Ae KANG ; Youngmok PARK ; Ji Yeon LEE ; Doosoo JEON ; Jung-Kyu LEE ; Jeong Seong YANG ; Jake WHANG ; Kyung Jong KIM ; Young Ran KIM ; Minkyoung CHEON ; Jiwon PARK ; Seokyung HAHN ; Jae-Joon YIM
Tuberculosis and Respiratory Diseases 2025;88(1):170-180
Background:
This study aimed to determine whether a shorter high-dose rifampicin regimen is non-inferior to the standard 6-month tuberculosis regimen.
Methods:
This multicenter, randomized, open-label, non-inferiority trial enrolled participants with respiratory specimen positivity by Xpert MTB/RIF assay or Mycobacterium tuberculosis culture without rifampicin-resistance. Participants were randomized at 1:1 to the investigational or control group. The investigational group received high-dose rifampicin (30 mg/kg/day), isoniazid, and pyrazinamide until culture conversion, followed by high-dose rifampicin and isoniazid for 12 weeks. The control group received the standard 6-month regimen. The primary outcome was the rate of unfavorable outcomes at 18 months post-randomization. The non-inferiority margin was set at <6% difference in unfavorable outcomes rates. The study is registered with ClinicalTrials.gov (NCT04485156)
Results:
Between 4 November 2020 and 3 January 2022, 76 participants were enrolled. Of these, 58 were included in the modified intention-to-treat analysis. Unfavorable outcomes occurred in 10 (31.3%) of 32 in the control group and 10 (38.5%) of 26 in the investigational group. The difference was 7.2% (95% confidence interval, ∞ to 31.9%), failing to prove non-inferiority. Serious adverse events and grade 3 or higher adverse events did not differ between the groups.
Conclusion
The shorter high-dose rifampicin regimen failed to demonstrate non-inferiority but had an acceptable safety profile.
9.Comparison of Patients Who Were Not Evaluated and Lost to Follow-Up with Multidrug/Rifampin-Resistant Tuberculosis in South Korea
Hongjo CHOI ; Jeongha MOK ; Young Ae KANG ; Dawoon JEONG ; Hee-Yeon KANG ; Hee Jin KIM ; Hee-Sun KIM ; Doosoo JEON
Yonsei Medical Journal 2025;66(1):16-24
Purpose:
This study aimed to evaluate the prognosis of the not evaluated (NE) group by comparing it with the lost to follow-up (LTFU) group among patients with multidrug/rifampin-resistant tuberculosis (MDR/RR-TB).
Materials and Methods:
This was a retrospective longitudinal follow-up study using an integrated database constructed by data linkage of the three national databases. This database included 7226 cases of MDR/RR-TB notified between 2011 and 2017 in South Korea.
Results:
Among the 7226 MDR/RR-TB cases, 730 (10.1%) were classified as LTFU group, and 353 (4.9%) as NE group. When comparing NE group with LTFU group, there were no significant differences in the all-cause mortality rate (18.1% vs. 13.8%, p=0.065), median time to death [404 days (interquartile range, IQR 46–850) vs. 443 days (IQR 185–1157), p=0.140], and retreatment rate (26.9% vs.22.2%, p=0.090). After adjusting for potential confounders, the adjusted hazard ratio (aHR) for all-cause mortality (aHR 1.11; 95% confidence interval 0.80-1.53; p=0.531) in NE group was not significantly different than that in LTFU group. Among retreated cases, NE group had a higher treatment success rate (57.9% vs 43.8%, p=0.029) and a lower LTFU rate (11.6% vs 38.3%, p<0.001) compared to LTFU group.
Conclusion
NE group had an unfavorable outcome comparable to LTFU group, suggesting undetected cases of LTFU or deaths during the referral process. Establishing an efficient patient referral system would contribute to reducing the incidence of NE cases.
10.High-Dose Rifampicin for 3 Months after Culture Conversion for Drug-Susceptible Pulmonary Tuberculosis
Nakwon KWAK ; Joong-Yub KIM ; Hyung-Jun KIM ; Byoung-Soo KWON ; Jae Ho LEE ; Jeongha MOK ; Yong-Soo KWON ; Young Ae KANG ; Youngmok PARK ; Ji Yeon LEE ; Doosoo JEON ; Jung-Kyu LEE ; Jeong Seong YANG ; Jake WHANG ; Kyung Jong KIM ; Young Ran KIM ; Minkyoung CHEON ; Jiwon PARK ; Seokyung HAHN ; Jae-Joon YIM
Tuberculosis and Respiratory Diseases 2025;88(1):170-180
Background:
This study aimed to determine whether a shorter high-dose rifampicin regimen is non-inferior to the standard 6-month tuberculosis regimen.
Methods:
This multicenter, randomized, open-label, non-inferiority trial enrolled participants with respiratory specimen positivity by Xpert MTB/RIF assay or Mycobacterium tuberculosis culture without rifampicin-resistance. Participants were randomized at 1:1 to the investigational or control group. The investigational group received high-dose rifampicin (30 mg/kg/day), isoniazid, and pyrazinamide until culture conversion, followed by high-dose rifampicin and isoniazid for 12 weeks. The control group received the standard 6-month regimen. The primary outcome was the rate of unfavorable outcomes at 18 months post-randomization. The non-inferiority margin was set at <6% difference in unfavorable outcomes rates. The study is registered with ClinicalTrials.gov (NCT04485156)
Results:
Between 4 November 2020 and 3 January 2022, 76 participants were enrolled. Of these, 58 were included in the modified intention-to-treat analysis. Unfavorable outcomes occurred in 10 (31.3%) of 32 in the control group and 10 (38.5%) of 26 in the investigational group. The difference was 7.2% (95% confidence interval, ∞ to 31.9%), failing to prove non-inferiority. Serious adverse events and grade 3 or higher adverse events did not differ between the groups.
Conclusion
The shorter high-dose rifampicin regimen failed to demonstrate non-inferiority but had an acceptable safety profile.

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